Q&A: A Forum for Green Building Experts and Beginners

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2 Answers

Getting ready to build my own home. Looking at a wall assembly of 2" exterior EPS, plywood, 2x6 exterior wall with r22 fibreglass batts, 6 mil poly vapour barrier, 2x4 interior with r14 fiber glass batts and 1/2" drywall. I maintain r30 to the exterior side of the vapour barrier and r14 on the interior side so the 2/3 - 1/3 rule is maintained. I will not have to be concerned with electrical box and plumbing penetrations through the vapour except for items venting or take air from exterior.

In Energy efficiency and durability | Asked By Sheldon Lee | Aug 24 14
4 Answers

Hi All, I've been reading through the forums for the last month or so as I'm preparing to reinsulate my cathedral ceiling in my master bedroom and home office. I've found tons of great information so far and just had a few questions on my current plan to see if I'm on the right track.

In Energy efficiency and durability | Asked By Edward Dziarcak | Aug 22 14
17 Answers

Hi,
I need some advice...preferably before I cut a bunch of holes in the walls or ceiling and find out that this was a pointless venture.

So the details:

900sq foot one level, mostly open plan, highly insulated and sealed home.
Heating climate...like really... a lot. -40 C is not unheard of for stretches of time. More typical is -20 C

The house is powered completely with PV.

Heat is supplied by radiant slab, a bit of passive solar. I am also putting in a small wood stove in the next few days.

In GBA Pro help | Asked By keith ahlstrom | Aug 21 14
12 Answers

We are to build a Passive House in PA, and have "borrowed" a technique from another PH in Virginia, where part of a typical EPS under slab was substituted with a layer of perlite bags placed over just 4'' of EPS. I believe it also allowed us to reduce the slab thickness to 4'' (in the center).

In General questions | Asked By Lucyna de Barbaro | Aug 22 14
38 Answers

I had R60 blown into my 1000sqft attic where there was previously only about R11. Baffles were installed in almost every roof rafter. Air sealing of attic floor was performed. This is a low pitch asphalt shingled hip roof over the whole house.

In General questions | Asked By Jeff Watson | Jul 12 14
11 Answers

I have been thinking about the benefit of putting XPS/EPS foam under the basement slab, and it has gotten me thinking.

I am building in zone 6, where it is quite hot for a couple of months in the summer, getting up into the 90s, and cold in the winter, getting down to the 10's (Fahrenheit) on and off for a couple of months.

In Green building techniques | Asked By Stephen Youngquist | Aug 21 14
26 Answers

I am ready to insulate a new home, and need to make a final decision. I need help.
I have been the recipient of many helpful tips and guidance from thes pages as well as other green forums and it's all kind of coming to a head in our new home build as I attempt to make a decision about the insulation we will use. Here is the specs on my houses wall stack up

LOCATION: 47460 On the line of upper climate zone 4 and lower 5

2x6 exterior walls, 1/2 inch sheathing with tyvek, 1.5" polyiso foam with taped seams, vinyl siding

In Energy efficiency and durability | Asked By Anthony Hughes | Aug 8 14
2 Answers

Hello, I would like advice on insulating my garage. It has cinderblock walls and an unvented hip roof with no ridge or soffit. Rafters and sheathing are exposed and the outside is metal panels. I can't really alter the outside appearance of the home due to my local historic society (home built in 1842). My question is, can I glue/screw rigid foam board directly to the underside of the roof sheathing, in between rafter bays, then finish by screwing plywood or drywall directly to the foam board. Is there risk of moisture build up (between foam board and sheathing) if I do this?

In General questions | Asked By Dan McGonigle | Aug 22 14
19 Answers

So, My AC system died last spring, and I was prepping to put new windows (impact resistant, low e) in my house... My house is approx 2200 sq.ft in Florida, south of Tampa... Zone 2A

I had a 4 ton system, and knew that would be too big as a replacement, but my HVAC tech replaced it with what was here and said he could tune it... Now my house averages 55%rh or higher... Up into mid 66-67...

In Mechanicals | Asked By Chris Marriner | Aug 18 14
2 Answers

Question about sealing up a crawlspace with foam.

Our house at some point had an addition on the front put on. It is more like a bump out that is 6' x 16'. They did dig for a foundation and built a cinder block wall to hold this up. There is a dirt floor in the crawlspace that is above the level of the dirt outside the block wall. This crawl space is only 18" deep stays dry and only accessible through an old basement window well window that they built this in front of. Needless to say I never went in there.

In General questions | Asked By William Heiden | Aug 22 14
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