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4 Answers

DER Envelope upgrade questions

We are well into the process of a deep energy retrofit for our 2700sqft 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 11ACH50, proved that the envelope could be improved so that is now our focus.

Asked By Andrew Wuench | Mar 31 15
66 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

With taped exterior sheathing, is there any benefit to caulking each stud bay?

I have 1/2 cdx sheathing taped with zip tape. I takes the sheathing to all window rough openings as well. I was planning on caulking or applying acoustic sealant to the crack between the sill plate and the bottom of the sheathing and again at the top plates. The sheathing was not glued or gasketed at these joints.

Since all of the other sheathing joints are securely nailed to blocking and taped with ZIP tape I presume there is no point to caulking the stud bays?

Asked By Rick Van Handel | Mar 31 15
1 Answer

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
0 Answers

More wet fiberglass

Some of y'all might remember this picture...
and the discussion that went around it, concerning careful backoff
[from the wall] and sealing-up of the outer duct sheath to make sure
no water infiltrated into the fiberglass between. This was for the
intake duct on my HRV setup, the coldest part, and after retrofitting
same on my HRV setup accordingly it was fine all this winter.

So I was downstairs putting the snow shovels away [wishful thinking?]
and happened to bump the end of the *exhaust* side duct, which

Asked By Hobbit _ | Mar 31 15
0 Answers

Reasons NOT to use Fibertec Windows for your Home

When I started window vendor selection for my new home build, I was concerned about the customer service and issues meeting delivery deadlines I had read about. I was reassured by the Sales Director that these were "issues of the past" given changes that had been made in the company recently. As I would learn, this is the furthest from the truth.

Asked By Darin Anderson | Mar 31 15
14 Answers

Alternate cathedral ceiling retrofit

I have a project related to a thread titled "How can I best retrofit and insulate an existing cathedral ceiling?" In my case, the zone 4b semi-arid west texas 1978 home's cathedral area has low density glass batts (or none) along with 1x10 or 12 deck boards over 2x12 rafters. The shingles above this unvented space have some blistering, and I was going to replace them along with resetting two skylight curbs that are incorrectly installed and caused some sheet rock damage from skylight leakage.

Asked By Glen Poklikuha | Mar 27 15
7 Answers

Insulating truss joists 16" on center — Best way?

Batt insulation for 24" o.c. The 2x lumber is 23" wide. The truss joists I'm looking at are 2x4 lumber 24" o.c. The space between the trusses is 21.5". Does anyone know if R-19 batts are available in 21.5 or 22"? Seems like squeezing a 23" wide batt will not work well.

Also the tiger wires used on 2x lumber will not work well on a truss. Is there another method of holding the batts up to the floor?

Asked By Walter Gayeski | Mar 25 15
23 Answers

Insulating wood I-joists with Roxul

O.K., to repeat, I'm building a 1-story house in Zone 4C. Builder is using wood I-joists 16" O.C. for the floor. After considerable thought and reading, including comments by Dana Dorsett and research by Washington State University, I decided that an open crawl space would work for me. However, I have insisted that we use good insulation: R-24 (commercial size) stone wool batts by Roxul for the floor insulation. This comes in 16.25" widths. My builder says, Fine, but how are we going to shove them past the flanges at the top of the I-joist so that they're snug against the floor?

Asked By Gordon Taylor | Nov 21 13
5 Answers

Exterior foil-faced polyiso question

I live in the San Francisco Bay Area and my application is as follows:

Plywood – sealing all plywood seams with Signa Wigluv – 2 layers of ¾” foil faced polyiso (all seams taped) – WRB – Rainscreen – Fiber cement siding:

The plywood is serving as my primary air barrier. I understand that any moisture that gets behind the first layer of polyiso (between the ployiso and plywood ) will dry to the inside and any moisture that gets on the outer layer of polyiso will dry to the outside.

My question relates to the area between the two layers of foil faced polyiso.

Asked By Randy Mason | Mar 16 15
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