24 CFR § 3285.804
Bottom board repair
February 22, 2021
(a) The bottom board covering must be inspected for any loosening or areas that might have been damaged or torn during installation or transportation. Any missing insulation is to be replaced prior to closure and repair of the bottom board.
(b) Any splits or tears in the bottom board must be resealed with tape or patches in accordance with methods provided in the manufacturers installation instructions.
(c) Plumbing P-traps must be checked to be sure they are well-insulated and covered.
(d) All edges of repaired areas must be taped or otherwise sealed.