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3 Answers

Vapor barrier for garage roof without drywall?

I recently purchased a house that has an attached unconditioned garage with an uninsulated roof. The garage gets 15 to 20F hotter than the exterior temperature in the summer. Also the roof originally had skip sheathing, and plywood was added over that when the roof was redone at some point. Tar paper was left between the skip sheathing and plywood, so that is currently exposed to the garage interior. The garage stinks of tar in the summer when the roof heats up. I'm located in Portland Oregon Zone 4c

Asked By Peter274 | May 2 18
6 Answers

Has anyone used Airfoil electrical boxes in Ontario, Canada?

Will they meet code?

Asked By User-7049195 | Apr 25 18
2 Answers

Is Rmax Thermasheath-XP an acceptable alternative to Dow Thermax?

I intended on using Dow Thermax for an exposed basement application in a residential setting.

I thought there were no alternatives without using an ignition barrier (drywall) but recently came across Rmax Thermasheath-XP. For my purposes, I believe this would be a more affordable option.

Does anyone have any experience with this product? It seems to have similar properties to Dow Thermax. Does Dow Thermax have any documented advantages?


Asked By NatePa | Apr 19 18
3 Answers

Roof/Ceiling R-Value Requirement

I'm trying to understand what level of insulation is required in my roof/ceiling based on the 2012 energy code for Zone 5. Based on the tables I've looked at, R-49 looks like the basic requirement, but I'm trying to figure out if I can step down to R-38 or even R-30 based on what I plan on doing? Here's a few of the details:
- I will have no attic (100% vaulted ceiling)
- There will be no cavity insulation between the rafters. All insulation will sit on the structural roof deck and be continuous.

Asked By rodrob15 | Apr 19 18
6 Answers

Basement vapour barrier


Asked By Paul Job | Feb 17 18
0 Answers

Replacing traditional masonry chimney with metal chimney pipe

Hi all,

I live in 1950s ranch in Chicago. We've invested a lot into improving the efficiency of the home: 95% eff radiant heat, indirect DHW, minisplit for AC, lots of airsealing and the new low carbon CC sprayfoam at our roofdeck. We are now looking to replace our roof (keeping asphalt). We've hired a roofer but he won't start until we rebuild the chimney. The brick is crumbling from when the mechanicals used to pump moisture through it (they no longer do).

Asked By Brian Gray | Mar 18 18
3 Answers

Attaching Porch Ledger to House

I'm currently in the design phase of a modern cabin. I will have a porch roof that extends about 12 feet out and covers a deck. The problem is I don't have a rim/band joist to attach to (the porch ledger will be located about 11 feet up on a 14 foot wall). So I'm wondering what the best practice is in this situation. It seems like attaching to studs won't do the job. Can I just install 2x10 interior blocking between my studs to attach to?

Asked By rodrob15 | Mar 11 18
10 Answers

Can you spray closed-cell insulation over mineral wool insulation?

New house design with 2x4 outer wall with mineral wool then 1 inch gap then 2x3 inner wall. gap and 1 inch of inner wall sprayed with closed cell

Asked By Joseph Isherwood | Feb 26 18
4 Answers

Indoor air intake into high-efficiency tankless water heater

I have the option to let our new tankless water heater intake indoor air (it will be installed in a semi-finished basement), or intake it from the outside. The manufacturer seems to be OK with either approach.

What code would/does apply in this case?

PS. Our furnace/boiler intakes indoor air as currently installed, so logic tells me I could do the same with the tankless water too!?

Asked By Rocketscientist51 | Mar 2 18
2 Answers

Can the granular fill used for soil gas mitigation be compacted or is it self-compacting?

In order to maintain a complete thermal break I want to place 1 1/2" of xps under my slab. The 5" slab acts as footings for interior bearing walls ( floor load only). The XPS easily exceeds the required compressive strength (even for foundation footings) but normally fill under any footing has to be compacted. I suspect that the granular fill (less than 10% fines) is considered self compacting. If compacting is required it could compromise the permeability? Alternatively I could place concrete footings below the foam layer but that would be a lot of work and expense if not required!

Asked By Dave@terrace | Feb 26 18
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