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1 Answer

Calculating the pressure difference of a home WRT outside

Back in college I was shown a formula that use the temperature difference between indoors & outdoors (Fahrenheit) , and the height of the house (feet), and a fudge factor to calculate what the pressure difference would be between the home and outside (in Pascals).

I can't seem to find it. Does anyone know that formula, or the elusive fudge factor is?

Dan Phillips

Asked By rdanomly | May 30 17
0 Answers

Practice makes perfect

Construction work, as we all know, is skilled work.

Here is a link to a video showing Chinese workers transferring mortar. It's short, and it's worth watching.
Video: Transferring mortar at a job site in China


Asked By Martin Holladay | May 30 17
1 Answer

Advice for flat roof installation

We are having a new roof put on an addition that was originally built in 1919.We are in Southern California. It has to remain flat because several windows look out on to it. I am struggling to find alternatives to the asphalt my contractor wants to use. One of the main reasons I don't want to use them is the off-gassing and the windows that are right there.
Contractor didn't like idea of garden roof and I have found so many conflicting opinions about PVC roofs vs. TPO vs. EPDM.
Any help would be so appreciated.

Asked By GirlCab | May 29 17
3 Answers

Attic insulation, vapor retarder, radiant barrier: Advice needed

Hi, I live in the 4a climate zone. Looking to insulate a small (16 x 30) attic, which currently has little to no insulation and no HVAC in the attic. I'm planning to remove the existing (minimal) insulation, prior to sealing and insulating. I'd like to do this properly but I don't know what is the best way to insulate this attic? Does it need a vapor retarder? Is a radiant barrier needed? Should I use Batts, blown-in or spray foam? I think I'd prefer blown in over Batts, which raises the vapor retarder question.

Any advice would be greatly appreciated.

Asked By Neil Squires | May 28 17
3 Answers

Effect of different exterior wall insulation schemes on sound control

Hi all,

While reading the recent write-up of an exterior insulation Q&A (http://www.greenbuildingadvisor.com/blogs/dept/qa-spotlight/making-case-...), I noticed that no one mentioned any benefit impact to exterior sound transmission by increasing cavity insulation or increasing exterior insulation on transmission of exterior sound into the home. Internet CW seems to be that the density of cellulose and rockwool have positive benefits over fiberglass but beyond that, I don't see a lot of discussion.

Asked By Keith H | May 30 17
6 Answers

Dense packing cellulose with the Krendl 425

Hi All,

I am going to attempt to dense pack several horizontal stud bays (2x10 floor joists, 12in o.c., between attached garage and bonus room) using the Krendl 425 (14amp 2-stage blower, pushing 1100 – 1400 lbs of cellulose per hour) over the upcoming weekend.

Asked By Joe Duchek | May 23 17
1 Answer

Triple-pane windows for a high-efficiency cabin

1400sq. Ft. cabin...Zone 7 10,000 HDD with R40 walls and R80 in roof. Looking for ideas for windows. I'm probably looking at a manufacturer in North America for costs and timeline to get.
Have looked at H-Windows, in person and several others online, including Marvin "Tripane".

Any pluses or minuses with any of them would be helpful.


Asked By Steve Lenertz | May 29 17
8 Answers

Hot dormer: radiant barrier time?

I have read Martin's "Radiant Barriers: A Solution in Search of a Problem"

I have an existing house, about two years old. The second story is made up of two dormers, a bathroom, a "bonus room," and some "usable" attic space (outside building envelope).

The second story gets much hotter than downstairs (8-10 degrees in hot days). I'm interested in whether there's anything we can do to address that, short of cranking the hvac.

Asked By Maurice A | May 27 17
3 Answers

Should I tape vapor barrier to foam board?

Good day. I'm remodeling a tub surround on an exterior wall and want to air seal properly. Should I tape closed the "pockets" of black plastic, which I believe are the laps of vapor barrier where they come through the foam board and then down on the outside?

Tim in TX

Asked By TX Tim | May 28 17
7 Answers

Wide door for workshop built to passive house standards

I am looking for an affordable wide door for a workshop that meets passive house standards.

I want to preserve as much wall space as possible.

I am looking for at least 6 to 8 feet of opening. With this being a workshop, it doesn't need to be a work of art, just functional.

I had looked at the Zola breezeway panel door. That is not available in their lower priced uPVC lines.



Asked By Andrew Sanderson | May 28 17
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