07900.doc

SECTION 07900

PART 1

GENERAL

1.1 DESCRIPTION OF WORK

A. Caulking and joint sealing work.

1.2 JOB CONDITIONS

A. Examine joint surfaces and backing, and their anchorage to the structure, and the conditions under which the joint sealer work is to be performed, to determine whether conditions are detrimental to the performance of the sealers. Do not proceed with the joint sealer work until unsatisfactory conditions have been corrected in an acceptable manner.

B. Weather Conditions: Do not proceed with installation of sealants under adverse weather conditions or when temperatures are below or above manufacturer’s limitations for installation. Proceed with the work only when forecasted weather conditions are favorable for proper cure and development of high early bond strength.

1.3 SUBMITTALS

A. Manufacturer’s data on each type sealant listed, including backstop material, primer and sealer. Certificates of compliance stating that caulking and sealants conform to the specified requirements.

PART 2

PRODUCTS

2.1 MATERIALS SCHEDULE

A. Caulk and seal joints and embed materials in accordance with following schedules. In general, use gun grade materials for vertical joints and pour grade for joints in horizontal plane. Colors shall match or be compatible with adjacent surfaces as approved by the Contracting Officer.

1.

Polyurethane Sealant

Joints between:

a.

Masonry control joints

b. Joints up to 25% anticipated movement

2. Silicone

Gutter joints

b. Flashing connections to ductwork c.

Joints up to 50% anticipated movement

3.

Silicone Modified Acrylic

Interior door frames

b. Surfaces requiring painting c.

Joints with up to 7.5% anticipated movement

2.2

DELIVERY AND STORAGE

A.

Deliver materials to the job in manufacturer's original unopened containers.

1 .

The containers shall include the following information on the label, supplier, name of material, formula of specification number, lot number, color, date of manufacture, mixing instructions, shelf life, and curing time when applicable at the standard conditions for laboratory tests.

B.

All materials shall be carefully handled and stored to prevent inclusion of foreign materials, or exposure to temperatures exceeding 90 degrees F.

1 .

Caulking compound or components outdated as indicated by shelf life shall not be used.

2.3

SEALANTS:

A.

Silicone: One part product meeting requirements of Federal Specification TT-S-00230C

Tremco "Spectrem 1", Dow "791", Bostik "Chem-Calk 1200".

B.

Polyurethane: One part product meeting requirements of Federal Specification TT-S230C.

Tremco "Dymeric", Pecora "Dynatrol", Sonneborn "Sonolastic NPl"

C. Acrylic latex: Product meeting requirements of ASTM C-834.

Tremco "834", Bostik "Chem-Calk 600", or approved equal.

D. Back-up Materials- Closed cell resilient foams, flexible tubes or beads, jute or oakum, as required for proper caulking of joints. Back-up shall be clean, free of oil grease, or other substances that might stain or otherwise harm the effectiveness of the sealant.

E. Bond-Preventive Materials: Wax Paper, Aluminum foil, polyethylene tape or other material approved by sealant manufacturer.

F.

Other Caulking Accessories: Primers, admixtures, bedding tapes and similar materials, used as a part of caulking system shall be products recommended by the sealant manufacturer for use with his product.

PART 3

EXECUTION

3.1

APPLICATION

A.

Execute work in compliance with the sealant manufacturer's printed direction. Assure that all surfaces are clean and dry, and that the brushes, rags and solvent used for cleaning are free of oil and grease.

1.

Caulk only when the ambient temperature is over 40 degrees F.

2.

Caulk joints with complete adhesion on both sides of the joint and with bond break at the back of the joint.

3.

Tool joints to assure full compact joints with optimum adhesion.

4.

Caulk at such times as to prevent blowing dust from adhering to surface of bead before it skins over.

5.

Cover bead for protection where necessary.

3.2

SURFACE PREPARATION

A.

Masonry and Concrete: Remove all loose particles, curing compounds, frost, oil, grease and other foreign matter. Remove soluble alkaline salts by washing With 5% solution of muriatic acid, rinsed with clear water and dried. Sand blast or power sand surfaces that have absorbed oil to insure clean surfaces.

B.

Metal: Remove surface coatings or corrosion by sand blasting, wire brushing or chemical cleaners recommended by the manufacturer. When chemical solvents are used wipe the surface clean and dry with drying cloth while the surface is wet with solvent.

C.

Galvanized Metal: Neutralize with acid.

D. Wood: Sand or scrape surfaces to remove foreign material and expose clean firm wood.

E. Aluminum: Remove corrosion with aluminum wool or suitable rubbing wheel. Do not damage or mar exposed finish

3.3

PRIMER

A.

Shall be used on concrete masonry units, wood, or other porous surfaces in accordance with instructions furnished with the sealant. Primer shall be applied to the joint surfaces to be sealed. Surfaces adjacent to joints shall not receive primer.

3.4

BOND BREAKER

A.

Where necessary, apply suitable bond breaker to prevent bond between back of the joint and sealant.

3.5

BACKING

A.

Fill joints with compatible backing so that sealant size will meet the following requirements:

1.

Minimum Width: Unless otherwise detailed, not less than 1/4".

2.

Ratio of Depth to Width: For widths up to 1/2" equal; and for widths over 1/2" depth approximately 1/2 the width but in no case less than 1/2".

3.6

MASKING

A.

Apply masking tape along side of exposed joints as required to avoid contamination of adjacent surfaces. Do not touch cleaned and primed surfaces with masking tape as oils from tape may impair adhesion. Remove tape immediately after the bead or tooling is finished and before surface skin has started to form.

3.7

CURING

A.

Accelerate cure, where needed, by treating joint with fine spray of water or otherwise as recommended by the manufacturer.

3.8

CLEANING

A.

The surfaces adjoining the caulked and sealed joints shall be cleaned of smears an other soiling resulting from the caulking and sealing application as work progresses.

3.9

WORKMANSHIP

A.

Only experienced, qualified contractors shall perform the work described under this section.

B.

Joints shall not be sealed until they are in full compliance with the drawings, and have been approved by the Contracting Officer.

3.10

OTHER TRADES

A.

Other trades will be coordinated by the General Contractor in order to avoid damage to a completed, sealed joint.

B.

Caulking done by the painter in preparation for final painting shall not be considered as meeting the requirements of this section.

END OF SECTION

07900 - 5 H:\8348\8348003.23\Docs\B-3 Specs\Division 7\07900.doc November 1, 2005