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

[Click map to enlarge]

drawing of climate zone map.gif

Advice can depend on climate -- Please specify in your question.

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!

Ask a Question >
2 Answers
Building on bedrock with 2/12 slope

I want to build a workshop on granite bedrock with a slope of 2" per foot. Shop will be 20' wide by 28' long. I want the shop to have a wood floor (to save wear and tear on feet and knees). I was thinking of 1' by 8" by 28' concrete footing on high side stepping it down over 20' to an 18" by 8" by 28' footing on the low side. I will use pressure-treated 2"by 6" to fill in stepped footing to bring up to level for floor. Floor will be 2"by 8" joists supported by beam running at 10' on center. I want the floor to be well insulated. I live in a 6a climate zone.

In Energy efficiency and durability | Asked By mike maclean | May 26 10
10 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.

In Green building techniques | Asked By Kurt Samson | May 19 10
6 Answers
Open-web trusses for walls and roofs

Anyone out there have experience of using open-web joist trusses as studs, rafters or both? I know Katrin Klingenberg has used TJI joists as studs but I was intersted in something with a more open structure and no, or little, OSB. It's really to save the time in making my own Larsen trusses on-site.

In Green building techniques | Asked By Interested Onlooker | May 25 10
40 Answers
Higher solar heating fractions???

I find it hard to believe that with today's building and insulating technologies, that most or even all of a home's space and hot water heating can not be provided by solar... I realize that the issues of heat storage and controlling the release of this heat need to be dealt with. I am intrigued by Robert Starr's (www.radiantsolar.com) ideas for an insulated earth bed storage system. Read the DOE's report on this system...they seem to be rather enthusiastic. (note that it was done in the 80's).

In Mechanicals | Asked By Garth Sproule | Sep 28 09
5 Answers
Locking two buildings together; old, and new build

Full circle? We are looking, again, at adding on instead of building new. I'd appreciate any links to prior discussions on this issue, here or other sites, books, etc. PROBLEM: How do you lock a new and an old foundation/footer together? Presently, we have a 2-story, daylight basement, stick. We are considering adding two stories on the daylight end, essentially just expanding horizontally. This will get everything my wife wants on one floor and leave a huge dungeon for me.

In Mechanicals | Asked By John Klingel | May 21 10
1 Answer
What should I do to help overall energy efficiency to an old building?

I am working with a 2-story commercial building with a restaurant being operated on the main floor and a large unused/un-finished upper level. The windows on the upper level have been replaced recently. There is insulation covering about 25% of the floor area on the upper level. What can be done on the upper level to achieve greater energy efficiency in the building overall?

In Energy efficiency and durability | Asked By Greg Nissen | May 24 10
13 Answers
Windows and low-e coating

I have always understood that low-e windows worked in cold climates when you had the low-e on the exterior side of the pane closest to the interior (surface 3) and vv for hot climates (surface 2). This is stated pretty clearly in the book Residential Energy, for example, which most energy auditors use to train from, and I just checked with the DOE website and they say the same thing.

In GBA Pro help | Asked By Amanda Evans | Oct 25 09
2 Answers
New Office Remodel = poorly insulated??

A year and a half ago, I purchased a 35 y.o. building, gutted and remodeled the entire structure for a new professional office (dental). The original walls, sub-floors, foundation and half the roof were retained. Everything else was built new: insulation, electrical, mechanical, water/sewer, etc.

In General questions | Asked By Geoff Sheen | May 23 10
20 Answers
Thermal bridging with spray foam insulation

If you have 2x12 rafters and are installing approximately 5 inches of foam do you need to encase the rafters in foam to prevent heat loss through the top of the 1 1/2" of rafter? Or is the heat loss so insignificant that totally encasing the rafter in foam would prove to be unnecessary?

Gary

In Energy efficiency and durability | Asked By gary | May 4 10
4 Answers
To Vent or Not to Vent?

I will be building a new home in Vermont this summer and I was planning on installing a vented cathedral ceiling and insulating it with dense pack cellulose. I recently spoke with an insulation sub-contractor and he explained to me that if the R-value is above 60, then there is no need to vent the roof. In fact, his company guarantees my roof performance. I was under the impression that venting was the only way to go. Which method is better?

In Energy efficiency and durability | Asked By Graham Mink | May 21 10
Register for a free account and join the conversation


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