BAP Weatherization & Retrofit Measures Flashcards

Which air sealing location typically provides the greatest energy savings in a typical US home?

Answer: Top plates and penetrations in the attic floor

Attic floor penetrations — around pipes, wires, and top plates — are major air leakage sites because the stack effect drives warm air out at the highest points of the building.

What is the primary function of a vapor retarder in a wall assembly?

Answer: To slow the diffusion of water vapor into or through the assembly

A vapor retarder limits vapor diffusion through a building assembly, reducing the risk of condensation and moisture damage within the wall cavity.

When insulating a rim joist in a conditioned basement, which approach is typically recommended by building performance standards?

Answer: Rigid foam board cut and air-sealed in place, or spray polyurethane foam

Rigid foam cut-and-cobble with foam sealant, or two-part spray foam, air-seals and insulates the rim joist simultaneously — a critical detail for basement energy performance.

What is 'thermal bridging' and why does it matter in retrofit insulation projects?

Answer: Heat conduction through structural members that bypass insulation layers

Thermal bridging occurs when conductive framing members — studs, joists, headers — bypass insulation, significantly reducing the effective R-value of the assembly.

A BAP analyst recommends dense-pack cellulose for an existing closed wall cavity. What tool is used to install it?

Answer: A high-pressure pump forcing cellulose through a fill tube inserted into the cavity

Dense-pack cellulose is installed by inserting a fill tube into small holes drilled in the wall sheathing or drywall and using a high-pressure blower to pack cellulose to 3.5 lb/ft³ density.

Which weatherization measure primarily addresses radiant heat gain through a ceiling rather than conductive heat loss?

Answer: Installing a radiant barrier on the underside of the roof deck

A radiant barrier reflects infrared radiation from the hot roof deck, reducing heat gain into the attic space in summer without improving conductive R-value.