Insulation Services Case Studies: Super Kneewall in Rosendale, NY

Colette had received an energy assessment from another company prior to contacting Global Dwelling. She was confused by the first contractors recommendations and was unable to get a clear plan for the comfort problems she was experiencing in  her house. The original contractor was a window installer so the problems he found in her house was with the windows. He claimed that replacing her windows would improve her drafty rooms and reduce her oil usage by 50%. She wanted a second opinion so she got our name from a friend and gave us a call. We came out and did our usual thorough inspection of the home along with our diagnostic testing including a blower door and infrared scan of the home. What we found was that her cape style home was leaking air from more than just her windows. The knee wall attics were improperly sealed and insulated. Colette had paid a contractor a few years earlier to come in and blow cellulose onto the floor in the kneewall. The contractor installed 10" of cellulose but did not address any air sealing needs. The slopes in the closets were uninsulated and the wall adjacent to the knee wall was poorly insulated at best with fiberglass sporadically installed at not in contact with the wall surface leaving large gaps for air and heat to escape into the vented attic.

We prescribed a super knee wall repair to the area. First we removed the drywall in the closet and revealed the empty rafter bays. Once exposed we installed rafter baffles to maintain the ventilation to the upper attic and sealed around to prevent wind wash to the fiberglass insulation. We then installed 2" silver glo rigid insulation over the fiberglass and sealed the seams. This approach provides the highest amount of insulation while also maintaining ventilation which are essential to remove any moisture in the roof assembly and prevents condensation from forming.

We also went into the knee wall attic and attacked the wall adjacent to the closet and bedroom. We removed the fiberglass and installed rigid foam into the thin cavities and then covered the entire wall with another layer of rigid foam. All the seams were sealed to prevent drafts. Next we sifted through the cellulose on the floor to seal any electrical and plumbing connections as well as wall tops to properly seal this attic from the house.

Once we were satisfied with the repairs to the top of the house we attacked the basement. The walls were block and very porous. The rim joists were unsealed or insulated. Our solution was to install 2" Foamax insulation on the walls and in the rim joists. The heating system, which resides in the basement was no withing the insulation barrier and any heat lost from the pipes or the boiler itself was keep in the heated envelope of the house and not lost to cold block walls or leaky rim joists.

In the end no windows were replaced and Colette saw a 55% reduction in her oil usage over the next year. She has contacted us on several occasions to express her happiness with her now comfortable and significantly more energy efficient house.