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13 Answers

Check my wall strategy?

We're about to begin framing on a new house in zone 6A (Minneapolis). From months of reading and following posts here, I've devised what I think is a wall/insulation strategy that will work. Does this look right, or are there any tweaks that could make it:
a) perform better (within reason; we're going after the "pretty good" model, not a Passivhaus)
b) more cost-effective
c) easier to build

The concept (inside to out):
- Drywall
- 2x6 stud wall
- Membrain or similar (6-mil poly if the inspector insists...sigh)
- 5.5" blown fiberglass cavity insulation (BIBS) = R-23

In Plans Review | Asked By Joshua Wyatt | Jul 28 14
5 Answers

How can I remedy a cathedral ceiling with fiberglass batts in unvented rafter bays that now emits a strong musty odor?

Investigation revealed 3 problems: 1) no soffit vent; 2) insulation extending beyond the end of plastic rafter vents closing off the air channel up to the ridge vent; 3) no blocking above the wall to seal up the fiberglass. I've corrected the first two and caulked the ridge on the inside, but am unable to fix the blocking. The odor persists and I fear the fiberglass is contaminated with mold that the revived air flow won't be able to dissipate. Would pulling out the fiberglass (through the soffit to avoid major deconstruction) and filling the bays with foam work?

In GBA Pro help | Asked By Michael Roland | Jul 25 14
3 Answers

Irregular rafter spacing

My 1907 house has 2" x 4" rafters on 34" centers. After stripping to roof to the original 1 x 4 skip sheathing, I am planning to add 6" of polyiso foam and then a layer of plywood sheathing. The scrap rate is high if I have to cut every sheet to 48 x 70". Is there a precedent for using tongue and groove roof sheathing (assuming I can find it locally) without the seams landing on the rafters in this sort of application?

In Green building techniques | Asked By Keith Richtman | Jul 29 14
4 Answers

Long room minisplit installation location?

11' X 30' room. Fujitsu 9rls2h. The specifications shows the flow pattern is long and skinny. Would it be best to install at the middle of the long wall or install at the end on a short wall? There will be ceiling fans at the midpoint and at the point farthest from the minisplit if on a short wall.

In Mechanicals | Asked By Shawn Shumaker | Jul 28 14
2 Answers

I'm upgrading insulation in my 1940s Cape Cod near Washington, DC

A major source of heat loss/gain are the side east and west facing plaster & lathe side walls.

I've measured the temperature of those walls; they stay hotter than outside temps well into the night, and there's 5-10 degree increase as you go up the wall from floor to ceiling. They're actually hotter than ceiling and kneewalls alot of the time. There's also some moisture coming through; the plaster is rotted through under the window apron and there are cracks in the corners.

In General questions | Asked By Tomas Bridle | Jul 28 14
8 Answers

Powered attic ventilator with whole house fan

Hello, I really appreciate this website.

I understand that powered attic ventilators have a lot of problems. But my contractor is suggesting adding one to support a whole-house fan, due to the limited attic ventilation. (I do have some passive ventilation but not quite enough, and the gables are maxed out because it's a flat roof.)

So as long as I always run both fans at the same time, and as long as the cfm of the whole house fan exceeds the cfm of the attic fan, is there still going to be a problem?

Thanks!

In General questions | Asked By Robert Shelton | Jul 25 14
3 Answers

Foundation/floor strategy for a heated workshop in Zone 6A

I am planning a 30'x22' farm workshop in Eastern Ontario, Canada. I want to end up with a level floor suitable for woodworking machines (table and bandsaws, planer, jointer etc) , Floor will be on grade, location is on a small rise and I will make sure there is good drainage away from building. I will place 2" of SM insulation under floor. I will most likely frame double stud walls and insulate with 6" to 7" of Roxul.

In GBA Pro help | Asked By mark godfrey | Jul 26 14
6 Answers

Any way to abate thermal consequences due to required 2" termite inspection gap?

Hi All,

We are using Foamglas for insulating under our slab as well as the slab edges (monolithic slab on grade). It is a requirement to leave a 2" gap above the Foamglas on the slab edges for termite inspections. Are there any options to satisfy this requirement, but not have the thermal gap? Perhaps industrial strength velcro or something :) ?

Thank you,
Stacey Owens

In Green building techniques | Asked By Stacey Owens | Jul 18 14
8 Answers

What is a good, affordable construction detail (in terms of long-term UV and water protection and overall durability) for the popular contemporary horizontal, spaced cedar cladding look?

(Examples of what I am referring to can be seen at: http://vastern.co.uk/wp-content/uploads/2013/03/Splayed-cladding-detail.jpg AND http://www.bartonqualitytimber.co.uk/images/categories/chestnut%20claddi... )

I am not terribly conceded about the cedar: if it is stained all 6 sides with two coats and placed on black painted strapping, then it should handle the elements reasonably well. My main concern is what the substrate behind it should be.

In General questions | Asked By Burke Stoller | Jul 18 14
2 Answers

Tear-down with an existing uninsulated basement: convert to slab on grade?

This question might have an obvious answer, but I haven't been able to dig up anything on google. If I were to purchase a tear-down property that had an existing uninsulated, fieldstone basement, what would be the best course of action to build a high performance house? Fill it in with dirt then to then create a slab on grade? Tear out the fieldstone and use the existing cavity to create an insulated basement (while also hopefully re-using the fieldstone on site for something useful like a wall)?

In Green building techniques | Asked By Ethan Fahy | Jul 21 14
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