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1 Answer

Does anyone have experience with or an opinion of the Dow Powerhouse solar shingle and cathedral ceilings/ roofs?

The cathedral ceiling/roof is unvented, closed cell insulated. Will this solar shingle properly vent moisture upward from the plywood decking? Will there be any problems with running the multiple wiring conduits to the inverter in the basement?

In Green products and materials | Asked By JOSEPH POLAND | May 16 13
3 Answers

Re-using brick pockets in an exterior wall

I am working on the design phase of a rowhouse renovation in Baltimore, Maryland. This rowhouse is 14'x50' and is an end-of-group, with an east facing exterior side wall. Existing floor joists sit in "brick pockets" in this exterior wall.

In General questions | Asked By Charles Chiampou | May 14 13
4 Answers

Can exterior foam be combined with interior spray foam?

If I have walls and/or an unvented cathedral ceiling that are insulated with closed-cell spray foam from the inside, can I also have rigid foam on the outside of the sheathing to limit bridging?
Just wondering if it's somehow a bad idea to have the sheathing sandwiched between two layers of foam.

Thanks, Chris.
(This is for Ottawa, Canada, equivalent to zone 6A.)

In Green building techniques | Asked By Christopher Solar | May 13 13
7 Answers

Thermal mass lessened with overlay over slab?

I have a passive solar off-grid home that works extremely well with a 2 in. concrete slab that is finished with decorative concrete stain/paint. However, the slab and stain/sealer are completely defective and very likely have to be replaced, but one party is proposing a concrete overlay product be put atop the existing slab. The overlay product (ArtCrete Deck Coat, I think it is) consists of two parts--1) Portland cement, aggregate, and a stain, and 2) a modified acrylic latex resin.

In Energy efficiency and durability | Asked By K Tot | May 13 13
3 Answers


I am finishing a screened porch into a fully-insulated room, to be part of the house and used year round. I understand Roxul is an excellent choice for exterior walls. Is a vapor barrier necessary and, if so, can someone suggest how to install. Tks for your help.

In General questions | Asked By Roni Collier | May 14 13
3 Answers

How to seal a Bilco door to prevent heat loss and moist air transfer?

We have a standard exterior Bilco door that leads to semi-finished space in our basement. We are having trouble with cold air coming in during the winter months and damp air in the spring/summer months. How can we seal this Bilco door without creating condensation issues around the door and/or seal? The air is coming from the cracks at the door hinges and around the doors themselves. It appears that the Bilco casing unit is sealed properly to the concrete. Home Depot sells polycarbonate domes that cover the doors.

In GBA Pro help | Asked By Jas Thurber | May 12 13
3 Answers

I was told that my central air conditioner needs a larger return duct

I was told that my central AC needs a larger return duct. The symptom was that the low pressure line at the compressor was icing up on the outside. Does this make sense? I had thought that if the system was low on freon that this was a symptom.

I am handy but need some input into the size requirements of a return duct versus the output ducts. I would assume them to be about the same size.

In Mechanicals | Asked By john friede | May 13 13
6 Answers

Spray-foam smell

Two weeks ago, We had Sealection 500 sprayed in wall cavities and under roof decking (metal roof) for our new home build. The smell seemed minor by 2 days after, then the ingition barrier - Blazelok IB4 was sprayed on entire roof deck. One week later, the smell is as bad a the day they sprayed the Blazelok IB4. Cure rate is 2-3 hrs so something seems wrong.
The chemical smell burns your eyes and nose, I can taste a metallic taste on my tongue and get dizzy after entering the home if any windows are closed.

In General questions | Asked By k s | Feb 25 11
2 Answers

Will some insulation need to be removed in a few years?

Our long-term plan is to add a deck/pergola/conservatory on top of a one-story room on our mostly two story house in Zone 5a. BUT, the roof on the single story leaks and will be unshingled/re-shingled NOW. We'll use this opportunity to remove decking of the flat part of the roof (it angles from the flat part down to the three walls), access the inaccessible attic, and air seal/insulate before re-shingling.

In General questions | Asked By Gordon B | May 13 13
12 Answers

Complaints about fiberglass windows — plus what is the next best thing?

We are building a house in Quebec province, Canada — so very cold winters and hot / sometimes humid summers. We were set on installing fiberglass windows triple / double panes according to exposure of lot (mainly southern and eastern with a little western and very little northern.)

In Green products and materials | Asked By Tango B* | Jan 22 12
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