First we need to do Examination of joint sealant for architectural work. Joints indicated to receive joint sealants shall be examined with installer present, for compliance with requirements for joint configuration, installation tolerances, and other conditions affecting joint-sealant performance. Installation shall be started only after unsatisfactory conditions have been corrected.
Installation Preparation for Joint Sealant
- Joints shall be surface cleaned immediately before installing joint sealants, in accordance with joint sealant manufacturer’s written instructions and the following requirements:
a. All foreign material that could interfere with adhesion of joint sealant shall be removed from joint substrates, including dust, paints (except for permanent, protective coatings tested and approved for sealant adhesion and compatibility by sealant manufacturer), old joint sealants, oil, grease, waterproofing, water repellents, water, surface dirt, and frost
b. Porous joint substrate surfaces, for example concrete, masonry and unglazed surfaces of ceramic tiles, shall be cleaned by brushing, grinding, blast cleaning, mechanical abrading, or a combination of these methods, to produce a clean, sound substrate capable of developing optimum bond with joint sealants. Loose particles remaining from above the cleaning operations shall be removed by vacuuming or blowing out joints with oil-free compressed air.
c. Laitance and form-release agents shall be removed from concrete.
d. Nonporous surfaces, for example metal, glass, porcelain enamel, and glazed surfaces of ceramic tiles, shall be cleaned with chemical cleaners or other means that do not stain, harm substrates, or leave residues capable of interfering with adhesion of joint sealants.
- Joint substrates shall be primed where recommended in writing by joint sealant manufacturer, based on preconstruction joint-sealant-substrate tests or prior experience. Primer shall be applied in conformance with joint sealant manufacturer’s written instructions. Primers shall be confined to areas of joint-sealant bond. Spillage or migration onto adjoining surfaces shall not be allowed.
- Masking tape shall be used where required to prevent contact of sealant with adjoining surfaces that would otherwise be permanently stained or damaged by such contact or by cleaning methods required to remove sealant smears. Tape shall be removed immediately after tooling, without disturbing joint seal.
Joint Sealants Installation
- Joint sealants shall be installed in accordance with manufacturer’s written installation instructions for products and applications indicated, unless more stringent requirements are included in drawings.
- Joint sealants shall be installed in accordance with ASTM C 1193.
- Acoustical sealant application shall be in accordance with ASTM C 919.
- Sealant backings of type indicated shall be installed, to support sealants during application, and at position required to produce cross-sectional shapes and depths of installed sealants relative to joint widths that allow optimum sealant movement capability.
- Gaps shall not be left between ends of sealant backings.
- Sealant backings shall not be stretched, twisted, punctured or turn.
- Absorbent sealant backings that have become wet shall be removed before sealant application, and replaced with dry materials.
- Bond-breaker tape shall be installed behind sealants where sealant backings are not used between sealants and back of joints.
- Sealants shall be installed at the same time backings are installed, and shall be installed by proven techniques, to comply with the following:
a. Sealants shall be placed in a way that they directly contact and fully wet joint substrates
b. Recesses provided for each joint configuration shall be completely filled
c. Uniform, cross-sectional shapes and depths relative to joint widths shall be produced, that allow optimum sealant movement capability.
- Immediately after application of nonsag sealants, and before skinning or curing begins, sealants shall be tooled according to the following requirements, to form smooth, uniform beads of configuration indicated; to eliminate air pockets; and to ensure contact and adhesion of sealant with sides of joint:
a. Excess sealants shall be removed from surfaces adjacent to joint
b. Only tooling agents that are approved in writing by sealant manufacturer, and that do not discolor sealants or adjacent surfaces, shall be used
c. Joint configuration shall be in accordance with drawings and ASTM C 1193.
d. Masking tape shall be used to protect adjacent surfaces of recessed tooled joints