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4 Answers

Unvented cathedral ceiling — insulating from above

I am re-doing my family room roof, which is a cathedral ceiling.

Since the roof is being re-shingled, I thought it a good time to remove the sheathing and lay down some closed cell foam. I have some unopened from a previous project

Everything I've read about unvented Cathedral ceilings talk about them drying from the inside. Obviously this can't happen if I'm spray in the closed cell foam onto the dry wall ceiling from above

The ceiling is 8" from drywall to plywood

Asked By Paul Buchkowski | Jun 25 16
9 Answers

How efficient are recirculating kitchen range hoods with carbon filters at removing air pollutants from cooking?

I looked at a few of these filters for the recirculating range hoods and they didn't look all that impressive, but maybe I am looking at the wrong hoods. If passive houses are using recirculating hoods how well are the hoods actually working. Clearly there is a tradeoff for energy efficiency and range hood function. Is there any specific data on this? Are there certain types of carbon filters that work better than others? I am not talking about removing moisture or CO from gas ranges but more grease and other pollutants produced when cooking with electric ranges and ovens.

Asked By Dillon Vautrin | Dec 16 15
12 Answers

I am thinking of an unvented cathedral ceiling

Hi. I am thinking of an unvented cathedral ceiling. Living in Hazelton, BC (Zone 4A, I believe), and would like advice on my proposed insulation plan. Staring from the underside: vapour-retarding paint; sealed gypsum board; 3/4" strapping; 2" or 3" Roxul board.

I would like to achieve at least an R50.

Asked By Mike Tomlinson | Jun 24 16
2 Answers

Insulating above a garage roof

Location: Western NC, zone 4, mixed humid
Elevation 2000 ft
Roof: slope 2:12, standing seam.
Attic: formed with trusses and unvented
House roof insulation: Polyiso nailbase R15 min above the deck, netted BIBs below.

Asked By Jeremy Turner | Jun 30 16
7 Answers

How to work with a very deep truss in vaulted ceiling.

Hello dear friends, as you will see in the attached drawing I am looking at about an 8 foot run of 22" deep truss over my living roof before my ceiling flattens out to catch the height of the second story ceiling in the back of the house.

Asked By Barry Reicker | Jun 29 16
1 Answer

Vapor barrier

Am looking into building ICF homes in another country. My question is they do not generally heat and air condition their homes due to high energy cost. It is warm and humid and am not sure what, if any vapor barrier should be used in the roof area.

Asked By Thomas Webster | Jun 29 16
3 Answers

Trying to source 3/4 inch thick coroplast in Maine

Has anyone had luck in sourcing thicker coroplast sheets near Maine?
The one sign maker i contacted said his vendor will only supply full units and not single 4x8 sheets...

Asked By kevin freeman | Jun 30 16
3 Answers

woodshop super-ventilation: Any reason to air seal / insulate?

I'm building a 900 sqft woodshop outside of Portland, OR (Climate Zone 4c).

Based on Bill Pentz's research, the best way to avoid fine dust-related health problems is to ventilate all sanding/cutting tools to the outside with ~ 1000 CFM of air, which is enough flow to fully change the shop air every 7 minutes.
Recirculating air filters don't cut it for fine dust --- it has to vent outside.

Taking this airflow as a given, is there any reason to:

1) Worry about air-sealing the shop wall envelope? (There will be an open garage door or intake fan providing makeup air.)

Asked By Kevin Lynagh | Jun 30 16
32 Answers

Direct vent vs. power vent gas water heaters

A recent blower door test/audit has alerted me to the fact that my natural draft hot water heater can backdraft in worse case scenarios (range hood/clothes dryer/bath fan on). It seems to reverse back to a correct draft after a few minutes. It's only about 6 yrs old, so I hate to replace it, but not as much as I hate the idea of the back draft.

Asked By Erik Addy | Mar 8 16
13 Answers

Does anyone have experience with Zehnder ComfoFlex?

We are building a new house and in the final stages of design. The design includes an HRV and Zehnder ComfoTube looked great until I discovered that it is not UL listed. So, I'm curious if anyone can provide feedback on ComfoFlex. There isn't much on the intertubes...

Asked By Trevor Fontaine | Feb 9 16
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