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14 Answers

Two backdrafting appliances and dust — Do I need an HRV?

Hello, I have a problem with my house.

1) My house is probably air-tight

2) My water heater backdrafts whenever the bathroom fan is on. It's probably backdrafted every single morning (windows fog up & I feel the warm air at the flue when it kicks on....it only stops once turning off the bathroom fan).

3) Opening specific windows in the basement relieve the backdrafting of the water heater.

4) There was a lot of dust on a return-air duct that was right above the water heater. Another supply duct near the water heater had rust.

Asked By J Pritzen | Nov 26 15
0 Answers

Questions about insulating 1947 concrete block home in Florida

We purchased a house in Orlando that we plan using as a rental. It is a one story block home, about 850 square feet. As with most houses built here during that time period it had no insulation with the exception of some blown in cellulose in the attic. We have gutted the house and found that originally there was no furring strips and drywall on the inside of the exterior walls, they have been painted and wall papered a couple of times then someone furred them out and put up wood paneling.

Asked By Nathan Vaughn | Nov 29 15
0 Answers

Adding foam board to ceiling rafters?


The rafters in my ceiling are only 2 x 6. Is it acceptable to lay polyiso sheets across the top of the rafters, or should I be concerned about the foam acting as a second vapor barrier? The fiberglass batts have a kraft liner facing the sheet rock.

If the answer to the above is yes, can I place the foam in between the rafters against the sheet rock under the fiberglass batts?


Asked By Donald Mendell | Nov 29 15
0 Answers

Source for Rock Wool batts in Albany NY area

I am interested in using Roxul or other rock wool peoduct in bith batt form and board form for my build in Saratoga County NY, near Albany. Is there anyone here that can recommend either or both a source and an installer in this area?

Asked By Joe Suhrada | Nov 29 15
5 Answers

SIP walls insulating the floor joists

I'm attaching a picture posted by Insulspan, the SIP manufacturer we're getting a quote from. It shows the SIP wall on the edge of the basement wall with the floor joists on the inside edge, providing continuous insulation of the rim joist. Has anyone seen this done? I thought at least 4 inches of the floor joist had to rest on the basement wall to be structurally sound. I plan on using superior walls which are 10.25 in thick and 8.25 in SIPs.

Asked By Brian W | Nov 28 15
1 Answer

Pros and cons of Grace Ice and Water compared to Tyvek Drainwrap

If applying a WRB under rigid foam insulation, what are the pros and cons of using Grace Ice and Water Shield compared to Tyvek Drainwrap, in terms of protecting the sheathing, serving as an air barrier, difficulty of installation, flashing details, and any other reason you might prefer one product over the other to serve as a WRB? Assuming that the Grace product is more expensive, do you believe that it is worth the additional cost on a 2,000 square foot home in Zone 5?

As always, any advice or opinions are greatly appreciated.

Asked By James Timmerberg | Nov 29 15
4 Answers

Insulating a non vented vaulted ceiling in Canada


I've recently had a 10x14 foot backyard studio built for me by a local company. I asked them not to insulate it because I was hoping to save some money by doing it myself. However, after some research I'm not really sure how to continue.

The studio has a vaulted 2x6 ceiling (with one skylight) with no ventilation. The soffits also have no vents. Initially, I was planning to just shove some fibreglass batts up there, putt up a vapor barrier and then finish it off with some wood paneling. However, after researching it sounds like that's a recipe for moisture and mold.

Asked By Kirsten Quist | Nov 28 15
1 Answer

Where to put Smart Vapor Retarder?

We are remodeling the second floor of our 1956 Cape in Williamsburg VA, climate zone 4. I need advice about where to incorporate the MemBrain smart vapor retarder in the roof and wall insulation stack up.

Roof stackup: Asphalt shingles- Durabuild synthetic underlayment-1x8 plank roof decking- approximately 1.5 inch airspace (ProVent running soffit to ridge vet)- 3.5 inches of Roxul R15 between the 2x6 rafters- 5.5 inches of Roxul R23 between 2x6 “mooney wall” furring running perpendicular to the rafters- sheetrock.

Asked By Chris Kolloff | Nov 29 15
2 Answers

To vent or not to vent?

First, I apologize for a question asked many times on here. After just asking about access to an unvented attic, I started to question the whole unvented idea. I live in zone 3, plan to use Zip R (R-6.6) with cellulose inside 2x6 walls.

I originally planned on unvented with 5 inch nailbase with around 3 inches of OC spray foam in the bottom of roof.

I've read every article I can find on the subject on here and other sites. If my ducts and air handler will not be in the attic, would it be better to go unvented? I know with unvented you gain a lot of volume of air to condition.

Asked By Eric | Nov 28 15
0 Answers

detail on garage wall abutment to exterior block wall

Hi there - been using this site for about a year. Just performed an energy retrofit where I ripped out the ceiling in the garage Redid the ducting system, fixed a lot of electrical that was wired incorrectly or unsafe, airsealed, put ithen put in two layers of 1/2" polyisocyanurate, covered with 1/2" drywall.

If you follow this link: http://www.greenbuildingadvisor.com/cad/detail/air-barrier-garage-band-j...

that is exactly the configuration i built to (I did not use furring strips like the detail calls out though).

Asked By daniel slaman | Nov 29 15
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