C402 Sealing Cracks and Joints in Concrete Floors and Walls

Cracks and joints with widths less than ¹/₁₆ inch (1.6 mm) shall be repaired by the application of an elastomeric material capable of withstanding at least 25-percent extension and extending at least 4 inches (102 mm) beyond the length and width of the crack, or by the method described in Section C402.2.

Cracks with widths larger than ¹/₁₆ inch (1.6 mm) shall be enlarged to a recess with minimum dimensions of ¹/₄ inch by ¹/₄ inch (6 mm by 6 mm) and sealed with an approved caulk or sealant applied over a sealant backer in accordance with the manufacturer's recommendations. Cracks and joints with widths less than ¹/₁₆ inch (1.6 mm) may also be sealed in this manner if traffic, floor covering material or other conditions are inconsistent with the provisions of Section C402.1.

Where large openings through the slab exist, such as at a bath tub drain or a toilet flange, an acceptable method for sealing the exposed soil shall include fully covering the exposed soil with a solvent-based plastic roof cement or other approved material in accordance with Section C405.1 to a minimum depth of 1 inch (25 mm). Where voids between masonry foundation walls and the slab edge are accessible, and are sealed in order to reduce radon entry, nonshrinking cementitious material may be used.

Utility penetrations or other openings through hollow cavity walls that separate conditioned space from soil, or conditioned space from a crawl space, shall be sealed with an approved material on both the interior and exterior faces of the wall. Penetrations and openings through solid concrete floors or walls may be sealed on only the interior face.

All openings for electrical boxes or plumbing or other wall penetrations in hollow masonry walls, that are sealed in order to reduce radon entry, shall be sealed with an approved caulk and/or gasket on the interior face of the wall.

Any sump located in a conditioned portion of a building, or in an enclosed space directly attached to a conditioned portion of a building, shall be covered by a lid. An air tight seal shall be formed between the sump and lid and at any wire or pipe penetrations.