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5 Answers

Under cathedral ceiling - EPS or polyiso?

I have a vented cathedral ceiling that is as follows. I am in climate zone 5 so I assume this is an R-38 assembly:

1. Asphalt Shingles
2. Roof decking
3. 12" I-beam joists full length with styrofoam vent channels stapled to the underside of the decking
4. 10.5" fiberglass batts in between I-beams
5. Visqueen sheeting stapled up underside of I-beams over entire underside of roof.

In Energy efficiency and durability | Asked By Kyle S | Aug 18 16
4 Answers

Why do I have a musty mildew type smell in my conditioned crawl space?

The house we moved into is now 11 years old. We have been here for 2 years. Just this year we started having a mildew basement type smell coming into our first floor when we run the ac. It is summer and hot. We have a conditioned craw space that was put in when the house was built. There is not junk down there. We have a heat pump and ac unit and a gas furnace in the craw. Everything was fine until this summer when our first floor began to smell like a musty basement.

In General questions | Asked By linda larochelle | Aug 18 16
5 Answers

Replacing fiberglass with foam to save space

I'm trying to make room to run a 3.5" x 10" HRV duct in my new-build cathedral ceiling cape, unfortunately as a bit of an afterthought. Unfortunately, I don't have a convenient interior wall to use, so it needs to be installed in an exterior wall.
One way I can make room is to take one rafter bay and one stud bay and use RMax polyiso there instead of the fiberglass I will be using everywhere else. This way I can achieve approximately the same R Value in less space, freeing up room for the duct I wish to install.

In General questions | Asked By Justin Smith | Aug 18 16
1 Answer

SIPs or nailbase with spray foam?

I recently read an article from Building Science Corp regarding unvented ceilings. If I understand it correctly, if I use SIPs or Nail Base as the main insulation/structure of the roof, I can also add closed cell or open cell spray foam on the underside of the roof to increase the insulation. Is this correct? Is one foam better than the other? Could you also use any other type of insulation on the underside of the roof? I thought if you used insulation on the exterior of the roof, you needed to use an insulation that would allow the ceiling to dry inwards.

In Energy efficiency and durability | Asked By Kyle Rice | Aug 18 16
18 Answers

Attic insulation quandary

Seeking advice on renovation plans for a 1910 house in ND - Zone 7.

- 2 1/2 stories above ground with full basement.
- 2nd story has 'sun porch' facing south.
- 2 layers of siding. Inner layer has lead paint (of course)
- Insulated in the 70's with formaldehyde foam, holes drilled through exterior to fill cavities.
- High efficiency propane furnace, forced air.
- 2 chimneys.
- 1st in middle of house used for original oil-burner furnace and water heater. Now used by wood fireplace in basement.

In GBA Pro help | Asked By Tim Lange | May 16 16
3 Answers

Asphalt shingle failure mechanisms

I looked at a 13 yr old house yesterday and found most of the asphalt shingles were severely curled and, obviously, needing replacement. The roof was unvented and insulated below the deck (i.e., no foam on top) but I don't know much more than that. The undersides of the rafters in a small storage area were covered with rigid foam. I was wondering what possible mechanisms (besides cheap shingles) could lead to such failure after a pretty short period of time. Thanks for any and all ideas.

In Energy efficiency and durability | Asked By Rob Shuman | Aug 17 16
2 Answers

I have a concrete floored, plaster walled bathtub alcove that I want to remodel into a curbless shower or wet room.

The condo building was built in 1959, and my unit was gutted by building management in 2014. The tub had been removed and drywall installed in the lower 18" of the alcove below the existing plaster which is on metal lath. (I have removed the drywall and replastered the area.) The alcove is 38" x 59" x 30 1/2" x 74"H. Red Guard has been suggested as has truck bed lining. Tiling the whole room also, with "curb" transferred to between bathroom floor and hall concrete floor (hall floor will remain polished concrete). I don't want a curb and I hate shower doors/enclosures.

In General questions | Asked By Genevieve Holubik | Aug 17 16
15 Answers

How can I stop in stop the infiltration of musty, humid air without tearing apart the wall of my historic home?

I live in a 100 year old house in New Jersey. Most of the time, the indoor air quality is fine, but on hot, humid summer days, especially after a rainstorm, the interior of the home is immediately overtaken by a musty, moldy --sometimes downright acrid--odor, and the humidity level jumps to about 80%. This come on very suddenly, and it vanishes just as quickly when the humidity level outside drops. I turn on my dehumidifier right away, which pulls gallons of water out of the air in several hours. This helps a bit, but is it not a real solution.

In General questions | Asked By Doug Schotland | Aug 12 16
10 Answers

Has anyone tried the Foobot Monitor?

Does anyone have experience with this indoor air quality monitor? Are there better alternatives for easily monitoring key indoor pollutants?

In General questions | Asked By Steve Knapp | Aug 8 16
12 Answers

Insulating floor joists, on stilts


In GBA Pro help | Asked By Paul Huehmer | Aug 12 16
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