Community: Green building techniques

[Click map to enlarge]

Please register for a free account or sign in to ask and answer green building questions.

The usual rules of courtesy apply:
1. Be nice.
2. If you can't be nice, be polite.
3. If you can't be nice or polite — well, please be brief.

To attach a photo or illustration:
Under the box labeled "More explanation," look for the words "File attachments."
Click that, and you should be able to attach a photo.

Thanks for joining the conversation!


34 Answers

Options for high R-value above-grade walls (R-80)?

To make a long story short, my above grade exterior walls need to be at an R value of 80. This is to meet Passive House standards for a new residential house in a very demanding climate.

I am currently planning on using SIP's of some sort. But even the best of those only get me up to around R-50 though. Any thoughts on ways to get to R-80 while still being cost effective and keeping the size of the wall to a minimum?

I have found a number of options myself, but was curious if anyone else had thoughts or suggestions to meet such a high R value for a wall.

Asked By Tom Schmidt | Sep 19 14
1 Answer

Vented roof insulation

For a vacation home in a 5b zone, does it make sense to put exterior rigid insulation (1" xps) under a standing seam metal roof? This will have a vented attic with no mechanicals up there. I anticipate blow-in on the ceiling deck.

Asked By Robert Holland | Oct 16 14
10 Answers

Roxul Comfortboard - disadvantages?

I'm intending on insulating my 1950's Cape style house with exterior insulation. I've been planning on following the CCHRC's REMOTE wall assembly with an air tight membrane over the sheathing and 6" of EPS foam (2, 3" layers) then furring strips and siding.

Asked By Mark Fredericks | Oct 14 14
9 Answers

Building science options

looking for advice on options on getting into building science & green renovation ---- it seems there is still a disconnect between the building science research and the builders in the field.

Quick background on me --- I have a Chemistry degree and taught the subject for 8 years before leaving the field to be a remodeling contractor --- so I am very interested in the science behind renovating from an energy standpoint.

Asked By Jason Schatz | Oct 5 14
21 Answers

Interior vapour barrier with exterior XPS

I am in the initial stages of house design.

I am thinking of a double 2X4 wall construction with 2": of XPS on the outside to minimize thermal bridging.

My concern here is that building code here in Ontario requires a vapour barrier on the warm side wall

I suspect that the combination of XPS on the outside and 6 ml plastic on the inside will cause any water that might get into the wall cavity to stay there and not have any where to go .

Question : How do I get my wall to dissipate water in this design ?

Steve

Asked By Steve Babcock | Oct 3 14
12 Answers

Is external polyiso worth the cost?

First, let me say, that this community is fantastic. It is good to see so many people invloved and really dedicated to making building more efficient, and thus, playing a part in saving our planet and environment. I am always pleasantly surprised at how helpful everyone is, most of all, you Advisors. Thanks for the time and effort.

Asked By Kurt Samson | May 19 10
4 Answers

Sealing gap between garage floor & drywall?

Hi:

I am trying to figure out whether & how to air seal the gap between my garage floor and drywall in my 12-year old three-story townhouse in zone 2a. The gap is generally 1/2" wide, however in many places it's less. The door shown in the photos leads to the first-floor of the house.

I think caulk (any particular kind?) is the answer, but wanted to check first.

Also curious - without performing a blower door test, how "bad" do you think this gap is from an air-sealing perspective?

Thanks,
Rob

Asked By Robert Hallenbeck | Sep 20 14
12 Answers

Breaking thermal bridge between concrete porch and brick wall?

I have a concrete-floor porch that replaced an original wood-floor porch. It butts up right against the double-brick wall of the house (built in 1905). The house is uninsulated, so I am insulating the brick wall with rigid foam board. While I'm at it, I am thinking it is a good idea to saw-cut a 1" or 2" slot of the concrete floor right along the base of the brick wall (in other words, the floor-wall joint) to get rid of the thermal bridge that might exist, then to backfill the slot with rigid foam. Does this sound like it would make a significant difference to heat conductivity?

Asked By Paul Gorcey | Sep 26 14
20 Answers

How do you insulate cob or earth bag walls in the Northeast?

Hello everyone, I am brand new to this forum even though I have been spending the last three months here reading and enjoying the comments and articles.

My wife and I are looking to build a cob house / cottage. We live in western NY where winters are snowy and there is substantial moisture. After some extensive research we do not feel completely comfortable with straw bale and are leaning towards building with Cob for all the obvious reasons. 1. it will be cheap. 2. We have lots of clay. 3. It will last, no termites, fire resistant and we can be more creative etc...

Asked By Aaron B | Sep 27 14
4 Answers

Finishing concrete floor (slab on grade)

The finished first floor of our house will be the slab (8"+ monolithic) and we'll be doing the work ourselves. I'm pretty sure we're going to use EcoProCote products to prep/stain/seal the floor because we've seen good reviews and reports of people using it:
http://www.ecoprocote.com

Has anyone had experience using the EcoProCote products? Good? Bad? Alternatives?

Asked By Brian Post | Sep 29 14
Register for a free account and join the conversation


Get a free account and join the conversation!
Become a GBA PRO!