Building Performance Assessment:
Hurricane Fran in North Carolina
Observations, Recommendations, and Technical Guidance
Federal Emergency Management Agency
Mitigation Directorate
Washington, DC and Region IV, Atlanta, Georgia
FEMA 290/March 1997
3 RECOMMENDATIONS
3.1 Building Foundation Systems
3.1.1 Piling Embedment for Structural Support
It is critical that coastal foundations be designed to survive the anticipated 
amount of erosion and scour. Erosion and scour combine to impact coastal piling 
foundations in three distinct ways. First, in the absence of cross-bracing, the 
loss of soil adjacent to a thin vertical foundation member results in a longer 
unsupported length. The increase in unsupported length allows for greater 
deflection of the vertical member. Second, the loss of soil adjacent to pilings 
leaves less soil to counteract lateral loads applied to the pilings by the 
structure above, the velocity flow of the storm surge, wave action, and debris 
impact. Third, pilings, which rely on friction between the piling and the 
adjacent soil to transfer loads into the ground, lose some of the resisting 
friction when the adjacent soil is eroded and scoured. The loss of friction 
reduces the ability of the piling to resist uplift loads from wind.
For the concerns discussed above to be adequately addressed, designs of coastal 
foundation systems must account for the conditions expected to occur during the 
base flood (100-year flood) and long-term erosion for the life of the building. 
The following documents offer guidance to designers of coastal foundations:
- The ASCE standard ASCE 7-95, Minimum Design Loads Building and Other 
Structures. The 1995 version of this standard includes, for the first time, 
criteria for determining flood loads (Chapter 5) and for combining flood and 
other loads to determine combined load factors (Chapter 2) for buildings that 
experience simultaneous wind and flood loads. This standard is available from 
ASCE. Portions, if not the whole standard, may well be incorporated by the model 
building code organizations into future versions of model building codes. This 
standard also meets, or exceeds, the minimum requirements of the NFIP for 
determining loads.
- The ASCE standard Flood Resistant Design and Construction Practices. This 
standard is currently in development and should be completed in 1997. It will be 
available from ASCE. This new standard will provide descriptive as well as 
prescriptive requirements regarding the design and construction of buildings 
that are to be located in floodprone areas. The draft of this standard presents 
the recommendations of some of the Nations leading experts in coastal 
construction and meets or exceeds the minimum requirements of the NFIP.
- FEMAs Coastal Construction Manual (FEMA 55). This document provides further 
guidance on coastal foundation systems. It recommends that pilings be embedded 
to a depth of -10 feet m.s.l. 
- FEMAs Technical Bulletin No. 5, Free of Obstruction Requirements for 
Buildings Located in Coastal High Hazard Areas. This document provides 
information on NFIP-compliant design and construction practices that can prevent 
damage to coastal buildings caused by below-building obstructions.
The BPAT recommends that in the absence of State or local requirements based on 
detailed engineering studies or the historical performance of coastal buildings 
subjected to base flood conditions, pilings for structures in areas subject to 
erosion and scour be embedded to -10 feet m.s.l. In areas with terminating 
strata that inhibit erosion and scour, and areas with rocky shorelines, 
foundation systems with shallower depths may be justified.
The findings of the W-C study suggest that in coastal areas of North Carolina 
where the ground elevations are at or below 11 feet m.s.l. the current 
requirements of the State Building Code regarding piling embedment depth may 
have been adequate to prevent foundation failure during Hurricane Fran. However, 
given the limitations of that study (as discussed in Appendix C), and the 
anticipated revisions to BFEs for North Carolina coastal communities as 
discussed in Section 2.10 of this report, it may be appropriate for the state to 
consider the need for piling embedment depth requirements more stringent than 
those in its current Code. These issues are discussed below.
All of the structures tested by W-C were located where the ground elevation was 
11 feet m.s.l. or less. To meet the applicable code requirement, the pilings for 
these structures had to be embedded to a minimum of -5 feet m.s.l. In areas 
where the grade is greater than 11 feet m.s.l., pilings will meet the State Code 
if they are embedded 16 feet below average original grade. As a result, the 
bottoms of the pilings in these areas will be above -5 feet m.s.l. This 
embedment depth may not be sufficient for structures built on or directly behind 
frontal dunes, where extensive erosion and scour can cause the loss of the 
entire dune or remove so much of it that piling support becomes inadequate. 
There are areas within the state where this situation can occur. For structures 
in these areas, the state may want to consider revising the Code to require that 
piling embedment depth be -5 feet m.s.l. or 16 feet below grade, whichever is 
greater.
As noted in Section 2.10, FEMA is preparing revised FIRMs for several North 
Carolina communities affected by Hurricane Fran. Because the revised FIRMs are 
expected to include BFEs higher than those shown on the current FIRMs, new 
structures and substantially damaged structures that are reconstructed will have 
to be elevated higher to meet minimum NFIP requirements. As a result, these 
structures may be subject to different wind and flood loads than structures 
built previously, when lower elevation requirements applied, and increased 
piling embedment may be necessary.
In addition, the findings of the W-C study suggest that the State of North 
Carolina needs to emphasize the importance of inspection and code enforcement to 
ensure that all structure pilings meet current and any future Code requirements.
3.1.2 Piling Foundations for Decks, Porches, and Roof Overhangs
The design criteria for vertical foundation members for building extensions such 
as porches, decks, and roof overhangs must be equal to those for the foundation 
system of the main structure. 
Oceanfront Residential Buildings
The vertical foundation members for decks, porches, and roof overhangs must be 
designed and constructed to maintain their ability to support the structure 
above. These building extensions are often on the ocean side of oceanfront 
structures, where they are exposed to amounts of storm surge, velocity flow, 
wave action, vertical erosion, and localized scour at least as great as those 
that affect the main structure. The foundation requirements for these building 
extensions should never be less stringent than those for the building itself. 
Because of the damage caused to the main structure when building extensions 
collapse and the debris they generate once they collapse, they should not be 
considered sacrificial. The only exceptions would be stairways and narrow 
walkways required for building access.
In areas subject to erosion and scour, embedment of vertical foundation members 
for building extensions should be based on a depth related m.s.l., not a depth 
below existing grade. The BPAT recommends that in these areas, the requirements 
applied to the main building support system also be applied to the piling 
foundations for decks, porches, and roof overhangs. This recommendation is based 
on the observed performance of coastal buildings in many hurricanes, including 
Hurricane Fran. 
Landward Residential Buildings
In landward areas also, vertical foundation supports for building extensions 
such as decks, porches, and roof overhangs should meet the same requirements 
applied to the main building support system. In areas not subject to erosion but 
subject to localized scour, embedment of these foundation members may be based 
on a depth related to existing grade. From the observed performance of landward 
coastal buildings and building extensions, the continued use of an embedment 
depth of 8 feet is recommended for all vertical foundation members.
3.1.3 Grade of Lumber Used for Timber Pilings and Cross-Bracing
The requirements of the North Carolina State Building Code regarding the quality 
of wood materials used in the construction of residential building foundations, 
including wood piles and dimensional lumber, are set forth in Section R-309 of 
the Code. Section R-309 specifically addresses protection against decay. It 
states that all pressure-treated wood foundation members must bear the quality 
mark of a quality control inspection agency for pressure-treated wood that has 
been approved by the State Building Code Council. It does not contain any 
explicit requirements regarding grades of lumber used for vertical foundation 
members or cross bracing. Contractors and inspectors must therefore depend on 
their judgment in determining acceptable grades of lumber for these 
applications. To help avoid situations in which foundation strength is 
compromised by the use of lower-quality wood materials (as depicted in Figure 2-
20), the State should consider amending the Code to include prescriptive 
language regarding the grade of wood materials used for vertical members and 
cross bracing in structure foundations.
3.1.4 Proper Elevation of Coastal Buildings
Buildings constructed in Coastal High Hazard Areas (V zones  as shown on NFIP 
FIRMs) must be elevated so that the lowest horizontal structural member of the 
lowest floor is at or above the BFE and the area below the building is free of 
obstructions. These requirements are intended to allow velocity flows and waves 
to pass freely under the building. When a building in a V zone meets these 
requirements, its lowest floor is usually 12 inches or more above BFE, because 
of the thickness of the floor diaphragm and the supporting beams. FIRMs for 
coastal communities usually show A zones landward of V zones. In A zones, a 
buildings lowest floor must be elevated to or above the BFE, and areas below 
the BFE may contain obstructions. In B, C, and X zones, no elevation 
requirements apply.
The practice of elevating buildings on open foundations and ensuring that the 
lowest horizontal structure member is above the BFE was widely used in A, B, C, 
and X zones on the barrier islands impacted by Hurricane Fran. Homes in these 
zones were often elevated 8 to 9 feet on embedded piling foundations to allow 
below-building parking and storage. This practice undoubtedly resulted in much 
lower damages than would have occurred if the lowest floors of these homes had 
been elevated to the BFE in A zones and not elevated in  B, C, and X zones. The 
practice of requiring V zone construction standards in coastal A zones exceeds 
NFIP minimum requirements. Coastal A zones subjected to velocity flow and wave 
action are not distinguished from other A zones on FIRMs. Communities on barrier 
islands may want to consider adopting stricter standards in areas of known high 
coastal hazard, whether or not they are currently identified as V zones.
A building elevated so that its lowest floor is above BFE can qualify for an 
extremely favorable flood insurance rate. Rates for buildings in both Zone A and 
Zone V are lowered incrementally for each 1-foot increase in the height of the 
lowest floor above the BFE, up to a maximum of 4 feet. For buildings at this 
height, the rate reduction is 33 percent in Zone A and 60 percent in Zone V. 
Rate reductions are justified because a building that exceeds the minimum 
elevation requirements generally has a low risk of being significantly damaged 
by flooding. Therefore, in the design process for a new building, elevating 
above the BFE is well worth considering. Local insurance agents can provide 
information concerning the flood insurance rates associated with elevating above 
the BFE.
3.1.5 Cross-Bracing Below Elevated Buildings
Whenever possible, piling foundations should be designed to withstand 
simultaneous wind and flood loads without the use of cross-bracing. Alternatives 
to cross-bracing that may provide the necessary stability include incorporating 
a structural, unroofed deck into the building design to increase the building 
footprint; using pilings that are larger, longer, or both; and reducing piling 
spacing. When cross-bracing is necessary, its use should be minimized to the 
extent possible, especially where it would be perpendicular to velocity flow, 
wave action, and debris impact. Whenever cross-bracing is used, regardless of 
its orientation, it must be designed to withstand the anticipated wind and flood 
loads.
3.1.6 Solid Perimeter Masonry Foundation Walls Supported on a Continuous Footing
The use of solid perimeter foundation walls in coastal flood hazard areas should 
be scrutinized carefully. Since these foundations create large obstructions to 
velocity flow and are usually backfilled with the native sandy material, they 
are extremely susceptible to extensive localized scour. This condition was 
observed to have occurred even in overwash areas where accretion of sand 
occurred.  Scour occurred where the velocity flow was disrupted at the seaward 
face of the obstruction and where the flow reconverged at the landward face of 
the obstruction. 
Only where an engineering analysis of potential scour has been completed by a 
professional engineer should coastal communities consider allowing solid 
perimeter wall foundation systems in landward areas subject to high-velocity 
flow. Engineering solutions to this problem could include backfilling the 
foundation excavation with soil that is resistant to scour and installing the 
footing at a depth that is below the expected depth of scour (see Figure 3-1). 
The preferred solution is to construct piling foundations in landward areas 
subject to high-velocity flow. Of course, solid perimeter walls should never be 
used in oceanfront areas and are not permitted in V Zones.
[Begin figure]
Figure 3-1 is an illustration showing deepening foundation to account for scour.
[End figure]
3.1.7 Manufactured (Mobile) Home and Permanently Installed RV Foundations
Manufactured (mobile) homes and permanently installed RVs are usually supported 
on dry-stack masonry foundations. When manufactured homes and RVs are installed, 
steps should be taken to protect them from the damage caused by foundation 
collapse due to scour, anchor strap failure due to corrosion, and anchor strap 
pullout due to the use of the wrong size or type of anchor.
Protecting the foundation from localized scour requires either controlling scour 
or providing a foundation that extends to a depth that is below the expected 
depth of scour. For example, controlling scour may involve excavating the area 
under the footprint of the home and replacing the excavated soil with a non-
scourable soil or installing a geotextile fabric beneath the home. If a fabric 
is installed, it must be keyed-in around the edges so that the scour will not 
undercut the fabric. Providing a deep foundation can be done at minimal expense. 
A power-driven auger can be used to drill holes to a depth that exceeds the 
depth of the scour. The augured holes should be at least 1 foot in diameter and 
should exceed the expected scour depth by at least 1 foot. The deep foundation 
can consist of a wood post or cast-in-place concrete footing.
Metal straps used to tie down manufactured homes and RVs can become loose over 
time. In coastal areas, metal straps are also subject to higher rates of 
corrosion. Loose or corroded straps exposed to the loads imposed by high winds 
and flood waters are prone to failure, which can lead to damage to the 
foundation and home. It is critical that straps be checked periodically for both 
proper tension and corrosion. Checks for tension should be made frequently 
throughout the hurricane season and are especially important after high-wind 
events. All loose straps should be tightened according to the manufacturers 
specifications. Straps that show visible signs of corrosion should be replaced. 
In coastal areas, metal straps have been shown to exhibit signs of corrosion 
after 3 to 5 years of exposure.
Pullout of anchors to soil saturation can be minimized through the use of the 
proper size and type of anchor. Anchors used in sandy soils prone to saturation 
by flood waters must either be long enough that the helical plates extend to a 
depth below the saturated soil, into soil that can resist anchor pullout, or be 
designed to work properly in saturated soil. In coastal areas subject to high-
velocity flow that have loose to medium-dense sands and other granular soils, 
anchors should be  at least 4 feet long and 3/4 inch in diameter and should have 
helical plates at least 6 inches in diameter. Major anchor manufacturers provide 
guidelines for selecting and installing the appropriate anchor according to the 
size of the home, the soil type at the installation site, and other conditions 
that can affect anchor performance. The manufacturers specifications and 
recommendations should always be followed in the selection and installation of 
anchors.
To minimize the impact of tidal surge on manufactured homes and their 
foundations, it is recommended that in all Special Flood Hazard Areas subject to 
coastal flooding, including A zones, manufactured homes be elevated such that 
the bottom of the lowest horizontal structural member of the lowest floor is at 
or above the BFE. This means that the bottoms of the chassis I-beams would be at 
or above the BFE.
3.2 Breakaway Walls Below Elevated Buildings
When an area below an elevated building is enclosed with breakaway wall panels, 
special care should be taken to ensure that the placement and attachment of the 
panels does not interfere with the ability of the panels to break away when 
acted on by flood forces. 
3.2.1 Placement of Exterior Sheathing Over Pilings
Exterior sheathing attached to breakaway wall panels must not extend over the 
vertical foundation members. This also applies to wire mesh used in exterior 
stucco systems. There should be a free and clear joint between the panels and 
vertical foundation members so that unnecessary lateral loads are not 
transferred to the foundation (see Figures 3-2 and 3-3). FEMAs Coastal 
Construction Manual provides guidance on how to fabricate wood-frame, metal-
frame, and masonry breakaway panels. 
[Begin figures]
Figure 3-2 is an illustration showing recommended practice for breakaway wall 
sheathing.
Figure 3-3 is an illustration showing recommended breakaway wall attachment.
[End figures]
3.2.2 Improper Attachment of Breakaway Wall Panels to Foundation Members
The attachment of breakaway wall panels to surrounding surfaces should be done 
in such a way that the panels will safely resist wind loads but break away under 
coastal flood loads (see Figure 3-3). Local building codes provide information 
on applicable wind loads that building components must resist. FEMAs Coastal 
Construction Manual provides guidance on how to properly attach breakaway wall 
panels.
3.2.3 Placement of Breakaway Wall Panels Seaward of Cross-Bracing
As a matter of practice, breakaway walls should never be installed immediately 
seaward of cross-bracing. This practice exposes the cross-bracing to lateral 
loads that far exceed those that 2x bracing is able to resist. In most 
instances, an alternative is to install latticework or move cross-bracing away 
from breakaway wall panels, into an interior area.
3.3 Below-Building Concrete Slabs
When a slab-on-grade is constructed below an elevated building, it should be 
designed and constructed in such a way that it will not damage the building 
foundation when acted on by flood forces. Issues requiring special consideration 
include the thickness of the slab, slab joints, and construction practices that 
are not appropriate for coastal flood hazard areas subject to erosion and scour.
3.3.1 Slab Thickness 
Slabs below elevated buildings in areas subject to erosion and scour should be 
no thicker then 4 inches. Thicker slabs present two problems: they are harder to 
break into small pieces and each piece weighs more per unit of surface area than 
a same-sized piece of a thinner slab.
3.3.2 Slab Joints 
Of the three types of joints described in Section 2.5.2, contraction joints are 
the most important for ensuring the frangibility of below-building slabs. As 
shown in Figure 3-4, contraction joints should be cut into the surface of the 
slab from piling to piling in both directions across the entire slab. Expansion 
and isolation joints should be installed as appropriate in accordance with 
standard practice or as required by State and local codes.
[Begin figure]
Figure 3-4 is an illustration of recommended contraction joint layout for 
frangible slab-on-grade below elevated building.
[End figure]
3.3.3 Wire Mesh 
Wire mesh retards the ability of the slab to break apart and therefore should 
not be used.
3.3.4 Connecting the Slab to the Vertical Foundation Members
Slabs should never be connected to vertical foundations members when the slab is 
underlain by granular soil in areas subject to erosion and scour. This practice 
unnecessarily threatens the stability of the foundation system of elevated 
buildings.
3.3.5 Casting Concrete Grade Beams and Slabs-On-Grade Monolithically 
Grade beams and slabs-on-grade should never be cast monolithically in areas 
subject to erosion and scour. In these areas, grade beams must be designed to be 
self-supporting (to account for the loss of supporting soil from erosion and 
scour) and to withstand velocity flow and debris impact as well as stiffen the 
foundation system.  All slabs-on-grade must designed to act separately from 
grade beams.
3.3.6 Concrete Collars
In areas subject to erosion and scour, concrete collars should not be placed 
around foundation pilings.
3.4 On-Site Utility Systems
On-site utilities need to be installed with much greater attention to the 
effects of flooding. In some cases, such as placement of electrical meters, 
installation will need to be coordinated with local public utility companies. 
Installation of other items, such as septic systems, may fall under the purview 
of local or State health departments.
3.4.1 Air Conditioner / Heat Pump Compressor Platforms
Platforms that support air conditioner / heat pump compressors must be designed 
to withstand the forces associated with the base flood. In a coastal floodplain, 
the best way to avoid damage to these platforms is to employ the method used for 
the protection of buildings  elevation. Therefore the bottom of the lowest 
horizontal structural member of the platform should be elevated to or above the 
BFE. Ideally, platforms should be cantilevered from an elevated floor diaphragm 
(see Figure 3-5). An alternative is to support the platform partially or 
completely on pilings (see Figure 3-6).
[Begin figures]
Figure 3-5 is an illustration of a cantilevered mechanical platform
Figure 3-6 is an illustration of a mechanical platform supported by pilings.
[End figures]
Platforms designed and constructed with vertical foundation members must be 
protected from localized scour and, in oceanfront areas, protected from erosion 
so that the foundation members can resist the velocity flow, wave action, and 
debris impact found in coastal areas. When a vertical foundation member looses 
it ability to support the platform, the platform collapses, becoming waterborne 
debris that is then carried into the structure or nearby structure. Because of 
the cost of the compressor (often $2,000 and up), the potential loss of 
habitability when the compressor is rendered inoperable, and the debris that 
platforms generate once they collapse, these platforms cannot be considered 
sacrificial. 
Vertical foundation members for compressor platforms in landward areas should 
meet the same requirements as the main building support system. In areas subject 
to scour, embedment of these foundation members should be based on a depth 
related to existing grade. From the observed performance of oceanfront 
buildings, an embedment depth of -10 feet m.s.l. is recommended for all vertical 
foundation members for oceanfront buildings.  From the observed performance of 
landward coastal buildings, an embedment depth of 8 feet below existing grade is 
recommended for platform vertical foundation members. These recommendations are 
considered prudent in the absence of specific State and local requirements.
3.4.2 Placement of Utilities on, Through, or Adjacent to Breakaway Wall Panels
Utility services should never be placed in a such a manner that they can be 
damaged when a breakaway wall panel breaks away or in such a way that they will 
interfere with the function of the breakaway panels. As noted in Section 2.6, 
the BPAT observed numerous types of utility system components mounted on or 
adjacent to breakaway wall panels. This practice is unacceptable and almost 
always results in the utility components being severely damaged during a 
hurricane. The BPAT also observed utility lines penetrating breakaway wall 
panels. This practice is also unacceptable. When it becomes necessary to extend 
these lines through a wall panel, a utility blockout, as shown in Figure 3-3, 
should be built into the wall.
3.4.3 Placement of Utilities Adjacent to Vertical Support Members
Utilities installed on the landward side of vertical foundation members are 
shielded by the foundation members against damage from velocity flow and debris 
impact. Service connections such as electrical meters, telephone junction boxes, 
and cable junction boxes that must be exposed to flooding should be placed on 
the landward side of the most landward vertical foundation member (see Figure 3-
7). Vertical utilities such as sewer and water risers should also be placed on 
the landward side of vertical foundation members.
[Begin figure}
Figure 3-7 is an illustration of the proper location of utilities.
[End figure]
3.4.4 Septic Tanks
Septic tanks should be installed as far landward as practical and permitted by 
the authority having jurisdiction. Before septic tanks are installed, local and 
State Health Departments having regulatory control should be consulted 
concerning whether such tanks are permissible and how and where they should be 
installed.
3.5 Dry Floodproofing
The NFIP regulations do not permit the use of dry floodproofing in Coastal High 
Hazard Areas (V zones), which are subject to deep flooding, high-velocity flow, 
debris impact, and wave heights. The regulations do allow nonresidential 
buildings in A zones, including coastal A zones, to be dry floodproofed through 
the construction of walls that are substantially impervious to the passage of 
flood waters. Dry floodproofing in coastal A zones, however, presents special 
challenges. Although the potential for high-velocity flow, debris impact, and 
wave action in coastal A zones is significantly less than in V zones, it still 
must be assessed and accounted for in the dry floodproofing design.
Studies performed by the U.S. Army Corps of Engineers (COE) National Flood 
Proofing Committee, found in the COE publication Floodproofing Tests, 1988, 
indicate that dry floodproofing can be used in areas that experience flooding to 
a depth of 3 feet. The COE did not study coastal effects, including wave action. 
Wave action, especially waves breaking on the vertical dry floodproofing 
components, will add significant loads to the floodproofing system. 
Therefore, it is recommended that dry floodproofing be used in coastal 
floodplains only where the stillwater depth is no more than 2 feet above grade 
during the base flood. Where the stillwater depth is 2 feet, the wave crest 
elevation will be approximately 1 foot above the stillwater elevation, and wave 
breaking and overtopping will reach even higher. To protect a building from wave 
overtopping where the stillwater depth is 2 feet, 4 feet of dry floodproofing is 
recommended (see Figure 3-8). In no case should the increase in floodproofing 
height be used to compensate for higher stillwater depths without a detailed 
engineering analysis.
[Begin figure}
Figure 3-8 is an illustration of dry floodproofing in coastal A zones.
[End figure]
Dry floodproofing is normally designed for velocity flows that do not exceed 10 
feet per second. Velocities up to 10 feet per second can be converted to an 
approximate equivalent hydrostatic head (see FEMA 259: Engineering Principles 
and Practices for Retrofitting Flood Prone Residential Buildings). In the case 
of structure subjected to a 2-foot stillwater flood depth, a velocity of 10 feet 
per second can be converted to an approximate increase of 1 foot of flood depth. 
This provides further justification for restricting floodproofing to coastal 
structures that are subject to no more than 2 feet of stillwater flooding. For 
additional information on proper floodproofing design and construction criteria, 
see FEMA 259, Engineering Principles and Practices for Retrofitting Flood-Prone 
Residential Structures, and FEMAs Technical Bulletin No. 3, Non-Residential 
Floodproofing  Requirements and Certification.
3.6 Wind Damage Protection
The observed wind damage to porch roofs and large overhangs can be avoided in 
the future through the use of easily implemented and inexpensive retrofits, such 
as the addition of corrosion-resistant metal connectors at critical locations. 
Revising the State Building Code to include construction details for top-of-
column and bottom-of-column connections would help ensure that future 
construction is better able to resist high winds.
3.7 Protection of Metal Structural Components from Corrosion
Maintaining the design strength of all structural components is critical. Any 
loss of strength can lead to structural failure during subsequent hurricanes. 
FEMA recently issued NFIP Technical Bulletin No. 8, Corrosion Protection for 
Metal Connectors in Coastal Areas, which provides guidance concerning the 
selection, installation, and maintenance of metal connectors such as truss 
plates and hurricane straps.