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10 Answers

Confused and worried about minisplit sizing

We’re building a house in Toronto, two stories (both about 1500 sqft each), first floor R26, second floor R32, second floor ceiling R70, with HRV, de-humidifying system, window-to-wall ratio 12%, windows mostly face east and west, windows are Fibertec high-efficiency, fiberglass frame, low e-coating. Whole house will have hydronic floors for heating. We’re planning Mitsubishi mini-splits for A/C, but we’re very confused about sizing and placing of heads (and outdoor units).

Asked By Thomas Kaempfen | Jul 9 17
3 Answers

Hardie lap siding vs. Boral siding

We are building a house in NH. Hardie is less expensive material, but more expensive labor. What about durability? Hardie has had a bad reputation. Have they improved their product? We can't find how long Boral has been available. Any word on problems with Boral?

Asked By Frank Torti | Jul 10 17
2 Answers

Accessing isolated part of attic

In all areas of my attic where the main attic/roof intersects a section of the roof with a perpendicular gable (e.g. at a dormer), there is an access opening for that sub-section of the attic. There is one exception, and I want to safely access the isolated section.

I can tell by both measurements from the center of the main roof, as well as confirmation by the absence of roofing nails, the section I need to cut, but I was wondering if anyone had any other tips on what I need to be careful of before cutting.

Asked By David Johnson | Jul 3 17
5 Answers

Water infiltration/condensation problems


The climate zone where my bulding is, is 7or 7A, It is located in the southern part of province of Quebec, Canada, village name is Saint-Philemon.

The buiding is 2 stories, 28x24 floor surface, south wall on each story has 2 windows 9'x7'.

Wall layers from exterior are : wood clading, wood lathe(1x3), air barrier, styrofoam (2''), sheating OSB 5\8, 2x6 spruce wall filed with mineral wool, plastic vapor barrier, wood lathe(1x3), sheatrock/gypsum.

Asked By PIERRE LEVASSEUR | Jul 1 17
5 Answers

Dealing with multiple WRBs and air barriers with external foam board

Building a home on the edge of zone 4 & 5 (in zone 5) with avg 60" annual rainfall and minimal snow. CA building prices are crazy (~$275/sqft by avg contractor in area), and this is our final home so want to maximize durability and longevity in a reasonably buildable green home. The buildable area on the lot is small, so need a thin wall to get the needed square footage while allowing a garage. Planning 2" PolyIso over 2x4 framing and 7/16 OSB, then 1x4 rainscreen and stucco for the walls.

Asked By Mitchell Costa | Jun 29 17
4 Answers

Insulating a 1930s home with foam and fiberglass


I have gutted my bathroom of my 1930 cape cod and am looking to insulate from the inside.

I live in zone 5a, upstate NY
The house exterior is brick, with a gap between the brick and the exterior sheathing ( which is 8 inch boards)

My thoughts are this

Asked By Jason A | Jun 26 17
5 Answers

Concrete slab reinforcement: M100 vs. F100 fibers: finish and strength

My concrete contractor has 2 fiber choices for the slab pours : M100 and F100 from BASF. Both are polypropylene fibers, the difference is the size.

Officially M100 is only to be used to prevent shrinkage cracking. Unofficially it has been used (with apparent success) to replace light wire mesh in slabs poured in Southern Ontario. Concrete contractors prefer it when a smooth finish is requested as the extra fine fibers make the slab easier to finish.

F100 is a larger fiber, that is approved by BASF to replace light gauge wire mesh. There is no question this is the robust choice.

Asked By Mai Tai | Jun 25 17
3 Answers

Dense packing a flat roof

Hi Recently I've been wanted to upgrade my insulation as my house was built in 1975 and I'm sure the insulation is not pulling its weight.. I got an estimate from an insulation installer who said that they can take of the fascia board vent screens and put in and blow in cellulose and pack it in in the flat part of the roof. I asked him about moisture and vapor issue and he said that it wouldn't be an issue. Although I am a bit hesitant on this as I'm sure it will be an issue down the road. I was wondering if some of the experts can lead more info on this situation.

Asked By Beach13 | Jun 25 17
15 Answers

Frost wall foundation details for stone and siding construction

I am planning a slab on grade build (24"X8" footings, 4' deep, with 4'6" frost walls). I am having issues with the location of all the sub components on the frost wall width, specifically on the stone detail wall (front wall only).

Asked By Mai Tai | Jun 18 17
2 Answers

Spraying vapor barrier paint on open-cell foam


I want to use open-cell foam on a new project and am trying to meet the IRC guidelines. The insulation installer suggests spraying vapor barrier paint directly on the foam. I have read previous research on GBA that found this ineffective. However, would it also be detrimental to the performance of the foam, or would it make no difference?



Asked By user-6868809 | Jun 16 17
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