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2 Answers

Tyvek housewrap to cover a roof?

Can Tyvek HouseWrap (or similar) be used to temporarily cover a roof?

In General questions | Asked By Sharon Marushak | Nov 9 15
6 Answers

Below-grade insulation

I'm going to be using Roxul Comfortboard IS to build 4" (R16) on the exterior of the north wall of our home. I didn't want to use XPS (like I have in the past) because of the embedded green house gases.
I'm going to continue 2" (R8) of this below grade down to the footing.

Roxul have already confirmed that Comfortboard is okay for below grade and it is easier to source than ordering Comfortboard and Drainboard.

In Green building techniques | Asked By Mark Bartosik | Oct 22 15
2 Answers

Double stud wall with batt insulation in Toronto

Mr. Martin Holladay,

I am an Architect in Toronto. I may be involved in a small interior alterations in which part of the exterior wall needs to be reinsulated. The existing construction of the wall is aluminum side, wood sheathing and 2"x4" studs with no insulation. To bring this wall up to code I need R-24. The contractor is looking to build cheap so he wants to build a second stud wall to create double stud wall and insulate with batts only and vapour barrier. My question is will the exterior sheathing gets cold with so much insulation? Is there a chance of condensation?


In Green building techniques | Asked By Lowell Lo | Nov 9 15
4 Answers

Backup waterproofing for waterproof concrete walls

I'm considering using a crystalline waterproofing admixture* in my foundation walls. Would you install backup waterproofing for this? Small cracking is self healing, but it seems like larger cracks in the concrete could lead to waterproofing failure. I'm planning a finished basement, with interior rigid foam, so the concrete won't be readily accessible for repair. (Rochester, NY area)


In Green products and materials | Asked By John Ranson | Nov 8 15
3 Answers

Curved corner sill pan flashing


We have our sill flashing membrane spanning full width at bottom of rough opening (window sill -> interior 2x6 wall).

Some sill/jamb corners were not glued tight (curved up jamb) and there is air leakage coming through this created space.

How best to deal with this?

- Taping the leaky corner tight to inside 2x6 wall doesn't seem right, and is tricky to get a good seal at that spot (outside corner/inside corner).

In General questions | Asked By kyle lamont | Nov 8 15
5 Answers

Foundation external project done, now what...

My crazy project to partially wrap the foundation exterior in Roxul
is finished, followed up by the inevitable detailed writeup.

The TL;DR is that after evaluating the viability and building-science
soundness of the idea, I covered all of the exposed block wall and
some way into the dirt with 2" ComfortBoard. Lotta work, and some
fun problems to solve.

The question is ... other than changes in moisture profile [which
I don't really expect to be significant], what else should I be

In Green building techniques | Asked By Hobbit _ | Nov 7 15
2 Answers

+100-year-old house remodel: Flanged window installation & wall retrofit

Hello All,
I am remodeling a +100 year old house (located 2 hours south of Chicago, IL) and will be installing Andersen 200 Series Double Hung windows (6’x3’) that have vinyl nailing flanges.

Existing exterior wall construction from inside to out:
Plaster and shiplap (keyed to hold plaster) (both removed to add mineral wool insulation to stud cavity), 2x4 studs (original and new), horizontal lapped board siding, asphalt (or asbestos?) shingles, vinyl horizontal siding (removing to replace).

In General questions | Asked By Jane Campbell | Nov 7 15
3 Answers

Please advise: Polyiso exterior in mixed humid coastal climate

This site is wonderful...and I'm hoping I can get some of you to weigh in on the wall assembly we are designing for an upfit of a really old single wide trailer at the coast. I'm wondering about the polyiso and how warm humid air on the inside dries out during the winter.

##### Proposed Wall Assembly #####
Based on all our reading and research, here's what we're thinking for an exterior wall assembly.
* Interior finish: 1/4" plywood paneling, painted with non-vapor barrier paint, then

In General questions | Asked By Christy Shi Day | Nov 7 15
3 Answers

Spray foam and drainage space at sill pan cavity

Hello GBA,

The gap of the sloped sill pan and window was spray foamed to the back of window flange.

I've removed foam from some windows. Is it worth removing SPF from other windows and re-spraying with less foam.. or use backer rod/sealant for interior seal?

Or should I leave the rest like they are and have the blocked drainage gap.

I'm wondering if it is more important to insulate under window frame to improve performance of the outie windows.

In General questions | Asked By kyle lamont | Nov 7 15
6 Answers

Siga Corvum tape

hi all, i would like to trim the foam and apply corvum for additional airtightness. i got a little overzealous when flashing the window r.o.. should i cut the tyvek back to the same depth as the window so that the corvum would adhere directly to the window and osb? i realize if i do not cut the tyvek back i will be relying on the bond of the tyvek tape bonding the tyvek to the osb...

In General questions | Asked By erik olofsson | Mar 10 13
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