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8 Answers

Tamarack Cape vent dampers

Hello all - I'm a bit intrigued by Tamarack cape dampers - I've searched here and found a couple of threads that include some mention of these units, as possible solutions to issues in specific applications (wood stove OAK, and HVAC duct). I wonder if anyone has any experience with this style of damper in a bath fan exhaust? Apparently they've been around for @ 5 years. Rated to 160 deg F but I have no idea how they would perform under extreme cold conditions (such as what this winter has brought us). Any insights or comments are greatly appreciated. Thanks....

In General questions | Asked By Randy Toni | Mar 26 14
6 Answers

Used XPS or new EPS for outer layer of over roof insulation

I can get reclaimed 3" XPS and 4" ISO insulation locally for less than half the cost of new material. I am planning to reroof and put 4" of ISO over the roof deck then a second layer of foam above that. I am in zone 5B and need at least R-20 above the deck to control the dewpoint (quick thank you to Martin for providing a place and tools to learn about these things).

Although XPS has a high GWP this is used so should I care, or should I get new nailbase with EPS?


In Energy efficiency and durability | Asked By Eric West | Sep 5 14
4 Answers

Do fans help to dry objects when dehumidifier is running?

Project is a nonprofit archives building in Maharastra State, India. It has a double wall of thick masonry to provide a thermos effect that is effective at evening both annual and diurnal temperature fluctuation. The inner room (that holds the artifacts) has no opening but a door and egress, and is very airtight. No human needs, so no mechanical ventilation.

Humidity control remains an issue. Currently a small portable is proving almost adequate. Heating and cooling is not necessary.

In GBA Pro help | Asked By David McNeely | Sep 6 14
3 Answers

Open-cell spray foam vs. Roxul

Again I am asking insulation questions. I have a bid for a full foam compliment in my new construction home. They want to do 4" of open cell in the exterior walls trouble is my walls are 2x6 and it just doesn't make sense to leave that area open to me plus the foam performs best at 4" thick so I understand the cost difference for payback on no the extra inch is tough to justify.

R-14 in the stud bays with the r-9 outside with polyiso just seems a little short on r value to me??? Seems like I can do better.

In Energy efficiency and durability | Asked By Anthony Hughes | Sep 4 14
8 Answers

Humidity being trapped between an inside vapor barrier and OSB?

As a potential solution for concern about OSB being a vapor barrier, and all the related potential problems for humidity being trapped between the inside vapor barrier and the OSB, an architect has recommended to me to drill 1/2-inch holes every 8 inches throughout the OSB panels to allow humidity to escape to the outside, while the housewrap will prevent water from entering into the OSB.

I would like you to comment on the value of this recommendation.

Thank you in advance for your help,

Pierre Gingras

In GBA Pro help | Asked By Pierre Gingras | Sep 7 14
2 Answers

Masonry cement odor

We installed a Boral synthetic stone surround using Tolteca type s masonry cement at an interior wall fireplace renovation. After 6 months there is still an odor coming from the surround. That wet mud, almost gym sock smell that varies in intensity with weather changes. Boral says it cannot be the stone and the mason says he has no history or reports of this odor. We have had environmental testing for VOC, MVOC, swab, and mold. No issues, but smell was corroborated by them.
What can we do except rip it out?

In General questions | Asked By John Bertelsen | Sep 6 14
2 Answers

It rainin' in the cellar ...

Its not intuitive that forced outdoor fresh air venting of a damp cellar will make it rain indoors in the summer time. But it sure does. Lots of fan manufacturers willing to sell us ventilation for a wet basement. There is a perpetual summer time dew point in this cellar. RH is 85 and up; its temperature is 75.

In General questions | Asked By flitch plate | Sep 5 14
11 Answers

Doors: blowing agents and thermal bridging of multi-point locks

I've been shopping for doors, and mostly looking at foam-filled fiberglass in order to get a decent R-value. Most are polyurethane (PU) foam, and I'm guessing that they use HFC if not HCFC blowing agents. I'm not thrilled by the global warming impact of those. But it seems very difficult to find any information on what blowing agents they use.

In Green products and materials | Asked By Charlie Sullivan | Sep 4 14
6 Answers

Ants in your exterior foam?

Been working on a build over the past few years. It's a cape style home in zone 6. I've insulated the floor of the top floor and walls below for now because I can't afford to finish and heat the top floor. I have not heated the house yet. I'm seeing small winged ants crawling out of my north window in the top floor. The wall has exterior 2in foil faced tuff r polyiso taped with strapping and vinyl siding over it. I've recently sprayed the area with boric acid. Short of ripping the foam off the house, what else can I do?

In General questions | Asked By stephen edge | Sep 5 14
14 Answers

Using an "Arctic wall" design for a cathedral ceiling in Climate Zone 6

Wondering if the arctic wall design would be appropriate to use as a roof/cathedral ceiling here in CZ6 upstate NY. There is a comment about it on Martin's blog, but I didn't see any discussion : http://www.greenbuildingadvisor.com/blogs/dept/musings/how-build-insulat...

from inside out it would be:
2x4 service cavity,
1/2" CDX taped and sealed,
parallel chord trusses 12-12 pitch dense packed with cellulose,
vapor open WRB (suggestions for best product welcome),
2x4 furring,
5/8 sheathing,
asphalt shingles.

In Green building techniques | Asked By Trevor Chadwick | Sep 1 14
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