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

Q & A Instructions

[Click map to enlarge]

The GBAGreenBuildingAdvisor.com web site has a wealth of articles on a wide variety of construction topics. Before posting your question, you may want to check out the articles on this page: How To Do Everything. You just might discover an article there that provides the information you seek.

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

If you want to post a question, 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!

4 Answers

New Mitsubishi Hyper Heat multi splits have finally arrived

I was having a discussion with someone on reddit and they mentioned having a MXZ-3C24NAHZ model recommended by a contractor, which I had never seen before. Googled it and, lo and behold, I find documents published just a couple months ago (like this one) describing a whole new line of Hyper Heat multi splits, sized from 20,000 BTU/hr through 48,000, and supporting 2 to 8 indoor units. HSPF rating is generally in the 9 to 11 range.

In Mechanicals | Asked By Nick Welch | Jan 13 15
10 Answers

Airspace for solar barrier

I am adding a solar barrier between layers of an alluminum roof. The existing roof is over a covered florida room. The roof system has a lower layer that is also the ceiling. The lower layer is connected to the top layer by 3 inch alumuinum I beams. The roof is insulated with porous styromfoam which is noisy when it rains and does not stop any heat penetration at all. Impossible to aircondition! I purchased a solar barrier to place between the layers of room.

In General questions | Asked By Phillip Ragan | Mar 4 15
2 Answers

How can I super insulate, air seal, and vent this space?

This is the top floor of my new to me house in zone 5. Under which is a fully insulated living space of 12 years. So right under that decking is standard 10 in fiberglass..

In Green building techniques | Asked By stephen edge | Mar 5 15
3 Answers

New home questions

I plan on retiring to BC in a few years and building " a pretty good home" . I have been reading almost everything on the GBA web site, very informative. Really appreciate all the blogs by Martin and all the others .

In Energy efficiency and durability | Asked By bert matter | Mar 4 15
11 Answers

Plans Review with a few questions

We are getting closer to building our new home. The preliminary drawings have been completed (links to plans at the bottom). We aren’t exactly building a green house, but over the last year I’ve read an enormous amount of good information from this website and a few others to help guide me in building a more durable and energy efficient house than what is typically done around here (vented crawlspaces and ducts in a vented attic are pretty standard here).

In Plans Review | Asked By Michael Geoghegan | Feb 4 15
2 Answers

Why not skip the sheathing?

I am just a layperson who wants to build a pretty good home and have been considering two wall types, but as I'm reading, I feel like I’m missing something regarding the sheathing.

In General questions | Asked By Jonathan deHart | Mar 4 15
2 Answers

Remote cabin exterior wall design

Questions on remote cabin exterior wall design. I am building a small cabin, off grid in a remote location - Yukon Canada (cold dry climate). Not for full time habitation, but I suppose that could change in my future or with a with a different owner. Wood heat only, small solar to run LED lights, 12v stereo, no running water. Dimensions 16' x 24' (2 stories). I would like to minimize the exterior wall thickness as the interior space is not especially large to begin with. Cost and ease of construction are major planning considerations.

In Green building techniques | Asked By J. Bishop | Mar 4 15
5 Answers

Will adding rigid foam insulation to the inside and outside of my d-log house cause mold?

I am planning to add rigid foam insulation to the outside of my old leaky d-log house and adding douglas fir slab siding with chink. My electrician would like for us to fir out the inside to avoid having to router out chases for new wiring. If I add foam insulation (open or cloased cell) to the inside will I risk mold on the logs? The house is located in the upper Arkansas valley in central Colorado, zone 6 I believe.

In Energy efficiency and durability | Asked By Judith Blythe | Mar 3 15
1 Answer

Will a smart vapor retarder offer enough moisture protection to be used for bathroom walls?

We're planning to use MemBrain for an interior vapor retarder throughout our two story house currently under construction. The wall assembly is designed to dry to the interior. We want to limit moisture diffusion into the walls for the short duration of high humidity during showers while allowing walls to dry if sheathing accumulates moisture during heating season.

In Energy efficiency and durability | Asked By Dave Brooks | Mar 4 15
1 Answer

Connecting ICF Foundation Wall + Timber Frame / SIP?

I'm planning to build a timber frame home soon (eastern white pine and SIPs) and have received a decent quote for an ICF basement.

I like the idea of efficiency in this combination and know that others have built this way but am a bit confused about how they connect? We are responsible for the foundation and first floor decking before the timbers arrive.

Does any one have construction details they could share for this (ICF wall, sill plate, first floor deck, post, blocking, and SIP positioning)? If not can any of you share your experiences with this?

In GBA Pro help | Asked By Jeremy Mayhew | Mar 3 15
Register for a free account and join the conversation

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