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9 Answers

Crawl space ventilating fan

Hello, all --

I have a 625 square foot sealed crawl space that I need to ventilate. I can't seem to find a ducted fan that will suit this application. I'm no internet moron, but maybe I am tonight? What do you all use? My local building code jibes with what Martin wrote about in his article "Building an Unvented Crawl Space."

“a continuously operated mechanical exhaust ventilation at a rate equal to 1 cfm for each 50 square feet of crawl space floor area.”

In GBA Pro help | Asked By Jeff Nelson | Nov 19 13
2 Answers

Rigid foam over first floor insulated slab?

First off, thank you to everyone who participates in this forum! I have found it very useful in answering many of my questions during the pre-construction and now construction phases of my home build.

In Green building techniques | Asked By Keith Andrews | Nov 20 13
10 Answers

Relocating drains to maximize drain water heat recovery

I have a central stack for the bathroom, iron pipe, probably 4" (not a plumber and haven't measured it, but it's big). This is where my DWHR will go, and serving the shower will give me the lion's share of the heat recovery benefits. But I wonder if I could do better.

In Mechanicals | Asked By Nick Welch | Nov 15 13
6 Answers

Effectiveness of sheep's wool as a radiant barrier

In short, my question is: what is the emissivity (or reflectance) of sheep's wool insulation?

This article gives an R-value of 3.5 to 3.8 per inch for wool: http://en.wikipedia.org/wiki/Wool_insulation
This article gives an R-value of 3.7 per inch for cotton: http://en.wikipedia.org/wiki/Building_insulation_materials

In Energy efficiency and durability | Asked By Woodland Dweller | Nov 18 13
5 Answers

Any discussion groups in CT?

I'm wondering if there are any discussion groups/professional associations in the CT area?

In General questions | Asked By Benjamin Bogie | Nov 18 13
4 Answers

Insulation of concrete walls (above and below grade)


My wife and I, after a lengthy search, have finally found a house that meets our wants and needs. However, I have one potentially serious concern, and that regards how the contractor insulated at least some of the 1922 home's concrete walls in the recent to-the-studs renovation. To be clear, in addition to the basement, this home has above-grade concrete walls as well (with a stucco exterior). I'm attaching a picture to show a portion of the main floor when taken down to the studs.

In GBA Pro help | Asked By Doug Elliott | Nov 19 13
4 Answers

Is it possible to install new stud frame and window from inside instead of ripping split face stone outer wall down? What about the wall ties?

Termite damage on inside stud wall around window.

In General questions | Asked By Thomas Conley | Nov 19 13
1 Answer

I want to add insulation to the cathedral ceiling in my shop

About 20 years ago I built a workshop. It has a metal roof installed over 1X4 strips that are nailed directly to the 24" oc 2X10 rafters. I had a local insulation installer spray cellulose insulation directly against the metal roof. The insulation began to fall off almost immediately and today approximately 1/2 of it is gone. I would like to put more insulation overhead and have considered either fiberglass batts or spray foam. I have always been taught to provide an air space above fiberglass but there is not an easy way to ventilate above this cathedral ceiling type area.

In GBA Pro help | Asked By Anthony Bright | Nov 19 13
14 Answers

Using Reclaimed Fiberglass (?) Faced Polyiso

I have access to some 3.5" reclaimed polyiso that I believe has a fiberglass facing on each side of the board. At least, I think its fiberglass. The best way to describe the facing is it kind of reminds me of landscape fabric.

My intention was to use the foam as sheathing on the walls of the house I'm building. I am just down the road from Urbana, IL (Climate Zone 5A....but feeling a bit more like 4A at times).

My wall assembly (from interior to exterior) is as follows.....
- drywall
- 2x6 with mineral wool batts (R-23)
- ZIP sheathing
- 3.5" polyiso (~R-22)

In General questions | Asked By Robert Kohaus | Nov 18 13
12 Answers

A resilient double-stud wall for the West coast

After reading Martin's excellent blog and the interesting discussions that followed on the potential vulnerability of sheathing in thick walls, I wonder wether this assembly might result in a good resilient wall for the PNW climate?

- Drywall
- 2"x4" load-bearing framing insulated with batts or cellulose.
- plywood sheathing as air seal and to provide shear for seismic.
- 2" gap (insulated as above)
- 2"x4" framing (insulated as above).
- 1"x4" skip sheathing at 12" o.c.
- Rain screen strapping.
- Siding.

In Energy efficiency and durability | Asked By Malcolm Taylor | Nov 1 13
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