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69 Answers

Unvented slanted roof with radiant cooling and NO polyurethane in 4C

We are in Everett WA, north of Seattle, right on the coast, zone 4C. I hope that our location will save us...
We have a low sloping steel, west facing roof. Double, 30 weight felt paper underneath to dampen rain noise. I presume 1/2" plywood sheathing. 2x12" rafters, 11" true depth.
We will install WarmBoard R (13/16" thick OSB with aluminum tracks) underneath the rafters for summer cooling and supplemental heating in winter.

Asked By Jan Verschuren | Mar 11 15
2 Answers

Is it wise to put a product like Drainwrap behind a layer of rigid insulation?

We are getting ready to remove the existing layers of siding from an old (100yrs. +) home that appears to have diagonal board sheathing attached to the studs.

Our intention is to blow cellulose into the stud bays, then cover the board sheathing with Drainwrap integrating the window flashing into this layer, then adding 1" rigid foam with seams taped, and finally adding 1x furring strips and either Hardi or Lp lap siding.

The project is waterfront on a coastal bay in Maryland. The windows in the home are vinyl replacements in original wood frames.

Asked By mike labesky | Apr 1 15
2 Answers

Gravel under concrete footing

I am trying to finalize several aspects of the foundation design for the high-performance house we’ll be building in central Vermont starting in May. Typical of the region, our house site, which has a 7% slope, is near the bottom of 600 foot ‘mountain’ and we expect it to be moderately wet (Buckland very fine sandy loam soil that is only “moderately well drained”).

Asked By Timothy Denny | Apr 1 15
1 Answer

Basement insulation with exterior wall waterproofing

I am a new home owner trying to answer a question that evokes different responses depending on which site I visit!! Or perhaps, I am just dumb!! Anyway here goes.

Asked By Chris Simmons | Apr 1 15
11 Answers

Deep energy retrofit — Envelope upgrade questions

We are well into the process of a deep energy retrofit for our 2,700 sq. ft. house in NYC suburbs, zone 4/5A. The house is a typical 1988 contemporary with 2x6" wood frame construction, builder grade, sloppy subs, code minimum and 25 years of neglect. Long story short, we are currently replacing the roof, windows, doors, siding and HVAC. Before we started renovations, the blower door test result of just under 11 ACH50, proved that the envelope could be improved, so that is now our focus.

Asked By Andrew Wuench | Mar 31 15
3 Answers

Replace AC with a heat pump?

I've recently inherited a house in Virginia mountains, climate zone 6, that's been used as a three-season retreat. I want to keep it open in winter. Heating is via coal-guzzling electric baseboards. Conventional AC w/ exchanger in unconditioned 3rd floor attic and flexiducts.
1) Can i replace the AC w/ newest generation heat pump like those used in mini-splits? Local HVAC folks are not familiar w/ the technology, since climate is too cold for conventional heat pumps

Asked By Jerry Knight | Apr 1 15
10 Answers

Attic insulation reality check

It's time to get my attic air sealed and re-insulated and I've committed to hiring it out since the 6/12 pitch truss attic is a horrible place that I hate to work in. I'm having trouble finding people willing to blow cellulose. Everyone around here seems to want to blow fiberglass. Is this a major issue?

The first bid I've gotten is $3.20/sf for attic floor air sealing and R-30 worth of blown fiberglass. Sane/insane?

Asked By Nathaniel G | Mar 26 15
0 Answers

BuildingGreen publishes special news stories for April 1st

Here's a link to one of BuildingGreen's special news reports for April 1st:
Judge Robs Yost of Gold Medal in WUFI Modeling.


Asked By Martin Holladay | Apr 1 15
1 Answer

Best way to find the experts in my area

What or where is the best resource to find the top green architects/designers and builders in my area?

Asked By Mary Dorcey-Mussog | Apr 1 15
3 Answers

Foam under slab details

New residential construction, Zone 4A, slab on grade with attached garage. Three questions:

1. Most builders around here pour the entire slab flat; in other words, no slope to garage door and no step up into the house. Is this an okay practice?

2. I plan to put 2 ½" of foam sheets below the slab for R-10. Is there any compelling reason to continue the foam under the garage part of the slab (there would be no thermal break, the slab would be contiguous).

3. What is the detail for continuing the foam below bearing walls that will be supported by a thickened slab?

Asked By David McNeely | Mar 31 15
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