2 Roof Temperature 

Histories in Matched 

Attics in Mississippi 

and Wisconsin 

Jerrold E. Winandy 

H. Michael Barnes 

Cherilyn A. Hatfield 

United States

Department of 

Agriculture 

Forest Service 

Forest 

Products 

Laboratory 

Research 

Paper 

FPL−RP−589 
Abstract 

To address the problem of defining actual field temperatures 

of various wood components in wood-framed roof systems, 

roof temperatures were monitored in test structures situated 

in the northern and southern United States (Madison, Wisconsin, and Starkville, Mississippi, respectively). The field 

exposure structures were intended to simulate the attics of 

multifamily wood-framed structures for which Model Building Codes sometimes allow the use of fire-retardant-treated 

roof sheathing. The structures were instrumented to monitor 

interior attic air, exterior air, inner and outer plywood roof 

sheathing, and internal rafter temperatures in dry whiteshingled structures and both dry and heavily humidified 

black-shingled structures. Temperatures were recorded from 

January 1992 through December 1999 in Wisconsin and 

from January 1996 through December 1999 in Mississippi. 

The Mississippi exposure generally induced 5°C to 10°C 

higher temperatures than did the Madison exposure, though 

the difference in annual maximum “1-h average” temperature 

of both exposures was usually no more than 3°C to 4°C. 

December 2000 

Winandy, Jerrold E.; Barnes, H. Michael; Hatfield, Cherilyn A. 2000. Roof 

temperature histories in matched attics in Mississippi and Wisconsin. Res. 

Pap. FPL–RP–589. Madison, WI: U.S. Department of Agriculture, Forest 

Service, Forest Products Laboratory. 24 p. 

A limited number of free copies of this publication are available to the 

public from the Forest Products Laboratory, One Gifford Pinchot Drive, 

Madison, WI 53705–2398. Laboratory publications are sent to hundreds 

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Overall, black-shingled roof systems tended to be 5°C to 

10°C warmer during the midafternoon of a sunny day than 

were comparable white-shingled roof systems. Few differences in plywood roof sheathing temperatures were noted 

between dry and heavily humidified structures. Attic airspace and rafter temperatures were generally 5°C to 10°C 

cooler in humidified attics than in dry attics. 

The major difference in the temperature of wood components 

in the Wisconsin and Mississippi structures occurred during 

the winter, when temperatures were as much as 20°C lower 

in Wisconsin. 

Keywords: roof temperature, plywood, roof sheathing, rafter, 

thermal degrade, fire-retardant treatment, shingles, attic 

Contents 

 Page

Problem............................................................................... 1

Objectives ........................................................................... 1

Background......................................................................... 1

Methods .............................................................................. 2

Exposure Structures ........................................................ 2

Recording of Temperatures............................................. 3

Measurement of Moisture Content.................................. 5

Results and Discussion........................................................ 5

Sheathing Temperatures.................................................. 5

Exceedance Temperatures .............................................. 5

Maximum Temperatures ................................................. 5

Annual Temperature Trends ........................................... 6

Peak Temperature Trends ............................................... 9

Moisture Content .......................................................... 11

Concluding Remarks......................................................... 11

Acknowledgments............................................................. 16

References......................................................................... 16

Appendix A—Exceedance Temperature Data for WI 

Structures .......................................................................... 17

Appendix B—Exceedance Temperature Data for MS 

Structures .......................................................................... 22
Roof Temperature Histories in Matched 

Attics in Misissippi and Wisconsin 

Jerrold E. Winandy, Research Wood Scientist

Forest Products Laboratory, Madison, Wisconsin 

H. Michael Barnes, Professor

Mississippi State University, Mississippi 

Cherilyn, A. Hatfield, Statistician 

Forest Products Laboratory, Madison, Wisconsin 

Problem 

In the late 1980s, the degradation of wood treated with some 

fire retardant (FR) chemicals in roof systems became a problem of major national significance. Thousands of cases were 

reported throughout the eastern United States (NAHB 1990). 

Our understanding of this deterioration in serviceability 

caused by thermal degrade has been limited because we have 

been unable to specifically correlate laboratory experiments 

using steady-state and cyclic temperature exposures with 

actual diurnal field temperature histories of FR-treated roof 

sheathing plywood. This lack of correlation has inhibited our 

ability to predict thermal-induced degradation of FR-treated 

plywood in the field from thermal degradation rates derived 

in the laboratory. 

In many reports of field problems with FR-treated plywood 

roof sheathing, improper or nonfunctional ventilation of roof 

systems was attributed as a co-contributor to thermal degradation (LeVan and Collet 1989, NAHB 1990). This has 

resulted in questions about the relationship between roof 

system temperatures in damp, nonventilated attics compared 

with normally dry systems and the potential for synergy 

between roof temperatures and roof moisture. 

Objectives 

The primary objective of this work is to collect actual field 

data documenting the actual thermal load history of various 

wood components in traditional light-framed structures. The 

roof temperature histories presented in this report provide 

reasonable estimates of actual thermal loads. In addition, the 

histories provide insight into the effects of shingle color, attic 

humidity, and climate on thermal loads and a data base for 

modeling the residual serviceability of roof sheathing for 

known wood thermal degradation rates (Lebow and Winandy 

1999). The secondary objective of this work is to use 

matched laboratory and field data on mechanical properties 

to develop specific laboratory-to-field correlations. These 

correlations will provide specific guidance for deriving the 

cyclic factor used in Section 7 of ASTM D6305 (ASTM 

1999) because the current cyclic factor is an arbitrarily 

derived estimate rather than a calculated estimate. This report 

specifically addresses the primary objective and presents the 

findings from one of more than a dozen interrelated studies 

conducted in a 10-year research program to develop residual 

serviceability models for roof sheathing (Winandy 2000). 

Background 

Heyer (1963) reported temperature histories for wall and roof 

systems for six houses and one office building for 1 week to 

2 consecutive summers (June–August). The houses were 

located in Tucson, Arizona; Athens, Georgia; Portland, 

Oregon; Diboll, Texas; and Madison, Wisconsin. The office 

building, which had served as the original headquarters of the 

Forest Products Society, was located in Madison, Wisconsin. 

In any one year, maximum roof temperatures were found to 

reach as high as 75°C but the cumulative duration of temperatures over 70°C did not exceed 21 h, and the cumulative 

duration of temperatures over 65°C did not exceed 64 h. This 

was thought to be important considering that design standards for wood (AF&PA 1997) require a strength property 

adjustment for sustained exposures above 37.8°C and greater 

adjustment for prolonged exposures up to 65.6°C. 

Roof temperatures attained by structures have been modeled. 

Ozkan (1993) and Wilkes (1989) reported on surface and 

various component temperatures in flat roof systems. Wood 

sheathing temperatures were not considered. In the study by 

Ozkan (1993), which was conducted in a very hot and dry 

area in Arabia, temperatures of roofing surfaces of a field 

station reached 93°C during a 11⁄2-year period (April 1989 to 

November 1990). The primary use of the station was to 

observe the effects of weathering and to measure the temperatures of the bituminous and polymeric waterproofing 

membranes and thermal insulation materials. In the study by 

Wilkes (1989), temperatures of metal roofs in eastern Tennessee reached as high as 73°C during January and May. For 

more exposure temperature histories for shingles, the reader 
2 

is referred to studies by the National Bureau of Standards 

(NBS 1979) and Blackenstowe (1987). The temperature 

histories discussed hereafter pertain to wood components of 

roof systems. 

Computer models have been developed that predict the average temperature and moisture content of plywood roof 

sheathing and other lumber roof members based on various 

construction details, materials, ventilation factors, and solar 

gain (radiation load) for the roof (APA 1989, ASTM 1988, 

TenWolde 1997, Wilkes 1989). The APA–Engineered Wood 

Association reported on a model that predicts temperatures 

of plywood roof sheathing under a black membrane in flatroofed systems. This model predicts that sheathing temperatures of 65°C, 70°C, 75°C, and 80°C might be exceeded for 

up to 36, 13, 5, and 2 h, respectively, over the course of an 

average year in Hartford, Connecticut (APA 1989). Wilkes 

(1989) developed and reported a predictive roof temperature 

model for multi-layer nonwood roof systems. This model 

does not account for moisture flux, which may be critical in 

wood roof systems. 

TenWolde developed and later verified (TenWolde 1988 and 

1997, respectively) a predictive roof temperature model. In 

the 1997 report, he described a predictive roof temperature 

model especially for sloped wood-based roof systems. This 

model shows that the surface temperature of plywood roof 

sheathing is dominated by solar gain and the heat exchange 

between the surface and ambient air, not by attic ventilation. 

Diurnal (daily cyclic) temperature variation and hourly 

sheathing temperature histories are also influenced by the 

radiant energy absorptivity of the roofing surface, roof pitch, 

and, to a lesser extent, insulation and attic ventilation. The 

TenWolde model predicts that wet plywood sheathing dries 

quickly under warm summer conditions, even if ventilation is 

minimal. For example, if plywood is installed at 60% moisture content, the moisture content is roughly 15% after 

1 week and falls to 8% in roughly 2 weeks. The model also 

indicates that the absorbtivity of solar (radiant) energy by the 

roofing material has the greatest effect on increasing or 

reducing the average temperature of the plywood roof sheathing. If the absorptivity of the roofing material is 0.92, the 

model predicts the maximum hourly temperature for the roof 

sheathing plywood as 60°C and the maximum predicted 

exterior roof membrane temperature as 66°C. If the absorptivity is changed to 0.2, supposedly representing a metal roof 

system, both the maximum predicted sheathing temperature 

and maximum predicted membrane temperature drop to 

35°C. Roof pitch has only a moderate influence on reducing 

the exterior surface temperature and the average temperature 

of the plywood. The model also predicts that the presence of 

insulation installed directly on the underside of the sheathing 

has virtually no influence on sheathing temperature on the 

top surface, but raises the average sheathing temperature 

relative to that of the top surface. When the ventilation rate in 

uninsulated systems is increased from 8 to about 21 air 

changes per hour, almost no decrease of the top surface 

sheathing temperature or the average sheathing temperature 

is predicted. 

In 1992, a test facility was constructed at the Building Research Council of the University of Illinois to measure heat 

transfer, moisture movement, and airflow in typical residential attic structures under natural conditions (Rose 1992). The 

results of that study showed that during the summer in central 

Illinois, attic ventilation could lower attic air temperature by 

15.5°C but sheathing temperature by only 5°C; information 

on rafter temperatures was not given. Attic ventilation had 

only a minor effect on roof shingle temperature. The findings 

of Rose (1995) affirmed the earlier predictions of TenWolde 

(1988) and were then used to verify the TenWolde model 

(1997). Eventually, the TenWolde model was used to predict 

roof temperature histories for plywood roof sheathing at a 

dozen locations across the Unites States. Those predictions 

were used to predict engineering design adjustments for FRtreated plywood roof sheathing in ASTM Standard D6305–

98 (ASTM 1999). 

Methods 

Exposure Structures 

In the summer of 1991, five field exposure structures were 

constructed near Madison, Wisconsin (43° latitude). In 

Madison, the average incidence angle of sunlight is 19.5° 

from the southern horizon on the winter solstice (December 

21) and 43° on the summer solstice (June 21). The annual 

average declination angle is 31.25°. The Wisconsin exposure 

structures (WI structures) were constructed to face south in a 

shadeless area open to direct sunlight. The structures were 

spaced far enough apart to prevent any one structure from 

shading the next structure. The construction of the WI structures was fully described by Winandy and Beaumont (1995). 

In 1994, a USDA Competitive Grant was received to construct and monitor matched exposure structures at the Mississippi Forest Products Laboratory, Mississippi State University, in Starkville, Mississippi (33.5° latitude). This research 

was part of an ongoing effort to relate temperatures in 

matched northern to southern U.S. roof systems (Barnes and 

others 1993). In Starkville, the average incidence angle of 

sunlight is 32.3° from the southern horizon on the winter 

solstice and 74.8° on the summer solstice. The annual average declination angle is 53.5°. The five exposure structures 

in Mississippi (MS structures) were constructed to face south 

in a shadeless area open to direct sunlight. As for the WI 

structures, the MS structures were spaced far enough apart to 

prevent any one structure from shading the next structure. 

The data from the MS structures provide a direct measure of 

a more severe (higher solar loading) location compared with 

Madison, Wisconsin (Winandy and Beaumont 1995). A 

typical exposure structure is shown in Figure 1. 
3 

Because of the slope of the Starkville test site, the east side 

of the MS structures was situated from 0.46 to 1.2 m off the 

ground, whereas the west side ranged from 0.15 to 0.46 m off 

the ground (Fig. 1). The WI structures were located on fairly 

flat ground and were approximately 0.5 m above grade. 

All 10 exposure structures were identical. They were 3.7 m 

wide by 4.9 m long and constructed to simulate part of a 

typical multifamily attic–roof system in which U.S. Model 

Building Codes sometimes allow FR-treated plywood roof 

sheathing. To replicate this type of construction on a smaller 

scale, the 3.7-m-wide structures simulated in cross section 

the 1/8- to 3/8-span section of a 14.8-m span, 3:12 pitch roof 

system in both roof area and attic volume (Winandy and 

Beaumont 1995). 

Each exposure structure was completely enclosed and unventilated. The four exterior walls were sheathed with 12-mmthick, 200-mm-grooved Southern Pine siding attached to 

nominal 2- by 4-in. (standard 38- by 89-mm) wall studs. The 

exterior surfaces were coated with one coat of primer and 

two top coats of latex solid-color (light gray, almost white) 

stain or paint. The walls, floors, and roof system were not 

insulated. 

The floor system was constructed from 9.5-mm-thick plywood floor sheathing and nominal 2- by 10-in. (standard 38- 

by 235-mm) joists. The rafters were made from nominal 

2- by 6-in. (standard 38- by 140-mm) lumber, and the roof 

sheathing was 19-mm-thick plywood. Thick plywood roof 

sheathing was required because sixteen 100- by 550-mm 

openings were cut in each 1.2-m-wide by 2.4-m-long by 

19-mm-thick panel to accommodate wood specimens used in 

the laboratory-to-field correlation studies. This study was 

intended to correlate thermal-induced degradation of FRtreated plywood in the field to matched FR-thermaldegradation rates derived in the laboratory (Barnes and 

others 1993). 

The study variables were exposure location (Madison, Wisconsin, or Starkville, Mississippi), roof shingle color (black 

or white), and structure moisture content (heavily humidified 

or dry). 

Recording of Temperatures 

To assess the effect of shingle color, the exposure structures 

were roofed with black or white CertainTeed XT–25 (CertainTeed Corp., Blue Bell, PA) fiberglass shingles weighing 

106 kg/square. The black and white shingles had reflectance 

values of 3.4% and 26.1%, respectively. Both black and 

white shingles had an emissivity rating of 0.91. These shingles were essentially identical to those used in Champaign, 

Illinois, to study the behavior of attics constructed and ventilated in various ways (Rose 1992). Two WI structures had 

white shingles; the remaining three WI structures and all five 

MS structures had black shingles. 

Three of the five WI exposure structures were each instrumented with nine type-T thermocouples placed at various 

locations within the structure (Fig. 2). These structures were 

(1) a black-shingled structure that was not ventilated or 

humidified, (2) a black-shingled structure that was unventilated and artificially humidified from April through October 

to maintain >85% relative humidity for most of the diurnal 

cycle, and (3) a white-shingled structure that was not ventilated or humidified. In Mississippi, all five structures were 

instrumented with thermocouples as shown in Figure 2. Two 

MS structures were humidified using a cold steam atomizing 

humidifier system such that the relative humidity was maintained at >85% for most of the diurnal cycle. The interiors of 

the other three MS structures were kept dry. 

The location and function of each thermocouple are described in Table 1. The thermocouples attached to the top ply 

of the roof sheathing (T3 and T4) were monitored because, 

theoretically, small roof systems such as the ones we tested 

have been reported to remain cooler than large roof structures since air flow heats as it travels across the roof surface. 

Rose (1992) reported the effects of such a phenomenon on 

sheathing temperatures for a 9.2-m-wide roof system compared with a 12.8-m-wide system. The position of thermocouple T7 allowed us to correlate rafter and sheathing temperatures. Thermocouple T8 acted as the external reference 

thermistor, with a rated accuracy of +0.2°C between −33°C 

and 48°C. Overall, the data from the thermocouples allowed 

us to correlate the roof temperatures of wood materials in 

various locations in a wood roof system with solar loads. 

Solar loads were monitored by the U.S. Weather Service at 

Mississippi State University in Starkville, Mississippi, and at 

the Dane County Regional Airport in Madison, Wisconsin. 

To collect and record the temperature data at each location 

(Wisconsin and Mississippi) from each thermocouple location, two Campbell–Scientific (Logan, UT) model CR10 

dataloggers and two model AM416, 32-channel multiplexers 

Figure 1—Exposure structures at Mississippi Forest 

Products Laboratory, Mississippi State University, 

Starkville, Mississippi. 
4 

Table 1—Location and function of thermocouples in exposure structuresa 

Thermocouple Location Measurement 

T0 Central, along back (north) wall Interior attic air temperature, 1 m above floor 

T1 Central, along back (north) wall Interior attic air temperature, 2 m above floor 

T2 Central, along back (north) wall Exterior air temperature, 2 m above grade 

T3 Attached to top ply of plywood roof sheathing below 

roofing felt at 1/3 the rafter span, approximately 

1.2 m from north (ridge) wall 

Temperature of top ply of sheathing toward north wall 

T4 Attached to top ply of plywood roof sheathing below 

roofing felt at 1/3 the rafter span, approximately 

1.2 m from south (eave) wall 

Temperature of top ply of sheathing toward south 

wall 

T5 Attached to bottom ply of plywood roof sheathing at 

1/3 the rafter span from the north (ridge) wall 

Temperature of bottom ply of sheathing toward north 

wall 

T6 Attached to bottom ply of plywood roof sheathing at 

1/3 the rafter span from the south (eave) wall 

Temperature of bottom ply of sheathing toward south 

wall 

T7 Center of rafter at midspan Correlation of rafter and sheathing temperatures 

T8 Datalogger External reference thermistor 

a

Additional detail is shown in Figure 2. 

~

3:12 pitch

Specimen

Roof felt

Plywood

sheathing T7

T1

T0

Shingle

T3

T5 T8

Embedded

inside

rafter

~

North

38 by

140 mm

rafter

T6 T4

Specimen

~

Datalogger

T8

T5 T3

Shingles Roof felt

Plywood

Rafters

T2

1.5 m

2.4 m

Test specimen

150 mm

Figure 2—Schematic cross section of instrumented field exposure structure slowing location of thermocouples 

(T0–T8) and channels for datalogger–multiplexer. 
5 

were used; one set (datalogger plus multiplexer) was used in 

Wisconsin and the other in Mississippi. The dataloggers had 

a reported accuracy of 0.2% over the service temperature 

range of −55°C to 85°C. 

At each location, the datalogger and multiplexer were placed 

in a weather-sealed box located inside the middle structure of 

the five structures and located on a side wall approximately 

1.83 m above the floor. Temperature data were collected 

every 5 min for each structure, and the datalogger was programmed to calculate and record hourly average temperatures. Each week, the hourly data were downloaded and 

saved using a laptop computer. The set-up of the datalogger 

and laptop computer in Mississippi is depicted on the cover 

of this report. The Wisconsin set-up was nearly identical 

and was previously described in detail by Winandy and 

Beaumont (1995). 

Measurement of Moisture Content 

At the Wisconsin site, moisture content was measured periodically at irregular intervals using an electrical resistance 

moisture content meter. The observations were collected 

during the day over the course of several years during all 

seasons. In Mississippi, moisture content was measured every 

2 weeks over a 3-year period in four of the five exposure 

structures, except for one 41⁄2-month period from late 

September 1998 to early February 1999. 

Results and Discussion 

The fact that the field structures were neither ventilated nor 

insulated means that the thermal data hereafter reported are 

truly indicative only of such constructions. Larger structures 

might theoretically experience slightly higher temperatures, 

but to exactly what degree is unknown (Rose 1992). Finally, 

because the attic floors were not insulated and not heated or 

cooled, as would probably be the case in a traditional lightframed wood structure, the cooler floors would be expected 

to subtly affect radiation exchange between the attic and 

underlying areas. However, we believe that much practical 

information can be learned from studying these field structure exposure temperature data. 

We experienced thermocouple and multiplexer–datalogger 

problems in the WI heavily humidified (wet) black-shingled 

structure from January 1 to June 14 in 1996. We substituted 

the data from the WI dry black-shingled structure for this 

period because the dry and wet black-shingled structures in 

Wisconsin were found to have experienced very similar 

winter-to-spring temperatures in other years. 

Sheathing Temperatures 

Top- and bottom-of-sheathing temperatures were monitored 

at the one-third and two-third points in the roof, midway 

between the eaves and the ridge. In both the MS and WI 

structures, the difference in recorded hourly temperatures 

between the two top-of-sheathing thermocouples (one-third 

and two-third span) seldom exceeded 1°C. This same <1°C 

difference was also found for the two bottom-of-sheathing 

thermocouples. The small difference in temperature between 

these two matched locations across the span of the structure 

shows that little practical difference really existed in the 

structures. This might be related to the small size of the test 

structures or their lack of ventilation. Rose (1992) found that 

increased ventilation in pitched, cathedral ceiling systems 

increased the across-the-span temperature differential. However, in a comparison of vented and unvented flat-roof systems, Rose (1995) found few differences in sheathing temperature between the eaves and the ridge. Our small 

difference in temperatures across the length of the roof span 

seems to confirm that few real differences exist in sheathing 

temperature between the eaves and the ridge. Accordingly, 

the two top-of-sheathing and two bottom-of-sheathing temperatures were averaged, and the average hourly value is 

reported. 

Exceedance Temperatures 

For the WI structures, the annual number of hours that the 

thermocouples recorded temperatures beyond various temperature limits were compiled into 5°C temperature bins. 

These 5°C bins (0°C to <5°C, 5°C to <10°C, ..., 70°C to 

75°C) are hereafter defined as “exceedance temperatures.” 

The value reported as the exceedance temperature for 70°C 

is thus the number of hours the temperature at that thermocouple location equaled or exceeded 70°C, but is less than 

75°C. Annual exceedance temperatures for the dry and wet 

black-shingled structures and dry white-shingled structure in 

Wisconsin, from 1992 to 1999, are given in Appendix A. 

Annual exceedance temperatures for the MS structures, from 

1996 to 1999, are given in Appendix B. The exceedance 

temperature data were averaged over their 8- or 4-year history to produce an annualized roof temperature history for 

each configuration. 

Maximum Temperatures 

For the 4-year study at the Mississippi exposure site, maximum “1-h average” temperatures recorded for black-shingled 

roofs in dry structures were 78°C and 63°C for the top and 

bottom plies of the plywood roof sheathing, respectively, and 

58°C for the rafter. The maximum temperatures recorded for 

the matched WI structures were 75°C, 59°C, and 54°C, 

respectively. MS and WI black-shingled structures showed 

only small differences (3°C to 4°C) in maximum record 

temperatures. 

The maximum temperatures recorded for the WI whiteshingled structure over the 8-year period were 64°C, 53°C, 

and 49°C for the top and bottom plies of the roof sheathing 

and the rafter, respectively. This clearly shows that the use 

of white shingles, as opposed to black shingles, can 
6 

dramatically lower the maximum temperatures—by 5°C to 

11°C—in wood materials used in roof systems. 

The maximum temperatures recorded in the 4-year Mississippi study for black-shingled roofs in heavily humidified 

structures were cooler than those for matched dry structures. 

For the wet black-shingled MS structures, maximum temperatures for the top and bottom plies of the roof sheathing 

and the rafter were 74°C, 58°C, and 54°C, respectively. The 

maximum temperatures of black-shingled roofs in heavily 

humidified structures in the 4-year Wisconsin study were 

cooler than those for matched dry WI structures. For the wet 

black-shingled WI structures, maximum temperatures for the 

top and bottom plies of the roof sheathing and the rafter were 

74°C, 58°C, and 52°C, respectively. The maximum temperatures of wet MS and dry and wet WI structures were virtually 

identical. Daily 1-h maximum temperatures and annualized 

roof temperature data for Wisconsin exhibited similar values 

and trends to previously reported data from a 3-year study in 

Wisconsin (Winandy and Beaumont 1995). 

Annual Temperature Trends 

The average 8- or 4-year temperature histories for each 

thermocouple in each exposure structure are plotted for the 

WI structures in Figures 3 to 5 and for the MS structures in 

Figures 6 and 7. Note the general similarity in relative form 

of the exceedance temperature distributions between each 

exposure site, roof color, and attic humidity configuration. 

As expected, the MS structures experienced many more 

hours of exposure to high air temperatures than did the WI 

structures. However, although air temperatures were often 

warmer in Mississippi than in Wisconsin, the differences in 

annual maximum temperatures of the top and bottom of the 

plywood roof sheathing were very similar. We observed that 

the higher portions of the roof sheathing temperature histories were clearly controlled by solar radiation and not the 

outside air temperature (Figs. 3 to 7), which reaffirms the 

earlier observations of Winandy and Beaumont (1995) and 

the predictions of the TenWolde (1997) model. Figures 3 to 

7 also show how internal rafter temperature is nearly coincident with inside attic air temperature and how both track 

relatively closely with outside air temperature. Thus, although solar radiation may control sheathing temperature, 

attic air space or rafter temperature is strongly influenced by 

outside air temperatures during most of the year. 

Figures 8 to 11 show a direct comparison of temperatures 

recorded by individual thermocouples for each building 

configuration. Note that for both Mississippi and Wisconsin, 

the wet (heavily humidified) roof systems were generally 

similar in temperature to dry roof systems except during the 

hottest days or the highest portions of the temperature range. 

In the high temperature range, the thermocouples in nearly 

every location within the wet MS structures were usually 3°C 

to 4°C cooler than matched thermocouples in the dry MS 

structures. We believe that this was caused by evaporative 

cooling of the sheathing and rafter lumber during those 

warmest periods of each hot day. Although both the MS and 

WI wet structures experienced this same characteristic 

“evaporative cooling,” the matched wet and dry MS structures seemed to experience an even more pronounced deviation in thermocouple temperatures. We expect that this occurred because Mississippi has a warmer, more humid 

climate, and the MS exposure structures were subject to 

longer periods in the warmer, more humid temperature range, 

1

10

100

1000

10000

Average hours/year

0 10 20 30 40 50 60 70 80

 Exceedence temperature (oC)

Rafter

Top ply Bottom ply

Inside air Outside air

WI, black, dry

Figure 3—Annualized 8-year temperature history for dry 

black-shingled structure in Wisconsin. 

1

10

100

1000

10000

Average hours/year

0 10 20 30 40 50 60 70 80

 Exceedence temperature (oC)

Rafter

Top ply Bottom ply

Inside air Outside air

WI, black, wet

Figure 4—Annualized 4-year temperature history for wet 

black-shingled structure in Wisconsin. 

1

10

100

1000

10000

Average hours/year

0 10 20 30 40 50 60 70 80

 Exceedence temperature (oC)

Rafter

Top ply Bottom ply

Inside air Outside air

WI, white, dry

Figure 5—Annualized 8-year temperature history for dry 

white-shingled structure in Wisconsin. 
7 

where measurable “evaporative cooling” would be more 

likely. 

The warmer climate of Mississippi is readily apparent in the 

plot of the annualized 8- or 4-year average temperatures 

(Fig. 12a). Note that the temperature measured by each 

thermocouple was generally higher (by 10°C to 14°C) in the 

MS structures compared with the WI structures. Furthermore, 

temperatures of wet and dry structures were generally similar, except for the previously discussed deviation at the highest temperatures (Fig. 12b). In both the MS and WI 

structures, the maximum plywood sheathing, rafter, and 

internal attic air temperatures during the monitoring periods 

were more similar than dissimilar, as earlier claims had 

suggested (ASTM 1988). 

The minimum temperatures reveal the real difference in 

climatic influences for Mississippi and Wisconsin (Fig. 12c). 

Note that the annual minimum temperatures of wood components in WI structures (–35° to –40°C) were as much as 20°C 

colder than the minimum temperatures of MS structures 

(–20°C). Also note that the minimum temperatures of WI 

Rafter

Top ply Bottom ply

Inside air Outside air

MS, black, dry

1000

10000

Average hours/year

1

10

100

0 10 20 30 40 50 60 70 80

 Exceedence temperature (oC)

Figure 6—Annualized 4-year temperature history for 

dry black-shingled structure in Mississippi. 

0 10 20 30 40 50 60 70 80

 Exceedence temperature (oC)

1

10

100

1000

10000

Average hours/year

Rafter

Top ply Bottom ply

Inside air Outside air

MS, black, wet

Figure 7—Annualized 4-year temperature history for 

wet black-shingled structure in Mississippi. 

1

10

100

1000

10000 Average hours/year

0 10 20 30 40 50 60 70 80

 Exceedence temperature (oC)

WI, white, dry

WI, black, wet

WI, black, dry

MS, black, wet

MS, black, dry

Attic

Figure 8—Attic air temperature history for test 

structures. 

1

10

100

1000

10000 Average hours/year

0 10 20 30 40 50 60 70 80

 Exceedence temperature (oC)

WI, white, dry

WI, black, wet

WI, black, dry

MS, black, wet

MS, black, dry

Roof sheathing, top

Figure 9—Air temperature history for top surface of 

plywood roof sheathing. 

1

10

100

1000

10000 Average hours/year

0 10 20 30 40 50 60 70 80

 Exceedence temperature (oC)

WI, white, dry

WI, black, wet

WI, black, dry

MS, black, wet

MS, black, dry

Roof sheathing, bottom

Figure 10—Air temperature history for bottom surface 

of plywood roof sheathing. 

1

10

100

1000

10000 Average hours/year

0 10 20 30 40 50 60 70 80

 Exceedence temperature (oC)

WI, white, dry

WI, black, wet

WI, black, dry

MS, black, wet

MS, black, dry

Internal roof rafter

Figure 11—Air temperature history for internal rafters. 
8 

 Figure 12—Average, maximum, and minimum 8- or 4-year temperatures for exposure structures. 

(a) 8- or 4-year averages

0 

5 

10 

15 

20 

25 

30 

0 

-45 

Inside Outside Sheathing 

top

Sheathing 

bottom 

Rafter

(c) 8- or 4-year minimums

-40 

-35 

-30 

-25 

-20 

-15 

-10 

-5 

10

5

0

(b) 8- or 4-year maximums

10 

20 

30 

40 

50 

60 

70 

80 

90 

WI, white, dry

WI, black, dry

WI, black, wet

MS, black, dry

MS, black, wet

Temperature (°C) 
9 

black- and white-shingled structures (Fig. 12c) were very 

similar to each other, whereas the maximum temperatures of 

these structures were very different from each other 

(Fig. 12b). 

Annual outside air temperatures in Madison, Wisconsin, 

were distinctly bimodal. Thermocouple T2 readings showed 

two distinct peaks at 10°C to 15°C and –5°C to 0°C, with 

noticeably fewer values in the 5°C to 10°C range (Tables 2 

to 4). The other thermocouple readings (attic air, top and 

bottom of plywood roof sheathing, and rafter) also showed 

signs of bimodality, but not as obviously. These findings are 

evident in the data for the WI structures by individual year 

and location–interior humidity configuration (Appendix A). 

The temperature histories of all thermocouple locations in the 

MS structures were unimodal (Appendix B). The Mississippi 

data did not exhibit the bimodal nature of the Wisconsin 

data. Tables 5 and 6 show the unimodal nature of the thermal 

loads for the MS structures. 

Peak Temperature Trends 

The temperatures achieved at each thermocouple location 

during the hottest 7-consecutive-day period over the 8- or 

4-year history of each exposure structure are shown in 

Figures 13 and 14; the influence of exposure site and attic 

humidity during this time is shown in Figure 15. The individual “peak” temperatures recorded for both the dry blackshingled and dry white-shingled WI structures during the 

8-year exposure period were similar to those recorded previously for a 3-year exposure study (Winandy and Beaumont 

1995). Although the wood components under the white 

roofing material were much cooler on “peak” days than those 

under the black roofing material, the differences between 

sheathing temperatures of the dry black-shingled and dry 

white-shingled WI attics were minimal. 

Table 2—Eight-year average times at given 

temperatures for WI dry, black-shingled structure 

Time (h) at given temperature at various locations 

Structure Roof sheathing Temper–

ature 

(°C) Inside Outside Top Bottom Rafter 

–40 0 –– 1 1 1 

–35 7 6 9 8 7 

–30 13 15 18 14 13 

–25 48 51 71 55 51 

–20 149 162 172 156 149 

–15 256 314 289 267 259 

–10 548 622 595 571 561 

–5 1,063 1,220 1,057 1,064 1,062 

0 1,276 1,340 1,216 1,246 1,269 

5 987 990 948 967 977 

10 1,034 1,131 1,003 1,030 1,035 

15 1,063 1,297 964 1,038 1,050 

20 846 1,040 652 771 834 

25 509 486 385 480 514 

30 399 88 308 365 402 

35 322 4 258 322 322 

40 186 –– 225 240 194 

45 55 –– 210 134 62 

50 5 –– 168 35 6 

55 –– –– 121 4 –– 

60 –– –– 70 –– –– 

65 –– –– 23 –– –– 

70 –– –– 5 –– –– 

75 –– –– 0 –– –– 

Table 3—Four-year average times at given 

temperatures for WI wet, black-shingled structure 

Time (h) at given temperature at various locations 

Structure Roof sheathing Temper–

ature 

(°C) Inside Outside Top Bottom Rafter 

–40 1 –– 2 1 1 

–35 7 6 9 8 8 

–30 12 14 14 12 11 

–25 43 49 61 48 43 

–20 138 161 160 151 142 

–15 240 282 272 246 239 

–10 523 554 568 555 532 

–5 1,073 1,261 1,081 1,071 1,070 

0 1,246 1,352 1,175 1,208 1,246 

5 961 958 935 942 943 

10 1,056 1,164 1,051 1,038 1,033 

15 1,090 1,282 978 1,038 1,061 

20 911 1,070 668 824 916 

25 565 501 400 501 560 

30 424 105 306 383 428 

35 325 7 262 321 340 

40 134 –– 230 255 170 

45 17 –– 209 136 27 

50 1 –– 172 26 2 

55 –– –– 128 3 –– 

60 –– –– 65 –– –– 

65 –– –– 20 –– –– 

70 –– –– 4 –– –– 

75 –– –– –– –– –– 
10 

As discussed previously in this report, wood components in 

the matched WI and MS structures experienced similar annual maximum temperatures, but MS structures were exposed to those peak temperature ranges for more hours each 

day. This result is clearly evident in the comparison of temperatures recorded over the hottest 7-consecutive-day period 

over the 8- and 4-year histories of the respective Wisconsin 

and Mississippi exposure sites (Figs. 13 and 14, respectively). The same scenario is evident in the temperature 

histories of wood components in the heavily humidified MS 

and WI structures. Like the temperatures of the dry structures, the individual annual peak temperatures of the wet 

black-shingled structures in Wisconsin (Fig. 13) and Mississippi (Fig. 14) were similar, but the daily peak temperatures 

in the MS structures were higher. These results suggest that 

the benefits and limitations of attic ventilation during warm 

summer periods are similar regardless of whether the buildings are located in the North or the South. 

Many important trends can be summarized by analyzing the 

wood component and attic air temperatures over the hottest 

7-consecutive-day period over the Wisconsin and Mississippi 

histories. Attic air temperatures were clearly higher in the 

MS structures than in the WI structures (Fig. 15). The effect 

of evaporative cooling is illustrated by the fact that attic air 

temperature in the MS wet black-shingled structure was 

similar to that in the WI dry black-shingled structure, and 

attic air temperature in the WI wet black-shingled structure 

was similar to that in the WI dry white-shingled structure. On 

the contrary, the top-of-sheathing temperatures of the dry and 

wet structures in both Mississippi and Wisconsin were very 

similar (Fig. 15). This seems to reinforce the idea that sheathing temperatures, especially temperatures at the top of the 

sheathing, are primarily controlled by solar radiation. 

The temperatures of the bottom of the plywood sheathing fell 

between the temperatures recorded for the attic air and the 

top of the sheathing (Fig. 15). We observed that bottom-ofsheathing temperatures followed a thermal history that 

Table 4—Eight-year average times at given 

temperatures for WI dry, white-shingled structure 

Time (h) at given temperature at various locations 

Structure Roof sheathing Temper–

ature 

(°C) Inside Outside Top Bottom Rafter 

–40 0 –– 2 1 1 

–35 7 6 9 8 7 

–30 12 15 18 14 13 

–25 47 50 74 55 50 

–20 143 161 177 159 150 

–15 258 308 296 273 262 

–10 559 614 614 588 574 

–5 1,074 1,213 1,111 1,097 1,085 

0 1,308 1,333 1,248 1,288 1,307 

5 993 996 976 985 987 

10 1,058 1,145 1,045 1,062 1,057 

15 1,102 1,278 1,003 1,061 1,086 

20 888 1,061 700 821 868 

25 546 492 408 490 538 

30 428 91 318 397 427 

35 266 3 271 287 266 

40 73 –– 227 148 82 

45 6 –– 161 31 8 

50 –– –– 83 2 –– 

55 –– –– 23 –– –– 

60 –– –– 5 –– –– 

65 –– –– –– –– –– 

70 –– –– –– –– –– 

75 –– –– –– –– –– 

Table 5—Four-year average times at given 

temperatures for MS dry, black-shingled structure 

Time (h) at given temperature at various locations 

Structure Roof sheathing Temper–

ature 

(°C) Inside Outside Top Bottom Rafter 

–40 –– –– –– –– –– 

–35 –– –– –– –– –– 

–30 –– –– –– –– –– 

–25 –– –– –– –– –– 

–20 1 1 8 4 2 

–15 13 14 29 15 13 

–10 55 65 107 72 57 

–5 202 243 331 258 215 

0 552 591 609 562 544 

5 882 1,080 857 866 870 

10 1,078 1,273 1,043 1,048 1,057 

15 1,150 1,423 1,159 1,108 1,139 

20 1,596 1,925 1,398 1,532 1,563 

25 1,070 1,193 641 866 1,036 

30 639 783 421 581 647 

35 494 176 355 482 493 

40 507 –– 348 399 466 

45 398 –– 338 418 445 

50 130 –– 284 356 211 

55 2 –– 310 190 11 

60 –– –– 272 13 –– 

65 –– –– 194 –– –– 

70 –– –– 64 –– –– 

75 –– –– 2 –– –– 
11 

seemed to be partially controlled by both the attic air and 

top-of-sheathing temperatures. Rafter temperatures also 

appeared to mirror the thermal history of bottom-ofsheathing temperatures. Rafter temperatures in the wet blackshingled MS structure fell between those of the MS dry 

black-shingled and WI dry black-shingled structures 

(Fig. 15). These observations reinforce the idea that the 

bottom-of-sheathing and internal rafter temperatures are 

jointly influenced by outside air and attic air temperatures 

and by solar radiation. 

As discussed previously in this report, engineering design 

standards for wood (AF&PA 1997) require a strength property adjustment for sustained exposures above 37.8°C and 

greater adjustment for prolonged exposures up to 65.6°C. 

Average annualized exposures at various critical temperatures were derived using a nonparametric analysis. These 

values (Table 7) show the relative time the various wood 

building components spent in three AF&PA temperature 

regimes: (1) ≥37.8°C but <51.7°C, (2) ≥51.7°C but <65.6°C, 

and (3) ≥65.6°C. The data show that roof plywood sheathing 

and roof rafters are in these important temperature ranges for 

a significant portion of time. Recently derived models for the 

residual serviceability of untreated wood roofing material 

have shown that such thermal loading might account for a 

4% loss in strength for each 10 years of exposure in Madison, Wisconsin (Winandy 1998). 

Moisture Content 

Rose (1992) reported that when a good vapor barrier was 

maintained between warm living spaces and cooler attics, the 

moisture content (MC) of wood components used in flat- or 

cathedral-ceiling attics ranged from 8% to 22%, averaged 

between 13% and 15%, and was higher than 18% for less 

than 20 to 50 hours per year. These findings were similar 

regardless of whether the roof systems were ventilated or 

unventilated. However, Rose found that when the ceiling 

vapor barrier was broken, lumber in unventilated cathedral 

roof cavities could have more than 30% moisture content for 

more than 200 h/year. In our study, none of the MC measurements taken at the Wisconsin site was higher than 20% or 

lower than 6%. In winter, MC tended to range from 13% to 

16% and in summer, from 8% to 12%. At the Mississippi 

site, wood MC was lowest during summer and highest during 

winter. In dry roof systems, sheathing MC varied from 1.5% 

in summer to 7.5% in winter; in artificially humidified roof 

systems, sheathing MC varied from 4% in summer to 17% in 

winter (Fig. 16). Thus, the results from the WI structures, 

which were not humidified during cold weather periods, and 

the MS structures, which were humidified all year long, 

affirm the trends in wood MC previously reported by Rose 

(1992). 

Concluding Remarks 

The results of this research study are summarized as follows: 

• The annual 1-h maximum temperatures of various wood 

components were similar in Mississippi and Wisconsin 

roof systems; these temperatures were only 3°C to 4°C 

higher in the MS structures. 

• Although the annual maximum and the form of the recorded exceedance temperatures were similar in the MS 

and WI exposure structures, the MS structures experienced 

temperatures in the higher range for many more hours per 

year compared to matched WI structures. Temperatures of 

wood components in the MS structures were generally 5°C 

to 10°C warmer than those of matched WI structures. 

• Black-shingled roof systems tended to be 5°C to 10°C 

warmer on sunny afternoons compared with white-shingled 

systems. 

• Moisture content of plywood roof sheathing in dry MS 

structures varied from 1.5% to 7.5% between summer and 

winter; moisture content of sheathing in wet (heavily humidified) MS structures varied from 4% to 17%. Moisture 

content of sheathing in dry WI structures varied from 6% 

to 13%. 

Table 6—Four-year average times at given 

temperatures for MS wet, black-shingled structure 

Time (h) at given temperature at various locations 

Structure Roof sheathing Temper–

ature 

(°C) Inside Outside Top Bottom Rafter 

–40 –– –– –– –– –– 

–35 –– –– –– –– –– 

–30 –– –– –– –– –– 

–25 –– –– –– –– –– 

–20 –– 1 5 1 –– 

–15 8 14 14 11 9 

–10 23 65 97 36 26 

–5 229 243 316 254 232 

0 578 591 601 568 559 

5 915 1,080 871 867 887 

10 1,130 1,273 1,032 1,058 1,079 

15 1,213 1,423 1,160 1,130 1,169 

20 1,686 1,925 1,425 1,581 1,632 

25 1,028 1,193 686 961 1,074 

30 625 783 456 646 652 

35 557 176 378 473 524 

40 480 –– 366 471 508 

45 283 –– 324 430 339 

50 14 –– 312 256 78 

55 –– –– 312 22 –– 

60 –– –– 250 –– –– 

65 –– –– 145 –– –– 

70 –– –– 18 –– –– 

75 –– –– –– –– –– 
12 

20

30

40

50

60

70

80

July 1999

(a) WI, black, dry

24 25 28 26 30 31 27 29

Temperature (oC)

20

30

40

50

60

70

80

(b) WI, black, wet

20

30

40

50

60

(c) WI, white, dry

70

80

Rafter

Top ply Bottom ply

Inside air Outside air

Figure 13—Temperatures at each thermocouple location during 7 hottest consecutive days in 8-year 

exposure of WI structures. 
13 

• Temperatures at the top of the roof sheathing were controlled by solar gain, not outside air or attic air temperatures. 

• Temperatures at the bottom of the roof sheathing were 

usually controlled by solar gain, except on a few of the 

hottest days, when sheathing temperatures were also influenced by outside air or attic air temperatures. 

• Rafter temperatures were usually controlled by attic air 

temperatures, except on a few of the hottest days, when 

they were also influenced by solar radiation. 

• On hot days in heavily humidified structures, evaporative 

cooling is responsible for lower temperatures in plywood 

sheathing and wood rafters. 

• The major difference in the temperature of wood components used in attics in the northern exposure (Wisconsin) 

compared with those used in the southern exposure (Mississippi) was in minimum temperatures, which were as 

much as 20°C lower in the WI structures. 

• Annual outside air temperature is bimodal in Wisconsin, 

with two distinct peaks at 10°C to 15°C and −5°C to 0°C. 

Annual outside air temperature is unimodal in Mississippi, 

averaging between 10°C and 15°C. 

20

30

40

50

60

70

80

Temperature (oC)

20

30

40

50

60

70

80

June 1998

(a) MS, black, dry

20 21 24 22 26 27 23 25

Inside air Top ply Rafter Outside air Bottom ply (b) MS, black, wet

Figure 14—Temperatures at each thermocouple location during 7 hottest consecutive days in 4-year exposure 

of MS structures. 
14 

Rafter

Top ply Bottom ply

Inside air Outside air (a) Attic air

20

30

40

50

60

70

80

20

30

40

50

60

70

80

1 2 3 4 5 6 7 8

Day

(d) Rafter

MS, black, wet

WI, white, dry MS, black, dry

WI, black, dry WI, black, wet

20

30

40

50

60

70

80

20

30

40

50

60

70

80 (c) Sheathing bottom

Temperature (oC)

(b) Sheathing top

Figure 15—Influence of exposure site and attic humidity during 7 hottest consecutive days in 

exposure period. 
15 

Average moisture content (%)

2

6

10

14

18

22

Mar15

Mar30

Apr10

Apr25

May23

Jun26

Jul25

Aug31

Oct06

Nov22

Jan09

Feb27

Apr25

Jun11

Aug09

Sep23

Nov04

Dec05

Jan23

Feb27

Apr15

Jul09

Aug19

Dec02

Feb18

Mar27

Apr29

Sep29

Feb19

Apr23

Jun25

Aug02

Sep09

MS, black, wet

MS, black, dry

Average moisture content (%)

Mar15Mar31

Apr18

May18

Jun26

Aug09Sep21

Nov08

Jan09

May19

Jul22

Mar14

Sep23

Nov11

Dec17

Feb13

Apr15

Nov11

Feb10

Mar27

Jun24

Feb19

May06

Jul12

Aug30

1

2

3

4

5

6

7

8

 Figure 16—Moisture content history for dry and wet MS black-shingled structures. 
16 

Acknowledgments 

The authors would like to acknowledge the financial assistance of the USDA Competitive Grants program (grant no. 

93–02444) and the New Jersey Department of Community 

Affairs. We also acknowledge the technical assistance of 

Louis Watson at Mississippi State University and Mike 

Grambsch and Earl Geske at Forest Products Laboratory, 

who monitored and programmed the temperature datalogging 

equipment. Rita Simonsen of the Forest Products Laboratory 

archived 8 years worth of field data. Finally, we wish to 

thank the CertainTeed Corporation for donation of the roofing materials used for the outdoor simulated-attic structures. 

References 

AF&PA. 1997. National design specification for wood 

construction. An American National Standards Institute/American Forest and Paper Association Standard. 

ANSI/AF&PA NDS–1997. Washington, DC: American 

Forest & Paper Association.174 p. 

APA. 1989. Fire-retardant-treated plywood: Prediction of 

performance. Tacoma, WA: American Plywood Association. 

ASTM. 1988. Effect of fire retardant treatments (FRT) on 

the strength properties of wood. In: Minutes of workshop; 

1988 April 26; Madison, WI: ASTM D7.06.04 Section: Fire 

performance of wood. U.S. Department of Agriculture, Forest Service, Forest Products Laboratory. 7 p. 

ASTM. 1999. Standard practice for calculating bending 

strength design adjustment factors for fire-retardant-treated 

plywood roof sheathing. ASTM Annual Book of Standards, 

ASTM D6305–98. West Conshohocken, PA: American 

Society for Testing and Materials. 

Barnes, H.M.; Winandy, J.E.; Conners, T.E. 1993. Laboratory/field correlations for FRT plywood. USDA National 

Research Initiative, competitive grant proposal for natural 

resources and the environment, Grant no. 93–02444. Washington, DC: U.S. Department of Agriculture, National Research Initiative. 

Blackenstowe, D.E. 1987. Comparison of white versus black 

surfaces for energy conservation. In: Proceedings, 

8th conference on roofing technology; 1897 April 16–17. 

Gaithersburg, MD: National Bureau of Standards. 

Heyer, O.C. 1963. Study of temperature in wood parts of 

houses throughout the United States. Res. Note FPL–RN–

012. Madison, WI: U.S. Department of Agriculture, Forest 

Service, Forest Products Laboratory. 

Table 7—Duration of exposure of each test structure in hightemperature exposure ranges in current building designa 

Site Shingle Humidity 

Sheathing 

or rafter 

location 

≥37.8°C 

but 

<51.7°C 

≥51.7.°

C but 

<65.6°C ≥65.6°C 

WI Black Dry Top 608 302 23 

 Bottom 526 20 — 

 Rafter 389 2 — 

 Wet Top 609 308 20 

 Bottom 537 13 — 

 Rafter 335 1 — 

 White Dry Top 546 73 — 

 Bottom 292 1 — 

 Rafter 190 — — 

MS Black Dry Top 932 790 234 

 Bottom 1,160 428 — 

 Rafter 1,232 122 — 

 Wet Top 968 783 144 

 Bottom 1,195 176 — 

 Rafter 1,148 15 — 

a

AF&PA 1997. 
17 

Lebow, P.K.; Winandy, J.E. 1999. Verification of kineticsbased model for long-term effects of fire-retardants on bending strength at elevated temperatures. Wood and Fiber 

Science. 31(1): 49–61. 

LeVan, S.L.; Collet, M. 1989. Choosing and applying fireretardant-treated plywood and lumber for roof designs. Gen. 

Tech. Rep. FPL–GTR–62. Madison, WI: U.S. Department 

of Agriculture, Forest Service, Forest Products Laboratory. 

11 p. 

NAHB. 1990. Home builders guide to fire retardant treated 

plywood: Evaluation, testing, and replacement. Washington, 

DC: National Research Center of the National Association of 

Home Builders. 65 p. 

NBS. 1979. Summer cooling and whole house ventilation. 

NBS special pub. 548. Reppart, M.H., ed. Gaithersburg, MD: 

National Bureau of Standards, U.S. Department of Commerce. 

Ozkan, E. 1993. Surface and inner temperature attainment of 

flat roof systems in hot–dry climate. Riyadh, Saudi Arabia: 

King Saud University, Riyadh. 

Rose, W.B. 1992. Measured values of temperature and 

sheathing moisture content in residential attic assemblies. In: 

Geshwiler, M., ed. Thermal performance of the exterior 

envelopes of building. In: Proceedings, ASHRAE/DOE/ 

BTECC conference; 1992 December 1–10; Clearwater 

Beach, FL. Atlanta, GA: American Society of Heating, Refrigerating, and Air-Conditioning Engineers: 379–390. 

Rose, W.B. 1995. Temperature and sheathing moisture 

content in residential attics. Unpub. rep., Champaign, IL: 

University of Illinois, Building Research Center. 

TenWolde, A. 1988. The FPL roof temperature model. In: 

Effects of fire retardant treatments on strength properties of 

wood; Executive summary, ASTM D7 workshop; 1988 

April. Madison, WI: U.S. Department of Agriculture, Forest 

Service, Forest Laboratory. 

TenWolde, A. 1997. FPL roof temperature and moisture 

model. Res. Pap. FPL–RP–561. Madison, WI: U.S. Department of Agriculture, Forest Service, Forest Products Laboratory. 

Wilkes, K.E. 1989. Model for roof thermal performance. 

Oak Ridge National Laboratory Rep. ORNL/CON–274. Oak 

Ridge, TN: Office of Scientific and Technical Information. 

Winandy, J.E. 1998. Using kinetics-based models to address 

serviceability concerns for fire-retardant-treated wood at 

elevated in-service temperatures. In: Proceedings, 5th World 

conference on timber engineering; 1998 August 16–21: 

Montreux, Switzerland. Lausanne, Switzerland: Swiss Federal Institute of Technology. 

Winandy, J.E. 2000. Serviceability modeling—Predicting 

and extending useful service life of FRT plywood roof 

sheathing. In: Proceedings, International Research Group for 

Wood Preservation, IRG/WP 00–20210, Stockholm, Sweden. 

Winandy, J.E.; Beaumont, R. 1995. Roof temperatures in 

simulated attics. Res. Pap. FPL–RP–543. Madison, WI: U.S. 

Department of Agriculture, Forest Service, Forest Products 

Laboratory. 

Appendix A—Exceedance 

Temperature Data for WI 

Structures 

The data in Tables 8 to 27 show exceedance temperature data 

for field exposure structures in Madison, Wisconsin, from 

1992 to 1999. 

Table 8—Exceedance temperatures in WI dry, 

black-shingled structure, 1992 

Time (h) at given temperature at various locations 

Structure Roof sheathing Temper–

ature 

(°C) Inside Outside Top Bottom Rafter 

−40 — — — — — 

–35 — — — — — 

–30 — — 12 3 — 

–25 32 25 32 33 35 

–20 56 67 60 58 52 

–15 172 183 244 196 176 

–10 496 539 558 526 516 

–5 1,230 1,453 1,238 1,250 1,243 

0 1,589 1,714 1,485 1,542 1,565 

5 1,035 961 1,023 1,023 1,036 

10 1,020 1,149 977 1,020 1,030 

15 1,075 1,427 935 1,017 1,032 

20 772 929 559 677 752 

25 467 305 369 445 487 

30 374 32 292 349 379 

35 310 — 258 297 314 

40 135 — 204 225 142 

45 21 — 204 104 25 

50 — — 158 19 — 

55 — — 103 — — 

60 — — 61 — — 

65 — — 12 — — 

70 — — — — — 

75 — — — — — 
18 

 

Table 9—Exceedance temperatures in WI dry, 

black-shingled structure, 1993 

Time (h) at given temperature at various locations 

Structure Roof sheathing Temper–

ature 

(°C) Inside Outside Top Bottom Rafter 

–40 — — — — — 

–35 — — — — — 

–30 — — 3 — — 

–25 34 17 66 50 38 

–20 143 152 183 154 144 

–15 278 385 277 280 277 

–10 592 703 642 631 603 

–5 1,014 1,165 1,030 1,022 1,026 

0 1,542 1,585 1,442 1,487 1,518 

5 881 875 816 848 872 

10 983 1,136 988 999 979 

15 1,104 1,283 975 1,061 1,084 

20 865 1,046 676 776 882 

25 532 381 396 496 530 

30 405 32 325 358 396 

35 276 — 265 330 289 

40 84 — 223 183 92 

45 25 — 209 63 28 

50 2 — 131 19 2 

55 — — 68 3 — 

60 — — 27 — — 

65 — — 13 — — 

70 — — 5 — — 

75 — — — — — 

Table 10—Exceedance temperatures in WI dry, 

black-shingled structure, 1994 

Time (h) at given temperature at various locations 

Structure Roof sheathing Temper–

ature 

(°C) Inside Outside Top Bottom Rafter 

–40 1 — 5 4 2 

–35 27 22 35 29 29 

–30 54 65 68 58 53 

–25 98 124 110 110 104 

–20 173 211 172 172 174 

–15 268 300 305 276 263 

–10 561 619 633 592 581 

–5 860 914 842 860 858 

0 986 1,088 999 998 984 

5 1,075 1,189 998 1,035 1,065 

10 1,045 1,134 1,012 1,044 1,052 

15 1,223 1,528 1,059 1,164 1,198 

20 832 1,007 663 765 832 

25 554 486 414 505 555 

30 444 69 314 388 432 

35 335 4 264 334 332 

40 186 — 246 260 204 

45 35 — 225 132 39 

50 3 — 183 31 3 

55 — — 129 3 — 

60 — — 59 — — 

65 — — 22 — — 

70 — — 2 — — 

75 — — 1 — — 

Table 11—Exceedance temperatures in WI dry, 

black-shingled structure, 1995 

Time (h) at given temperature at various locations 

Structure Roof sheathing Temper–

ature 

(°C) Inside Outside Top Bottom Rafter 

–40 — — — — — 

–35 — — — — — 

–30 2 — 8 5 3 

–25 55 45 95 66 56 

–20 204 188 250 217 204 

–15 330 402 331 345 337 

–10 591 828 625 604 593 

–5 1,078 1,174 1,032 1,057 1062 

0 1,187 1,172 1,127 1,161 1,202 

5 1,032 985 980 1,016 1,019 

10 902 1,000 860 897 906 

15 825 1,024 839 836 819 

20 923 1,109 761 827 914 

25 550 635 387 537 555 

30 413 187 325 343 410 

35 305 11 235 315 295 

40 242 — 219 244 250 

45 109 — 213 199 120 

50 12 — 170 78 15 

55 — — 134 13 — 

60 — — 115 — — 

65 — — 43 — — 

70 — — 11 — — 

75 — — — — — 

Table 12—Exceedance temperatures in WI dry, 

black-shingled structure, 1996 

Time (h) at given temperature at various locations 

Structure Roof sheathing Temper–

ature 

(°C) Inside Outside Top Bottom Rafter 

–40 2 — 6 3 3 

–35 24 22 28 26 24 

–30 32 44 32 31 29 

–25 82 86 125 92 84 

–20 235 287 256 245 236 

–15 316 435 337 318 327 

–10 672 712 721 702 684 

–5 1,154 1,337 1,094 1,131 1,147 

0 1,123 1,187 1,041 1,078 1,112 

5 828 872 884 850 815 

10 1,149 1,120 1,171 1,134 1,135 

15 1,081 1,206 867 1,030 1,097 

20 756 953 586 703 742 

25 430 459 366 421 436 

30 354 54 269 335 363 

35 326 10 248 318 331 

40 172 — 222 220 165 

45 48 — 203 131 — 

50 — — 157 16 — 

55 — — 91 — — 

60 — — 67 — — 

65 — — 13 — — 

70 — — — — — 

75 — — — — — 
19 

Table 13—Exceedance temperatures in WI dry, 

black-shingled structure, 1997 

Time (h) at given temperature at various locations 

Structure Roof sheathing Temper–

ature 

(°C) Inside Outside Top Bottom Rafter 

–40 — — — — — 

–35 — — — — — 

–30 6 — 9 6 5 

–25 40 53 65 46 46 

–20 146 162 181 152 145 

–15 229 270 255 241 235 

–10 521 623 611 544 543 

–5 1,213 1,385 1,185 1,216 1,218 

0 1,369 1,441 1,287 1,333 1,347 

5 934 837 915 909 927 

10 1,025 1,146 945 1,019 1,035 

15 996 1,339 989 1,005 986 

20 869 1,023 605 773 842 

25 496 418 372 483 498 

30 384 63 317 365 388 

35 304 — 252 306 295 

40 181 — 225 213 197 

45 41 — 192 124 47 

50 6 — 158 21 6 

55 — — 117 4 — 

60 — — 57 — — 

65 — — 18 — — 

70 — — 5 — — 

75 — — — — — 

Table 14—Exceedance temperatures in WI dry, 

black-shingled structure, 1998 

Time (h) at given temperature at various locations 

Structure Roof sheathing Temper–

ature 

(°C) Inside Outside Top Bottom Rafter 

–40 — — — — — 

–35 — — — — — 

–30 — — 3 — — 

–25 15 16 27 17 15 

–20 81 75 116 91 84 

–15 148 206 157 150 151 

–10 380 349 427 384 380 

–5 949 1,157 989 960 950 

0 1,278 1,339 1,230 1,254 1,274 

5 1,054 1,079 961 1,023 1,045 

10 1,169 1,286 1,185 1,164 1,159 

15 1,117 1,342 1,063 1,133 1,126 

20 918 1,167 690 848 882 

25 511 656 379 471 520 

30 420 88 296 393 438 

35 378 — 278 355 364 

40 272 — 243 298 287 

45 69 — 224 181 78 

50 1 — 204 38 7 

55 — — 169 — — 

60 — — 85 — — 

65 — — 27 — — 

70 — — 7 — — 

75 — — — — — 

Table 15—Exceedance temperatures in WI dry, 

black-shingled structure, 1999 

Time (h) at given temperature at various locations 

Structure Roof sheathing Temper–

ature 

(°C) Inside Outside Top Bottom Rafter 

–40 — — — — — 

–35 5 2 8 6 5 

–30 9 11 11 8 10 

–25 31 44 49 28 28 

–20 150 152 160 159 156 

–15 310 330 404 329 309 

–10 568 604 546 581 584 

–5 1,007 1,176 1,042 1,016 993 

0 1,134 1,195 1,113 1,117 1,147 

5 1,054 1,119 1,009 1,029 1,033 

10 980 1,079 888 960 986 

15 1,080 1,228 981 1,056 1059 

20 832 1,085 675 801 824 

25 532 550 394 479 534 

30 401 178 326 385 408 

35 344 7 261 322 352 

40 219 — 221 278 211 

45 91 — 208 139 106 

50 13 — 179 59 15 

55 — — 156 8 — 

60 — — 85 — — 

65 — — 34 — — 

70 — — 10 — — 

75 — — — — — 

Table 16—Exceedance temperatures in WI wet, 

black-shingled structure, 1996 

Time (h) at given temperature at various locations 

Structure Roof sheathing Temper–

ature 

(°C) Inside Outside Top Bottom Rafter 

–40 2 — 6 3 3 

–35 24 22 28 26 24 

–30 32 44 32 31 29 

–25 82 88 124 94 85 

–20 233 285 255 249 234 

–15 324 433 339 317 325 

–10 672 708 714 712 689 

–5 1,135 1,342 1,095 1,121 1,133 

0 1,129 1,191 1,037 1,067 1,113 

5 817 854 849 826 791 

10 1,086 1,098 1,156 1,057 1,050 

15 1,128 1,199 889 1,062 1,136 

20 785 913 612 740 810 

25 473 468 380 449 470 

30 377 123 276 340 381 

35 324 16 248 311 318 

40 151 — 219 232 176 

45 10 — 210 135 17 

50 — — 155 12 — 

55 — — 99 — — 

60 — — 51 — — 

65 — — 10 — — 

70 — — — — — 

75 — — — — — 
20 

Table 17—Exceedance temperatures in WI wet, 

black-shingled structure, 1997 

Time (h) at given temperature at various locations 

Structure Roof sheathing Temper–

ature 

(°C) Inside Outside Top Bottom Rafter 

–40 — — — — — 

–35 — — — — — 

–30 5 — 9 6 4 

–25 44 52 57 47 44 

–20 138 163 173 160 142 

–15 240 266 266 246 237 

–10 529 613 589 558 522 

–5 1,188 1,406 1,211 1,224 1,235 

0 1,377 1,428 1,265 1,301 1,348 

5 915 823 886 870 879 

10 977 1,143 955 983 952 

15 1,030 1,364 975 966 971 

20 940 1,033 642 825 977 

25 598 414 411 532 582 

30 425 55 302 386 437 

35 258 — 265 319 288 

40 87 — 216 209 128 

45 9 — 199 110 14 

50 — — 163 16 — 

55 — — 104 2 — 

60 — — 56 — — 

65 — — 12 — — 

70 — — 4 — — 

75 — — — — — 

Table 18—Exceedance temperatures in WI wet, 

black-shingled structure, 1998 

Time (h) at given temperature at various locations 

Structure Roof sheathing Temper–

ature 

(°C) Inside Outside Top Bottom Rafter 

–40 — — — — — 

–35 — — — — — 

–30 — — 3 1 

–25 16 15 25 21 15 

–20 82 74 113 93 89 

–15 146 201 155 154 149 

–10 369 353 431 386 373 

–5 992 1,141 1,010 984 961 

0 1,224 1,350 1,197 1,244 1,267 

5 1,020 1,066 958 994 1,014 

10 1,147 1,289 1,165 1,125 1,116 

15 1,136 1,345 1,072 1,119 1,107 

20 1,005 1,242 723 886 980 

25 592 614 394 493 602 

30 464 70 307 430 463 

35 400 — 268 335 404 

40 154 — 266 311 203 

45 13 — 216 162 17 

50 — — 187 22 — 

55 — — 167 — — 

60 — — 78 — — 

65 — — 22 — — 

70 — — 3 — — 

75 — — — — — 

Table 19—Exceedance temperatures in WI wet, 

black-shingled structure, 1999 

Time (h) at given temperature at various locations 

Structure Roof sheathing Temper–

ature 

(°C) Inside Outside Top Bottom Rafter 

–40 — — — — — 

–35 5 2 8 7 6 

–30 9 11 11 8 9 

–25 29 40 38 31 27 

–20 100 123 99 101 103 

–15 248 229 326 268 243 

–10 522 542 536 565 543 

–5 975 1,154 1,009 955 949 

0 1,255 1,440 1,199 1,221 1,255 

5 1,091 1,090 1,047 1,077 1,088 

10 1,015 1,127 929 988 1,012 

15 1,067 1,220 976 1,005 1,028 

20 915 1,093 695 845 895 

25 598 507 416 529 586 

30 430 172 337 374 431 

35 318 10 265 320 349 

40 145 — 218 269 171 

45 34 — 212 135 58 

50 4 — 182 53 7 

55 — — 140 9 — 

60 — — 73 — — 

65 — — 36 — — 

70 — — 8 — — 

75 — — — — — 

Table 20—Exceedance temperatures in WI dry, 

white-shingled structure, 1992 

Time (h) at given temperature at various locations 

Structure Roof sheathing Temper–

ature 

(°C) Inside Outside Top Bottom Rafter 

–40 — — — — — 

–35 — — — — — 

–30 — — 12 2 — 

–25 31 25 36 34 35 

–20 54 66 64 59 53 

–15 168 184 249 200 175 

–10 504 538 574 538 524 

–5 1,271 1,437 1,284 1,281 1,283 

0 1,622 1,713 1,532 1,585 1,603 

5 1,035 976 1,059 1,047 1038 

10 1,037 1,149 1,019 1,057 1,059 

15 1,124 1,407 976 1,058 1,110 

20 793 937 615 742 772 

25 505 316 382 444 477 

30 409 36 303 379 412 

35 199 — 267 256 206 

40 32 — 210 89 37 

45 — — 135 13 — 

50 — — 59 — — 

55 — — 8 — — 

60 — — — — — 

65 — — — — — 

70 — — — — — 

75 — — — — — 
21 

Table 21—Exceedance temperatures in WI dry, 

white-shingled structure, 1993 

Time (h) at given temperature at various locations 

Structure Roof sheathing Temper–

ature 

(°C) Inside Outside Top Bottom Rafter 

–40 — — — — — 

–35 — — — — — 

–30 — — 4 — — 

–25 33 19 69 47 39 

–20 142 147 187 160 146 

–15 278 378 288 281 280 

–10 616 703 662 659 627 

–5 1,054 1,179 1,114 1,074 1,063 

0 1,558 1,567 1,460 1,534 1,544 

5 878 882 839 860 877 

10 1,023 1,119 1,029 1,034 1,039 

15 1,116 1,274 1,030 1,066 1,110 

20 919 1,066 714 848 892 

25 528 389 414 497 526 

30 411 37 335 387 403 

35 161 — 274 226 171 

40 41 — 199 70 40 

45 2 — 95 16 3 

50 — — 31 1 — 

55 — — 13 — — 

60 — — 3 — — 

65 — — — — — 

70 — — — — — 

75 — — — — — 

Table 22—Exceedance temperatures in WI dry, 

white-shingled structure, 1994 

Time (h) at given temperature at various locations 

Structure Roof sheathing Temper–

ature 

(°C) Inside Outside Top Bottom Rafter 

–40 — — 5 4 2 

–35 27 22 36 30 29 

–30 54 64 66 57 53 

–25 96 122 115 111 104 

–20 179 209 182 175 179 

–15 263 299 316 276 266 

–10 578 628 641 620 598 

–5 870 902 907 901 874 

0 1,021 1,095 1,026 1,021 1,039 

5 1,095 1,178 1,037 1,059 1,067 

10 1,075 1,147 1,066 1,087 1,077 

15 1,273 1,501 1,129 1,223 1,251 

20 859 1,024 683 790 844 

25 595 496 439 527 584 

30 446 70 328 421 449 

35 272 3 289 293 277 

40 53 — 246 141 61 

45 4 — 165 22 6 

50 — — 70 2 — 

55 — — 12 — — 

60 — — 2 — — 

65 — — — — — 

70 — — — — — 

75 — — — — — 

Table 23—Exceedance temperatures in WI dry, 

white-shingled structure, 1995 

Time (h) at given temperature at various locations 

Structure Roof sheathing Temper–

ature 

(°C) Inside Outside Top Bottom Rafter 

–40 — — — — — 

–35 — — — — — 

–30 2 — 8 5 3 

–25 55 45 102 66 56 

–20 199 196 257 224 207 

–15 335 397 336 350 336 

–10 607 793 658 620 622 

–5 1,096 1,201 1,085 1,098 1,094 

0 1,217 1,177 1,178 1,206 1,232 

5 1,034 985 990 1,036 1028 

10 919 1,006 887 893 894 

15 849 997 865 855 853 

20 957 1,103 760 899 955 

25 593 642 464 522 569 

30 424 208 307 392 420 

35 301 10 278 279 289 

40 151 — 233 230 172 

45 21 — 164 81 30 

50 — — 130 4 — 

55 — — 47 — — 

60 — — 11 — — 

65 — — — — — 

70 — — — — — 

75 — — — — — 

Table 24—Exceedance temperatures in WI dry, 

white-shingled structure, 1996 

Time (h) at given temperature at various locations 

Structure Roof sheathing Temper–

ature 

(°C) Inside Outside Top Bottom Rafter 

–40 2 — 9 4 3 

–35 24 22 27 25 23 

–30 25 42 31 31 31 

–25 87 85 132 92 86 

–20 229 278 264 258 237 

–15 331 412 348 330 334 

–10 693 682 766 721 706 

–5 1,162 1,271 1,129 1,168 1,167 

0 1,133 1,126 1,063 1,105 1,135 

5 846 921 886 849 832 

10 1,157 1,239 1,204 1,199 1,152 

15 1,127 1,192 917 1,045 1,121 

20 775 996 640 736 759 

25 460 472 359 412 456 

30 420 46 302 370 433 

35 264 — 240 280 255 

40 49 — 223 148 54 

45 — — 147 11 — 

50 — — 79 — — 

55 — — 18 — — 

60 — — — — — 

65 — — — — — 

70 — — — — — 

75 — — — — — 
22 

Table 25—Exceedance temperatures in WI dry, 

white-shingled structure, 1997 

Time (h) at given temperature at various locations 

Structure Roof sheathing Temper–

ature 

(°C) Inside Outside Top Bottom Rafter 

–40 — — — — — 

–35 — — — — — 

–30 4 1 10 6 5 

–25 42 51 57 48 43 

–20 138 165 184 156 146 

–15 234 255 266 253 237 

–10 533 616 603 551 537 

–5 1,219 1,409 1,255 1,253 1,244 

0 1,412 1,429 1,339 1,393 1,409 

5 942 827 936 931 923 

10 1,008 1,139 1,012 1,018 1,005 

15 1,072 1,324 964 1,015 1,048 

20 927 1,042 707 841 913 

25 524 433 404 482 533 

30 405 69 305 389 404 

35 246 — 259 269 251 

40 48 — 200 134 54 

45 6 — 160 17 8 

50 — — 79 4 — 

55 — — 15 — — 

60 — — 5 — — 

65 — — — — — 

70 — — — — — 

75 — — — — — 

Table 26—Exceedance temperatures in WI dry, 

white-shingled structure, 1998 

Time (h) at given temperature at various locations 

Structure Roof sheathing Temper–

ature 

(°C) Inside Outside Top Bottom Rafter 

–40 — — — — — 

–35 — — — — — 

–30 — — 3 — — 

–25 15 13 27 16 14 

–20 63 74 112 79 74 

–15 145 202 160 161 154 

–10 336 357 445 385 370 

–5 930 1,126 1,033 978 947 

0 1,331 1,376 1,272 1,304 1,329 

5 1,045 1,063 1,008 1,046 1,050 

10 1,203 1,295 1,190 1,205 1,210 

15 1,180 1,314 1,120 1,155 1,129 

20 998 1,209 748 895 959 

25 578 640 380 511 585 

30 465 91 337 424 451 

35 387 — 296 362 386 

40 83 — 269 211 99 

45 1 — 220 28 3 

50 — — 107 — — 

55 — — 28 — — 

60 — — 5 — — 

65 — — — — — 

70 — — — — — 

75 — — — — — 

Table 27—Exceedance temperatures in WI dry, 

white-shingled structure, 1999 

Time (h) at given temperature at various locations 

Structure Roof sheathing Temper–

ature 

(°C) Inside Outside Top Bottom Rafter 

–40 — — — — — 

–35 3 2 8 5 4 

–30 8 12 10 9 8 

–25 20 37 50 23 22 

–20 140 150 168 162 156 

–15 311 339 408 336 312 

–10 604 598 565 607 604 

–5 990 1,176 1,080 1,021 1,008 

0 1,171 1,184 1,111 1,152 1,168 

5 1,065 1,137 1,050 1,048 1,079 

10 1,043 1,067 950 1,006 1,019 

15 1,072 1,218 1,023 1,069 1,068 

20 874 1,111 731 815 846 

25 584 547 420 528 575 

30 443 174 323 413 440 

35 295 8 266 333 296 

40 126 — 239 163 140 

45 11 — 199 62 15 

50 — — 106 8 — 

55 — — 42 — — 

60 — — 11 — — 

65 — — — — — 

70 — — — — — 

75 — — — — — 

Appendix B—Exceedance 

Temperature Data for MS 

Structures 

The data in the following tables (Tables 28 to 35) show 

exceedance temperature data for field exposure structures in 

Starkville, Mississippi, from 1996 to 1999. 
23 

Table 28—Exceedance temperatures in MS dry, 

black-shingled structure, 1996 

Time (h) at given temperature at various locations 

Structure Roof sheathing Temper–

ature 

(°C) Inside Outside Top Bottom Rafter 

–40 — — — — — 

–35 — — — — — 

–30 — — — — — 

–25 — — — — — 

–20 5 3 17 12 7 

–15 22 39 58 20 23 

–10 99 153 148 118 100 

–5 234 351 335 295 254 

0 576 596 593 564 560 

5 818 996 780 797 805 

10 1,056 1,183 1,043 1,034 1,035 

15 1,155 1,382 1,206 1,118 1,147 

20 1,717 2,085 1,456 1,657 1,700 

25 1,008 1,119 638 828 980 

30 610 710 438 574 598 

35 483 167 327 422 476 

40 488 — 363 406 456 

45 415 — 317 401 428 

50 98 — 257 348 212 

55 — — 315 188 3 

60 — — 243 2 — 

65 — — 202 — — 

70 — — 48 — — 

75 — — — — — 

Table 29—Exceedance temperatures in MS dry, 

black-shingled structure, 1997 

Time (h) at given temperature at various locations 

Structure Roof sheathing Temper–

ature 

(°C) Inside Outside Top Bottom Rafter 

–40 — — — — — 

–35 — — — — — 

–30 — — — — — 

–25 — — — — — 

–20 — — 1 — — 

–15 13 5 33 19 14 

–10 61 61 109 79 63 

–5 182 214 314 228 196 

0 640 733 728 668 625 

5 983 1,147 929 952 970 

10 1,095 1,327 1,081 1,069 1,096 

15 1,223 1,543 1,144 1,170 1,200 

20 1,500 1,854 1,348 1,439 1,466 

25 1045 1,121 603 817 999 

30 611 674 399 542 626 

35 492 81 338 515 493 

40 482 — 334 383 457 

45 342 — 356 405 387 

50 91 — 275 314 167 

55 — — 287 157 1 

60 — — 260 3 — 

65 — — 184 — — 

70 — — 37 — — 

75 — — — — — 

Table 30—Exceedance temperatures in MS dry, 

black-shingled structure, 1998 

Time (h) at given temperature at various locations 

Structure Roof sheathing Temper–

ature 

(°C) Inside Outside Top Bottom Rafter 

–40 — — — — — 

–35 — — — — — 

–30 — — — — — 

–25 — — — — — 

–20 — — — — — 

–15 — — 2 — — 

–10 20 7 86 34 22 

–5 206 228 324 266 217 

0 539 554 653 561 535 

5 947 1,179 877 917 939 

10 1,013 1,210 958 991 996 

15 1,026 1,258 1,070 981 1,008 

20 1,554 1,815 1,457 1,543 1,526 

25 1,146 1,299 670 907 1,092 

30 652 962 394 582 674 

35 479 248 371 499 500 

40 530 — 323 394 466 

45 465 — 363 432 506 

50 181 — 292 405 268 

55 2 — 327 230 11 

60 — — 315 18 — 

65 — — 191 — — 

70 — — 85 — — 

75 — — 2 — — 

Table 31—Exceedance temperatures in MS dry, 

black-shingled structure, 1999 

Time (h) at given temperature at various locations 

Structure Roof sheathing Temper–

ature 

(°C) Inside Outside Top Bottom Rafter 

–40 — — — — — 

–35 — — — — — 

–30 — — — — — 

–25 — — — — — 

–20 — — 12 4 — 

–15 17 11 21 20 16 

–10 40 39 83 55 43 

–5 185 177 352 242 191 

0 453 482 463 453 454 

5 778 999 840 796 765 

10 1,147 1,373 1,088 1,097 1,101 

15 1,194 1,510 1,215 1,161 1,199 

20 1,611 1,944 1,332 1,487 1,558 

25 1,079 1,234 651 911 1,074 

30 684 784 453 624 688 

35 522 207 383 493 503 

40 527 — 372 413 485 

45 370 — 317 432 457 

50 148 — 311 358 196 

55 5 — 309 186 30 

60 — — 270 28 — 

65 — — 198 — — 

70 — — 84 — — 

75 — — 6 — — 
24 

Table 32—Exceedance temperatures in MS wet, 

black-shingled structure, 1996 

Time (h) at given temperature at various locations 

Structure Roof sheathing Temper–

ature 

(°C) Inside Outside Top Bottom Rafter 

–40 — — — — — 

–35 — — — — — 

–30 — — — — — 

–25 — — — — — 

–20 — 3 12 3 — 

–15 20 39 18 21 22 

–10 40 153 157 73 47 

–5 286 351 358 306 290 

0 647 596 596 620 613 

5 860 996 810 810 811 

10 1,122 1,183 1,012 1,031 1,072 

15 1,180 1,382 1,176 1,120 1,150 

20 1,780 2,085 1,493 1,684 1,740 

25 923 1,119 681 901 996 

30 568 710 479 618 609 

35 542 167 331 435 507 

40 453 — 363 452 470 

45 350 — 303 404 387 

50 13 — 304 290 70 

55 — — 286 16 — 

60 — — 250 — — 

65 — — 146 — — 

70 — — 9 — — 

75 — — — — — 

Table 33—Exceedance temperatures in MS wet 

black-shingled structure, 1997 

Time (h) at given temperature at various locations 

Structure Roof sheathing Temper–

ature 

(°C) Inside Outside Top Bottom Rafter 

–40 — — — — — 

–35 — — — — — 

–30 — — — — — 

–25 — — — — — 

–20 — — — — — 

–15 3 5 22 11 3 

–10 29 61 106 43 33 

–5 211 214 289 234 207 

0 671 733 705 652 637 

5 994 1,147 936 956 988 

10 1,157 1,327 1,078 1,083 1,114 

15 1,258 1,543 1,169 1,199 1,210 

20 1,540 1,854 1,369 1,478 1,547 

25 1,025 1,121 644 914 1,048 

30 612 674 418 611 622 

35 524 81 375 476 484 

40 441 — 359 449 471 

45 275 — 328 388 316 

50 20 — 273 244 80 

55 — — 309 22 — 

60 — — 248 — — 

65 — — 127 — — 

70 — — 5 — — 

75 — — — — — 

Table 34—Exceedance temperatures in MS wet, 

black-shingled structure, 1998 

Time (h) at given temperature at various locations 

Structure Roof sheathing Temper–

ature 

(°C) Inside Outside Top Bottom Rafter 

–40 — — — — — 

–35 — — — — — 

–30 — — — — — 

–25 — — — — — 

–20 — — — — — 

–15 — — — — — 

–10 — 7 57 3 — 

–5 221 228 313 248 212 

0 543 554 624 551 519 

5 973 1,179 906 917 939 

10 1,070 1,210 942 1,014 1,038 

15 1,064 1,258 1,061 983 1,063 

20 1,697 1,815 1,484 1,588 1,580 

25 1,085 1,299 722 1,009 1,150 

30 644 962 437 673 680 

35 550 248 392 471 537 

40 546 — 371 482 549 

45 346 — 316 494 388 

50 21 — 330 297 105 

55 — — 350 30 — 

60 — — 258 — — 

65 — — 171 — — 

70 — — 26 — — 

75 — — — — — 

Table 35—Exceedance temperatures in MS wet, 

black-shingled structure, 1999 

Time (h) at given temperature at various locations 

Structure Roof sheathing Temper–

ature 

(°C) Inside Outside Top Bottom Rafter 

–40 — — — — — 

–35 — — — — — 

–30 — — — — — 

–25 — — — — — 

–20 — — 7 — — 

–15 8 11 17 13 10 

–10 21 39 66 25 23 

–5 196 177 305 227 218 

0 452 482 477 450 466 

5 831 999 832 786 811 

10 1,169 1,373 1,095 1,102 1,091 

15 1,349 1,510 1,232 1,219 1,252 

20 1,728 1,944 1,355 1,573 1,661 

25 1,077 1,234 698 1,021 1,100 

30 677 784 490 683 697 

35 610 207 415 511 569 

40 479 — 369 502 540 

45 162 — 349 434 265 

50 1 — 341 193 57 

55 — — 301 21 — 

60 — — 245 — — 

65 — — 135 — — 

70 — — 31 — — 

75 — — — — —