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READ AND **REMOVE THIS PAGE** BEFORE PLACING

THE SPECIFICATION SECTION IN THE CONTRACT

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[DIVISION 9: FINISHES]{.underline}

SECTION 09221 ‑ STUCCO

USE: Furnishing and installing the materials and stuccoing the exterior
of buildings.

**NOTES TO SPECIFIER:**

A. Options within paragraphs are identified by enclosure in brackets;
blank spaces enclosed by brackets \[\_\_\_\_\_\] provide for information
to be inserted, as appropriate, to individual projects.

B. **TO AVOID CONFLICTING REQUIREMENTS AND COSTLY MISTAKES,** the
specifier must edit (delete, substitute or add to the text). The
remaining paragraphs must be renumbered.

C. DELETE FOR FINAL COPY: Notes to the Specifier, located between lines
of asterisks; all \[brackets\], [underlining]{.underline}, **boldface**,
and *italics*, within the paragraphs; and this page. (Open Reveal Codes
\[alt F3\] to do this accurately.)

D. [To Edit "(Footer B)":]{.underline} (Corel 8). **ENTIRE FOOTER SHOULD
BE BOLDED.** Click in the footer and delete the "Project Name (ftr B)"
text and replace it with the **Name of the Project (upper and lower
case)**. Replace date with current MM/YY (WITHOUT BRACKETS).

E. The Guide Specifications are intended to be continuously reviewed and
revised. User's technical comments are appreciated. Also, other related
or similar specification that are written "from scratch" that could
benefit others, or other questions can be sent to NSTC A/E Group, ST
110, or call (303) 987-6868.

**DRAWING DATA REQUIRED:**

**REQUIRED SPEC MODIFICATIONS:**

[GENERAL NOTES]{.underline}

A. Whenever entire articles, paragraphs, or subparagraphs are not
applicable, the articles, paragraphs, or subparagraphs should be
deleted; when necessary, reletter or renumber articles, paragraphs, or
subparagraphs.

B. THIS GUIDE IS NOT INTENDED AS A SUBSTITUTE FOR READING THE ENTIRE
SECTION.

[TECHNICAL NOTES]{.underline}

A. 1.1B: Select or add applicable specification sections. Do not list
specification sections from Division 9.

B. l.2: Select or add applicable references.

C. l.3A: Select applicable section.

D. l.3B: Insert number of copies of Certificates of Conformance
required. Normally 3 copies are required. Distribution after review is
normally l copy to the CO, l copy to the Contractor, and l copy to the
project file.

E. 1.3C: Insert number of samples required. Normally 2 samples are
required. Distribution after review is normally 1 sample to the COR, and
1 sample to the Contractor.

F. 2.1A: Select type of cement to be used.

G. 2.1B: Select type of cement to be used.

H. 2.1G: Insert color desired.

I. 4.1 and 4.2: When a \"lump sum\" Contract is used, delete the title
PART 4: MEASUREMENT AND PAYMENT, and both articles from this
specification section. Measurement and payment will be addressed in Part
4 of Section 01010.

**REVISIONS OF THIS SECTION:**

CSI format, editorial changes: 12/01

Metric:

Technical Update: 06/92

SECTION 09921

STUCCO

[PART 1: GENERAL]{.underline}

1.1 SUMMARY:

A. Section Includes: Furnishing and installing the materials for
stuccoing the exterior of the structure.

1.2 REFERENCES:

A. American Society for Testing and Materials:

ASTM C 28‑92 Gypsum Plasters

ASTM C 35 REV A-89 Inorganic Aggregates for Use in Gypsum Plaster

ASTM C 59‑91 Gypsum Casting and Molding Plaster

ASTM C 61‑91 Gypsum Keene\'s Cement

ASTM C 91‑E1-91 Masonry Cement

ASTM C 144‑E1-91 Aggregate for Masonry Mortar

ASTM C 150‑92 Portland Cement

ASTM C 206-E1-91 Finishing Hydrated Lime (R 1992)

ASTM C 472 REV A-90 Test Method for Physical Testing of Gypsum, Gypsum
Plasters and Gypsum Concrete

1.3 SUBMITTALS:

A. General: Submittals shall be according to \[Section 01300 ‑
Submittals.\] \[and\] \[Section 01365 ‑ Certificates of Conformance.\]

B. Certificates of Conformance: Submit \[[ ]{.underline}\] copies of
written certification from the supplier of the Contractor‑furnished
items to be used on this project that they conform to the requirements
of this specification section.

C. Samples: Submit \[one\] sample of each color and texture of stucco to
be used on this project. Samples shall be 12 square inches. Samples
shall be actual material in colors required. Finished stucco work shall
match the approved sample panels.

1.4 DELIVERY, STORAGE, AND HANDLING:

A. Storage: Keep cementitious materials dry and stored off the ground,
under cover, and away from sweating walls and other damp surfaces until
ready to be used.

1.5 PROJECT AND SITE CONDITIONS:

A. Environmental Conditions: Maintain an ambient temperature of not less
than 40 degrees F continuously where stuccoing work will be done.
Maintain this temperature for not less than 48 hours prior to the
application of stucco, while the stuccoing is being done and during the
curing operation.

[PART 2: PRODUCTS]{.underline}

2.1 MATERIALS:

A. Portland Cement: Shall meet the requirements of ASTM C 150, gray
portland cement Type \[I,\] \[II,\] \[III\]; white portland cement, Type
\[I\] \[III.\]

B. Plastic Cement: Shall meet the requirements of ASTM C 150, Type \[I\]
\[II,\] except for the limitations on insoluble residue, air
entrainment, and additions subsequent to calcination. Plasticizing
agents may be added to portland cement Type \[I\] \[II\] in the
manufacturing process, but not in excess of 12 percent of the total
volume.

C. Masonry Cement: Shall meet the requirements of ASTM C 91, natural in
color.

D. Hydrated Lime: Shall meet the requirements of ASTM C 206, Type S.

E. Aggregates:

l\. ab Sand for Gypsum Base Coats: Shall meet the requirements of ASTM C
35.

2\. Sand for Gypsum Sand Float Finish: Shall meet the requirements of
ASTM C 35, natural color, and shall pass a No. 12 sieve.

3\. Sand for Portland Cement Lime Stucco: Shall meet the requirements of
ASTM C 144, except gradation of sand shall conform to the following
requirements:

4\. Sand Gradation for Basecoats:

Percentage Retained by (weight [+]{.underline} 2%) on each sieve

Sieve Size Min Max

No. 4 0

No. 8 0 10

No. 16 10 40

No. 30 30 65

No. 50 70 90

No. 100 95 100

5\. Sand Gradation for Finish Coats: Sand for finish coat shall be
natural color and shall be graded within the limits shown above for
basecoats, except that the sand shall pass the No. 8 sieve except for
smooth finish, when the sand shall pass the No. 30 sieve.

F. Water: Shall be clean and free from mineral and organic substances
which would affect the hardening or durability of the plaster or stucco.
Potable water is acceptable without testing.

G. Coloring: \[[ ]{.underline}\]

2.2 MIXES:

A. General: Except where otherwise specified, materials are specified on
a volume basis and shall be measured in approved containers, which will
ensure that the specified proportions will be controlled and accurately
maintained during the progress of the work. Measuring materials with
shovels \"shovel count\" will not be permitted. Ready‑mix stucco shall
be prepared for use by the addition of water only.

B. Mixing: Mix materials in approved, mechanical mixers of the type in
which the quantity of water can be controlled accurately and uniformly,
except that finish coats containing lime may be hand mixed. While the
mixer is in continuous operation, add approximately 90 percent of the
estimated quantity of water, half of the sand, all of the cementitious
materials, and the other one‑half of the sand shall be introduced into
the mixer in that sequence and mix thoroughly in the remainder of the
water until the mixture is uniform in color and consistency. Avoid
excessive mixing or agitation.

C. Portland Cement‑Lime Stucco Basecoats: Mix scratch coat in the
proportion of one part by volume of portland cement to not more than 3/4
parts by volume of hydrated lime and not less than 2‑l/2 nor more than 4
parts by volume of damp, loose sand. Mix brown coat in the proportion of
one part by volume of portland cement to not more than l/2 part by
volume of hydrated lime and not less than 3 nor more than 5 parts by
volume of damp loose sand. Workability shall govern the actual amount of
lime and sand used in the scratch and brown coats.

D. Plastic Cement Stucco: Mix scratch coat in the proportion of one part
by volume of plastic cement to not less than 2‑l/2 nor more than 4 parts
by volume of damp, loose sand. Mix brown coat in the proportion of one
part by volume of plastic cement to not less than 3 nor more than 5
parts by volume of damp, loose sand. Brown coat shall have the same
proportion of sand used in the scratch coat or a greater proportion of
sand than used in the scratch coat, within the limit specified.

E. Masonry Cement Stucco Basecoat: Mix scratch coat in the proportion of
one part by volume of masonry cement to not less than 2‑l/2 nor more
than 4 parts by volume of damp, loose sand. Mix brown coat in the
proportion of one part by volume of masonry cement to not less than 3
nor more than 5 parts by volume of damp, loose sand. Brown coat shall
have the same proportion of sand used in the scratch coat or a greater
proportion of sand than used in the scratch coat, within the limit
specified.

F. Finish Coat Proportions:

1\. Portland Cement Lime Stucco Finish Coat: Mix finish in the
proportion of one part by volume of portland cement to not more than one
part by volume of hydrated lime, and not more than 4 parts by volume of
damp, loose sand. Workability shall govern the actual amount of lime and
sand used in the finish coat, within the limits specified herein.
Approved coloring compounds shall be added to produce the required
color. Prepared stucco finish containing not less than l/3 portland
cement by weight may be provided, as approved.

2\. Plastic Portland Cement Stucco Finish Coat: Mix finish coat in the
proportion of one part by volume of masonry cement to not less than
2‑l/2 nor more than 3 parts by volume of damp, loose sand.

[PART 3: EXECUTION]{.underline}

3.1 EXAMINATION:

A. Requirements: Check metal grounds, corner beads, screeds, and other
accessories carefully for alignment before the work is started. Do not
apply stucco to surfaces containing frost.

3.2 PREPARATION:

A. General: Clean the surfaces to which stucco is to be applied of dust,
loose particles, grease, bond breakers, projections, and other foreign
matter. Do not apply stucco directly to (l) surfaces of masonry or
concrete that have been coated with bituminous compound or other
waterproofing agents, or (2) to surfaces that have been painted or
previously plastered. Before stucco work is started, wet masonry
surfaces thoroughly with a fine fog spray of clean water to produce a
uniformly moist condition. Lathing and accessories are specified in
Section 09207 ‑ Metal Lath.

3.3 APPLICATION:

A. General: Stucco may be applied by hand or by machine. When a
plastering machine is used, the fluidity of portland cement‑lime stucco
shall be controlled to have a slump of not more than 2‑l/2 inches when
tested using a 2 by 4 by 6 inch high slump cone. Subsequent to
determining water content to meet this slump, do not add additional
water to the mix. Conduct the slump test according to the following
procedure:

1\. Place cone on level, dry, non‑absorptive base plate.

2\. While holding cone firmly against base plate, fill cone with plaster
taken directly from the hose or nozzle of the plastering machine,
tamping with metal rod during filling to release air bubbles.

3\. Screed off plaster level with top of cone. Remove cone by lifting it
straight up with a slow and smooth motion.

4\. Place cone in vertical position adjacent to freed plaster sample,
using care not to jiggle base plate.

5\. Lay a straightedge across top of cone, again being careful not to
vibrate cone. Measure slump in inches from the bottom edge of the
straightedge to the top of the slumped plaster sample.

B. Workmanship: Apply stucco in three coats as follows:

1\. Base coats shall be applied with sufficient pressure and stucco
shall be sufficiently plastic to provide a good bond to bases. Base
coats shall be worked to screeds at intervals of from 5 to 8 feet.
Finish stucco work level, plumb, square, and true, within a tolerance of
l/8 inch in 8 feet, without waves, cracks, blisters, pits, crazing,
discoloration, projections, or other imperfections. Form stucco work
carefully around angles and contours, and well up to screeds. Special
care shall be taken to prevent sagging and consequent dropping of
applications. There shall be no visible junction marks in finish coat
where one day\'s work adjoins another.

C. Portland Cement‑Lime Stucco: Apply base coats with sufficient
pressure to curl the keys around the back of metal lath and to provide a
good bond on masonry.

1\. Stucco: Apply in three coats to a thickness of not less than 7/8
inch. Apply the scratch coat not less than 3/8-inch thick, lightly score
horizontally, and moist cure for not less than 24 hours. Apply the brown
coat after the scratch coat has been aged at least 24 hours in addition
to the moist curing period. Apply the brown coat to bring the base coat
out to the screeds, compact and straighten to a true surface with road
and darby, and float to receive the finish coat. After the brown coat
has been moist cured for not less than 24 hours and aged at least an
additional 5 days, apply the finish coat to a thickness of not less than
1/8 inch. Where any previous coat has become dry, dampen the surface
evenly with water, prior to the application of the next coat. Finish
coat for stucco shall be of the color and texture selected. Moist cure
stucco for 24 hours using a fine fog spray of water and apply to the
finish coat as frequently as required to prevent dry‑out of the stucco.
Do not stucco to the point where free water stands on the surface.
Prevent staining of the finish coat.

3.3 CLEANING:

A. General: Remove stucco droppings or spatterings from surfaces. Remove
protective covering from floors and other surfaces, and rubbish and
debris from the building.

B. Patching: Upon completion of the building, cut out and patch loose,
cracked, damaged, or defective stucco. Patch shall match existing work
in texture, color and shall be finished flush with stucco previously
applied. Do pointing and patching of stuccoed surfaces and stucco work
abutting or adjoining other finish work in a neat and workmanlike
manner.

C. Finishes: Leave clean, exposed stuccoed surfaces, in condition ready
to receive paint or other finish.

[PART 4: MEASUREMENT AND PAYMENT]{.underline}

4.1 METHOD OF MEASUREMENT:

A. Units: The work described in this section will not be measured for
payment.

4.2 BASIS OF PAYMENT:

A. Payment: No direct payment for the work described under this section
will be made. The Contractor shall include consideration for this item
in the bid price for other items of the Contract.

END OF SECTION