About This Property
After being converted into a duplex, this 1975 home has undergone full remodel. A building performance inspector has been hired to assess house condition. ACH50 blower door test has been performed and air leakage has been measured and infiltration areas were identified using a thermal camera. As expected excessive air leakage has been observed around single hung windows, bottom wall plates and roof rafters wall penetrations. Upon removal of the weathered cedar siding, a deteriorated polyethylene vapor barrier has been found underneath. Since foil faced fiberglass insulation was used inside wall cavities, polyethylene sheeting should not be installed on the outside of the walls. This method severely limits drying potential of the walls and can cause problems. House has been sheathed with plywood and with fiber board. Fiber board has been replaced with OSB sheathing and upon removal several uninsulated stud cavities were found. The ACH50 test has shown more than 15 air changes. Exact number could not be determined as the blower fan was not powerful enough to achieve 50 Pascals of negative pressure due to extreme air flow. Such extensive leakage provided for excellent drying potential of the walls and has resulted in no mold or rot being observed. This came at high energy cost, with electric bills during coldest months exceeding $600. Since remodel plans called for a layer of continuous insulation it was very important to ensure that walls stay dry as there won't be much drying potential due to air leakage upon completion. House has been wrapped with Tyvek building wrap and windows have been detailed with zip stretch tape. To further improve air tightness all seams have been taped. A 1" layer of continuous insulation has been installed over the building wrap. We have used XPS foam as it has a good insulating value of R5 and as it is class II vapor retarder with permeability of 1.1 perms. This allows for limited drying potential to the exterior through the building wrap and the insulation. We have used closed cell spray foam between exterior foam boards and rafters and soffits to further tighten up those problem area. Prior to remodel a day light could be observed between rafters and the trim in the master bedroom. Such conditions are not uncommon in houses built during the 70s and 80s.
New U32 energy efficient windows have replaced original wood windows. We have used either casement, awning or picture windows instead of original single hung windows in order to reduce air leakage in the long term. Environmentally friendly LP Smart side, prefinished siding has been chosen for their 15 year no paint maintenance warranty. This siding is free of Hazardous Air Pollutants and has very low VOC emissions.
Original electric baseboard heaters have been removed and replaced with mini split system heat pump for heating and cooling and gas fired hydronic heating system. Mini splits installed in the upper level will allow for a comfortable, cool environment during the summer and can be used to heat upper levels of the house during the shoulder season. High efficiency of the heat pump allows for heating and cooling that uses less energy than gas alone. Since the system is not designed or sized to provide enough heat during the colder days, high efficiency gas boiler will take over and supplement heat needed. If occupants decide to turn off mini split unit(s), then the system will operate the same as if the gas boiler is the only source of heat. Last item that got updated was the living room fireplace. Dated moss rock has been removed and clean looking limestone has been installed around the direct vent fireplace. This fireplace does not use interior air for combustion thus reducing likelihood for carbon monoxide gas entering the home. To further enhance safety of the occupants and to comply with building code, smoke detectors have been installed in the bedrooms that did not have one and combination carbon monoxide/smoke detectors have been installed adjacent to the bedrooms. Attached garage had drywall, but the seams were not sealed. This presented a potentially dangerous condition where dangerous exhaust gasses from the running vehicle in the garage could enter the home. This has been corrected by taping all drywall seam and sealing plumbing penetrations with fire rated spray foam.
Hollow painted interior doors have been replaced with solid wood alder doors and trims giving this home a clean mountain feel. Non-conforming garage door was replaced with code compliant, sealed and 20 minute fire rated door with self closing hinges. We have removed all of the carpets. Bedrooms have got updated carpet and paddings. Living and dining area got a new engineered hickory hardwood floor. This floor has high tolerance to the humidity change resisting shrinkage and formation of gaps. Living room, entry and loft walls and ceilings were finished with stained t&g pine planks. Amount of wood in the living room was a bit overwhelming, especially after the carpet has been replaced with hardwood floors. To break up all the wood visible from the living room and to achieve a cleaner look, we have removed some of the T&G from the living room walls and replaced it with drywall. This opened up the space and gave it a bit more modern look.
The result was a charming, cozy mountain home. Post remodel ACH50 test showed 3.7 air changes, a significant improvement in energy efficiency. In combination with a new heating and cooling system, this 1970s home got transformed to a comfortable, more efficient home that can last for many more decades to come.