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3 Answers

Insulating the roof deck with both closed-cell and open-cell foam?

I am consulting on a home where the HO wants to have the insulation at the roof deck. They are thinking 2” of closed cell followed by 6” of open cell.

The HO put forward this idea.

2" closed cell at the roof first to provide the vapor barrier then followed by 6" of open cell which will be enough to encapsulate the top chord of the roof truss and minimize thermal conduction.

Does anyone have any experience with this type system?

Is there any concern of the two layers of foam de-bonding from one another?

Asked By Mark Parlee | Mar 29 14
3 Answers

ERV a bad choice for a tiny house near Toronto?

I am building a 187 square foot tiny house for my family of 3 in Barrie, Ontario and have some questions about ventilation. The house is decently well insulated and airtight, with 6 ½” inches of XPS on the walls and roof, 5 ½” in the floor, and a Solitex Mento 1000 exterior membrane.

Asked By Travis Marttinen | Mar 25 14
4 Answers

Uninsulated barn with wood siding: does a radiant barrier make sense?

I have a 20x30 barn with wood siding (pine boards) and asphalt shingles over 3/4" T&G decked gambrel roof. The 2nd floor loft has a 17ft height at the ridge with zero insulation. I read your article about radiant barriers and an example of an uninsulated barn with steel siding and roof was mentioned. Would a barrier be functional toward reducing air temperature in my barn and if so, where exactly should it be installed? I would try to do this myself. Thank you.
Rob Cramer

Asked By Rob Cramer | Mar 24 14
7 Answers

Exterior insulation and cement siding over concrete block

I’m planning an extensive renovation of a 1950s cinder block home in central Florida. I’ll be taking off the roof and taking down all the interior walls, leaving a bare, uninsulated concrete block wall, with no finishes either on the inside or outside.

My current question concerns insulating the exterior walls. I’ve looked at a lot of the material on Building Science, and would like to do what they have dubbed the “500 year wall.”

Asked By Lee Meyer | Mar 21 14
1 Answer

Are we creating issues in single-family homes as we seal attic leaks and push the neutral pressure plane closer to the ground?

I just read Joe Lstiburek's article BSI-075: How Do Buildings Stack Up? and started wondering - are we creating issues in single-family homes as we seal attic leaks and push the neutral pressure plane closer to the ground?

Asked By Gary Hamer | Mar 17 14
9 Answers

I need suggestions for a high-performance dryer vent

Building a LEED Platinum house and need info on drier vents and rangehoods with make-up air

Asked By david dickson | Feb 11 14
5 Answers

Recommendations for finishing a house on island in SE Alaska?

I purchased a partially completed house on a small island 80 miles south of Juneau. The 40x30, 2.5 story house is built on pilings with 2x12 floor joist on 16" centers, 1x6 walls, 16" oc, a combination of 5/16th osb and plywood, wall sheeting, all windows and doors installed, a finished raised seam metal roof, second floor (2x12, 16"oc and stairway done, and minimal inside framing accomplished. The amount of framing in the house shell is really overdone!

Asked By Michael Parnell | Feb 28 14
6 Answers

Strapping for dense pack cellulose

Looking for recommendations on the correct strapping spacing (12" or 16") to help prevent bulging with a dense pack cellulose installation on walls. We will be using Insulweb over 8" cavities, 16" on center framing.

Asked By jessie pratt | Feb 25 14
16 Answers

Window installation — sealant offgas issues


About a month ago, i had some windows installed in my basement. They were installed on a cold day, about -5 degrees Ceclcius (20-25 Fahrenheit). The weather here has gotten unseasonably colder. The sealant used to put the windows in place was Mulco's supra expert, and seems to be dry on outside, but some areas are still soft.

Asked By cory b | Jan 7 14
2 Answers

Which minisplit to get?

I'm new to this site and have been reading a lot of info on minisplits. Could anyone tell me which size Mitsubishi FHxxNA series or Fujitsu model I should get for my house: a 24,000 sf split-level home in Zone 7. The cold weather gets to -30F or so in Dec. and Jan., so it would need to be the better heat-efficient one.

I have a Pacific Energy wood stove; here is the TECHNICAL INFORMATION for the wood stove:

Heat Output Cord Wood (BTU): 72,000 BTU
Heat Output EPA (BTU): 36,600 BTU
Efficiency: 81.6%
Emissions: 3.4 gm/hr
Firebox Size: 2.1 cu.ft.
Log Size (recommended): 18 in.

Asked By Perry Comeau | Feb 13 14
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