A-A-272 Caulking CompoundsThis Commercial Item Description covers three types of 1-part caulking compounds suitable for use as recommended by the manufacturers for sealing, caulking, filling, leveling and glazing in general exterior architectural service and structures.

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November 22, 2005

SUPERSEDING

A-A-272A

June 7, 1995

COMMERCIAL ITEM DESCRIPTION

Caulking Compounds

The General Services Administration has authorized the use of this commercial item description by all federal agencies.

1. SCOPE.             This Commercial Item Description covers three types of 1-part caulking compounds suitable for use as recommended by the manufacturers for sealing, caulking, filling, leveling and glazing in general exterior architectural service and structures. Unless otherwise specified, these requirements are predicated on caulking applied to maximum joints 0.375” deep, filled by either cartridge injection or hand spatula.

2. CLASSIFICATION.

2.1 Type II – Siliconized Acrylic Latex caulk is water based. Acrylic caulks have fair adhesion  to most building materials and are available in a wide range of colors. Acrylic based caulks are  not true elastomers and tend to lose flexibility after a few years of outdoor exposure. Acrylic  caulks are paintable with both oil and water based paints.

2.2 Type III – Butyl Rubber is a true elastomer caulk. Butyl rubber is solvent based. Butyl               rubber caulk has excellent adhesion to most building materials. Butyl rubber is suitable for extreme outdoor exposure to water, sunlight, high and low temperature and expansion joint movement due to wind-loading or setting. Butyl rubber caulking can be applied in more inclement weather and is paintable with either solvent or latex paints.

2.3 Type IV – 100% Silicone caulk is a true elastomer caulk. Silicone caulk adheres to most building materials, and has excellent adhesion to glass. Silicone caulk is suitable for extreme outdoor service exposure to water, sunlight high and low temperatures and expansion movements. Silicone caulks generally require adhesion primers for paint to adhere.