This clients primary concerns for having an Energy Audit and subsequent Weatherization solutions were improving overall energy inefficiencies and seasonal comforts. Like many other home owners, they new their home was insulated with ample amounts of fiberglass batting, they just couldn't understand why there home was hot in the summer, cold in the winter, and why their bills were so high. They even installed a metal roof as they were tired of dealing with ice damming issues.
The primary issues within this home were basement and attic flat solutions, which have been covered within this websites blog and other case studies, but also a cathedral ceiling problem that we see far too often.
We've talked at length of the issue's concerning fiberglass insulation and air leakage. This home has a one story addition with a vaulted/cathedral ceiling leading into an attic flat, and is finished with Tongue & Grove (photo above). They were having some water staining issues on the T&G (left photo) and overall poor seasonal comforts within this section of the home.
Most weatherization solutions revolve around some mixture of air sealing, managing airflow, and installing proper insulation. This specific vaulted ceiling scenario involved them all. The photo to the right shows soffit venting leading into a rafter cavity which is filled with fiberglass insulation. The idea is that this ventilation is needed to keep the roof-deck cool preventing things like ice dams. What it actually does is allow cool air to enter fiberglass insulation, effectively devaluing R Values, which then allows heat to conduct through the roof and escape the house. This cool outdoor air can also enter the home though the unsealed Tongue & Grove material creating uncomfortable living conditions (see photos below).
T&G does NOT air seal, therefore the actual air sealing or air/vapor barrier should be right behind the T&G. These photos show the transfer of energy through the T&G - no wonder they were cold in the winter and hot in the summer! Since this audit was done in the fall we are shown warmer temperature points, but in heating season conditions these temperature marks could easily be the same as the outside temperatures (imagine 0°). The T&G water stains shown earlier are from condensation issues related specifically to heat loss. As the thermal photos show, energy is easily transferring through this cathedral ceiling area. In fact, warm air is leaking through the T&G joints and hitting the cold surfaces due to the Soffit Venting, which then leads to condensation and water staining.
- Remove all existing Tongue & Grove material and fiberglass insulation within the rafter cavity
- Install eave end blockers foam sealed in place to block airflow from entering the rafter cavities OR remove soffit venting and install solid soffits. NOTE: we installed the air tight blockers (2" rigid board) foamed in place as the rafter cavity overhang was large and we didn't want to fill the entire cavity with insulation - had the eave overhang been smaller we most likely would have installed solid soffits and closed cell foam from the inside
- Install at least 5" closed cell spray foam into rafter cavity creating a vapor and air barrier
- Install new T&G, drywall, or whatever finish product you desire.
- Enjoy your new comfortable home!
Photos Below: closed cell spray foam installed in the manner listed above.
Side note - had they proceeded with these weatherization solutions prior to installing a new metal roof, they would have seen ice damming issues solved