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7 Answers

Closed cell on skip sheathing?

Please excuse the blurry photo. What it shows is 1x6 skip sheathing over 2x4 rafters. There is asphalt felt over the skip, and a snap-lock metal roof over that.

The owner (local government entity) wants to convert this attic into conditioned space, and is requesting quotes for a project that includes spraying closed cell foam under this roof deck.

In General questions | Asked By David Meiland | Feb 6 15
2 Answers

insulation over plaster and lathe

I have found this discussion on applying insulation directly to plaster walls.
http://www.greenbuildingadvisor.com/community/forum/energy-efficiency-an...

My question is, is it always safe to apply rigid expanded polystyrene directly to plaster walls, with furring strips?

The main issue I am aware of is condensation. Could it form between the foam and plaster wall?

I would apply at least 4 inches of rigid foam and 2 inches of mineral wool as a fire barrier. There is loose fill insulation between at least some of the studs.

In Energy efficiency and durability | Asked By Erich Riesenberg | Feb 6 15
4 Answers

Raised floor over slab, musty insulation problem

About a year ago I built a small apartment inside part of a detached garage. I have been noticing a strong musty smell lately. The space is built on a raised floor about 8" above the garage slab with a 6 mil vapor barrier over the slab and inside of the stem wall. I've tracked down the smell to the fiberglass batts I used to insulated the space between the slab and raised floor. I opened up part of the floor to investigate and haven't found any visible mold, water or condensation. However the insulation smells really bad.

In Green building techniques | Asked By Kevin Hardy | Feb 4 15
7 Answers

Double Stud and Sheathing Moisture, Is negative air pressure a solution?

I've been reading a bunch about moisture and sheathing, mainly when studies reference injecting air into an insulating wall and measuring the moisture increase above recommended levels. I've also read about rusting door latch mechanisms in one specific instance where the HRV was adjusted to maintain a positive pressure.

In Energy efficiency and durability | Asked By Joseph Malovich | Feb 2 15
2 Answers

what are the efficient methods to reduce CO2 levels in an office.

Sir/Madam,

My foffice is with 1193 cubic meter volume with centralised air conditioned system.. Daily 180 employees will work 8-10 hr/day. When the mornign session starts. Gradually CO2 level will increasing to 3000ppm at peak. But, recommended level should be <1000ppm. So, please give us your ideas to maintain co2 levlel below 1000ppm

with regards,
k.s.p.kumar.

In General questions | Asked By KSP KUMAR | Feb 6 15
4 Answers

Does polyiso need to be flush with CMU crawlspace wall?

When state-sponsored program came to put in vapor barrier in my crawlspace (it is 5' tall around perimeter) they used polyurethane foam to stick poly sheeting to about 15 inches up on the crawlspace CMU wall. They also sealed some cracks and gaps in that wall with foam.

Now I am ready to install vapor barrier to deal with radon. I am also going to put some recycled polysiso I got. Those panels came out of commercial building, so there is no reflective coating on them.

My two questsions:

In GBA Pro help | Asked By Apollo S | Feb 5 15
3 Answers

Where to Place Wall Insulation in Florida

Hi. I'm building a home in central Florida. I plan on attaching a continuous layer of rigid insulation on the exterior, then placing furring strips over that for siding. However now I'm second guessing. The exterior insulation would allow me to take advantage of the block's thermal mass, but now I'm wondering if the insulation will cause more heat gained to remain in the home, cooking the place. Would it be wiser in my climate zone to place the insulation on the inside of the block?

Thanks,
Trevor

In Green building techniques | Asked By Trevor Bowden | Feb 6 15
65 Answers

High humidity issues in a spray foam attic

Have an interesting one here for you building science detectives.
Existing two story home built in the 1950s – Charlotte, NC (mixed humid) – approx. 3000SF. Existing mechanicals were a furnace in the crawl space with duct work distributed throughout the house and an air conditioner in the attic serving the second floor. Old batt insulation in the ceiling, wall insulation undetermined (we think none) and batts in the floor.

In General questions | Asked By Danny Kelly | Jun 18 10
8 Answers

Order of upgrades

In an older house, is there a particular order in which air sealing and insulating upgrades should be made? I understand every situation is different, so I am looking for general guidelines. I am looking at possibly purchasing a 40 year old house and planned on trying to air seal the attic and rim joists of the crawlspace right away as well as duct sealing. Any big holes like pull-down attic stairs would also be addressed. After completing the most obvious work I'd like to have a blower door test done.

In Energy efficiency and durability | Asked By Daniel Gillen | Jan 28 15
1 Answer

Zone 2 wall insulation code

Was reviewing the IRC for insulation requirements for zone 2. Wood frame walls at 13 and mass walls with exterior foam at 4. Why the difference? And this brings up the real question which is: I'm about to put rigid foam on the exterior of a single story block house......any idea what the r value I should shoot for before reaching the point of diminishing returns?

In GBA Pro help | Asked By Robert Brown | Feb 5 15
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