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29 Answers

Ice damming — Low-slope roof — Resolvable or hopeless?


I own an older home in Ontario Canada that may have been built between the 1920s to 1950s. It originally had knob & tube wiring.

Each winter I have to deal with ice damming along 2 sides of the roof, no where else. The areas in question are a Low-Slope roof (3/12 pitch, east & west side of the ridge) and a Cathedral style roof (8/12 pitch -- inside the home there is a sloping ceiling that is covered by drywall). See a photo of the home:

Asked By Jake Rabe | Aug 19 16
3 Answers

New roof cost? Upgrading from a low slope to a steep slope

I live in Ontario Canada. Im considering all my options to improve my old home's attic space. You see, we get lots of ice damming each winter. The existing roof has a 3/12 pitch along with an 8/12 cathedral. Im wondering if it is cheaper to have a contractor build a new steeper pitch roof over my existing (or remove the existing for the steeper one).

Asked By Jake Rabe | Aug 21 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.

Asked By Tim Lange | May 16 16
12 Answers

Insulating floor joists, on stilts


Asked By Paul Huehmer | Aug 12 16
1 Answer

Spray foam my ridge vents and soffits closed?

Okay so I am investigating spray foam insulation for my garage. The most recent company I spoke with gave me a quote but also asked if I had a ridge vent. I said yes. They said they would also spray the vent closed because spray foam creates another atmosphere and we would not need it. Another atmosphere??

I don't understand why you would want to get rid of the ridge vent. Can someone shed some light on this topic, I am in the dark.

Asked By Joe Overhaulin | Aug 17 16
3 Answers

"Flash and batt" question: can I re-use existing batts?

We had a tree fall on our house and damage a section of roof that includes a cathedral ceiling/roof. It was previously insulated with R30 batts (faced) under the rafters followed by drywall (this is in part of our bedroom). We are planning to spray 3" of closed cell foam under the rafters and fill the remaining 6.5" with fiberglass batts. I realize that the R30 batts are designed to fill an 8-9" rafter depth but was wondering if re-using them would significantly compromise their insulation properties vs using new R-19 batts.

Asked By Rob Moore | Aug 17 16
2 Answers

Cardboard insulation baffles have fallen down

Hi Pro Team!

I live in a solar (PV and HW), energy star house, built in 2005, in Washington, DC.

I was in the attic today and noticed that some of my cardboard insulation baffles had fallen over. I'd estimate about 1/3 of them. I don't go into the attic frequently, so they could have fallen over up to a few years ago.

Does this pose a problem?

Any guess on cause? Wind gusts blowing through the soffits knocking them over? Age (cardboard becoming less rigid)?

Thank you!

Asked By Michael Harris | Aug 14 16
4 Answers

Fascia/soffit at held down gable

I'm trying to figure out how to frame the subfascia and soffit returns on a roof with the gable trusses held down 5.5". I don't want to do a wide fascia across the whole building, so right now I am planning a boxed return that steps up at the inside edges of the gable trusses, but I'm not completely sold on this solution. Does anyone have an explanation or images of how you have handled or would handle this detail? I am open to all suggestions. Thanks!

Asked By Jim Tyler | Aug 12 16
3 Answers

Can you use open-cell foam against OSB and provide a 3" air gap behind it?

Building a new construction home in a Mixed humid KY climate. Question is referring to insulating the attic space of a 4/12 pitch roof system with a standard roofline. Is it a good idea, logical or crazy to try to insulate the roofline of our 4/12 roof instead of the back of drywall ceiling deck. Plan is to form a 3" air shute from the vented eave between the 2ft on center rafter trusses all the way to the vented ridge using 7/16 osb or stapled in place insulwebbing fabric, applying 6" of open cell directly against the osb/insulwebbing fabric following the roofline.

Asked By Cody Sturgill | Aug 12 16
1 Answer

Rigid Foam on Flat Roof that Terminates to Mansard

I have a flat / Mansard roof. There is an addition to the back of the house that is the same roof type as the original two roof levels. The add-on roof is leaking. It has 3 leaking skylights that I plan to remove. The sheathing is very spongy. I plan to replace the sheathing and to use 3 layers of 2.5 inch polyiso rigid foam above the sheathing.
I only plan to work on the add-on roof for now. My plan is as follows:
1) remove / replace all old decking and any structural members that are rotten

Asked By KALETA HILLIER | Aug 12 16
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