Insulate & Air Seal Foundation and Basement Windows A significant portion of the basement foundation is exposed above grade with no meaningful Rvalue and opportunities for air infiltration. A primary air sealing and insulation approach using closed-cell spray foam is to be implemented. The basement is approximately 30’x46’x7’8” with a 5’x15’ crawlspace and 7’x10’ bathroom area that bump out on the east and west elevations, respectfully. 1. Materials a. Foamed-In-Place Insulation: Closed cell polyurethane foam. i. Shall have a minimum R-value of 6.0 at 1 inch thickness when tested in accordance with ASTM C518. ii. Shall utilize a blowing agent of water or non-ozone-depleting gas. iii. Shall have a maximum air permeance of 0.02 cfm per square foot when tested in accordance with ASTM E2178. iv. Basis of design material is Carlisle Spray Foam Insulation; Sealtite Pro HFO. Equal substitutions will be considered. b. Plywood i. Shall be ¾” thickness, ii. Shall be CDX for interior applications and marine grade for exterior applications. iii. Window openings (where plywood will be used) are 37” x 30”. Qty: 9 c. Miscellaneous i. Fasteners & Adhesives ii. 100% Silicone Sealant iii. Backer Rod iv. Intumescent Paint (or similar thermal barrier as deemed necessary by AHJ) v. Exterior Grade Paint 2. Installation a. Prior to commencement of any work, request hygrothermal modeling results (if any were obtained by the town) of brick wall assembly and review. Levels of insulation deemed safe for the wall assembly, as identified by the report, should be observed and override any placeholder R-values/thicknesses identified within this scope of work. The R-values identified herein should be considered maximums. If the hygrothermal modeling report deems the brick masonry wall unsafe for ANY level of insulation, then this scope of work will not proceed. b. Remove all exterior plywood infills where they currently exist and replace with new marine grade plywood. Paint to match existing color and seal perimeter of plywood to masonry opening with 100% silicone sealant. If plywood mounting allows for accommodation of a perimeter gap for backer rod, include backer rod for proper sealant installation. c. On the interior, fasten or adhere CDX plywood panels over all window openings. Panels should span and fasten/adhere onto surrounding brick, not direct to window units themselves. This allows for easier maintenance/replacement of window units from the exterior in the future, if necessary. The outside face of the plywood should be painted black so that raw plywood is not visible from the exterior. d. Isolate the basement as necessary to protect building occupants on the floor above from Volatile Organic Compounds released in the application and cure of spray foam. Isolation may include vacancy of the building during application and for a period thereafter. Contractor is to advise the Town and building occupants. e. Install a vapor barrier over the brick wall from the floor above and lap it over the existing vapor barrier on the stone foundation. The plywood window covers should also be covered with a vapor barrier to act as a release layer for the spray foam.
