For those of you considering a Deep Energy Retrofit of a solid masonry home, the folks at Building Science Corp offer a simple paper that covers many of the details that keep Torontonians awake at night. As Dr Lstiburek says in the foot notes, Chris Benedict has been doing DER of solid masonry buildings for years now in NY and is considered a pioneer in the ‘industry.’
The article falls short of detailing insulation and air barriers at the roof (few residential roofs have parapets), what to do about old masonry chimneys and how to deal with foundation renovation from the outside. Treatment of the latter can be found on the BSC web site when dealing with century old foundations. The ceiling to wall junction as well as chimney detailing however is an issue that needs to be addressed as air leakage and ice damning are significant threats that undermine any DER.
The advantages of exterior insulation are that its less disruptive to the occupants and allows the embedded floor joists to stay conditioned year-round. This last point is crucial and the risks especially to the main floor where the untreated wood mud sill is embedded into the masonry
Toronto homes have masonry going right up to the back side of the roof deck and the ceiling joists and roof rafters punctuate the air barrier depending on where its located for the ceiling. Using the exterior liquid applied air barrier on the face of the exterior brick wall, the continuity at the roof to wall junction might be detailed most successfully with the fewest penetrations if a hot roof is used and the detailing of these points would make for another BCS article!
Click on the link below to read the full article: