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!

0 Answers

I Didn't know that!: Top Three Somatoline Cosmetic Hombre Comprar of the decade

Por eso hoy os hablamos de uno de los hits de Somatoline para combatir la grasa loca

In General questions | Asked By Houston Stubbs | Sep 5 15
2 Answers

How stupid can I be?

My firm just spent hundreds for a load calculation program that takes in fenestration, wall and roof loads, lighting and other internal gains, outdoor air for ventilation, location, exposures, etc. and now I find out I could have used 1000 square feet per ton! It even divides nice in base ten, by moving a few decimal places.

But seriously, the blog regarding a rule of thumb of t ton per 1000 square feet is the most idiotic, misleading, and oversimplifying way to create a cooling load that I have heard to date. ASHRAE gives the standard of care as computer analysis and that's what we do.

In General questions | Asked By Warren Worth | Sep 4 15
15 Answers

Water supply line routing

I'm building a house in Western Montana at 3500 ft, climate is not bad other than a couple week cold snap every year, though that may change. Had a couple of brain farts during the design in regards to water lines on exterior walls. It is a slab with radiant heat, so can't go in the floor.

The specs:
Shed roof, unvented with 4" ISO on the roof under rubber membrane.
Planning on R40 batts then drywall with very few holes other than some junction boxes for lights.

Walls are covered in 2" of ISO with 3/4 airspace behind siding.
Planning on batts or something in the R21 range.

In Mechanicals | Asked By Stan Smith | Sep 3 15
4 Answers

Cost comparision between conditioned and vented crawlspace

I am designing and will build a house for my mother which will be a ranch on a crawlspace. It will be in Vancouver, WA (near Portland, OR) and as one study showed, a vented crawlspace here isn't all that bad.
After seeing several homes whose underfloor insulation hasn't held up well over the years, (batt fiberglass tied up between TJIs), I'm thinking a condition crawl would be more durable.

In Energy efficiency and durability | Asked By Mark Walker | Sep 4 15
3 Answers

Is testing the air barrier with scented water vapor as effective as traditional fog test?


In Energy efficiency and durability | Asked By Amanda M | Sep 3 15
5 Answers

New 20+ SEER Variable Carrier heat pump w/ Greenspeed Intelligence system creating moisture & performance problems in the crawl

I had to replace 2 -13 SEER HVAC split systems in my house about 2 years ago do to some Sandy storm damage. One split system was a 90% gas furnace with a 3 ton 13 SEER AC and the other was a 2 ton 13 SEER heat pump.

In GBA Pro help | Asked By Bruce Howe | Sep 2 15
6 Answers

Ducted mini-split serving multiple floors

I am attempting to break my house design into zones such that I can use one mini-split for each zone. I am having trouble simultaneously satisfying two pieces of advice from this forum. In "Rules of Thumb for Ductless Minisplits," Martin says that one ductless head can serve a maximum of about 1100 square feet. That is based on distribution, not capacity. I realize that it is a rule of thumb that might not apply to a super-open floorplan, but if I violate that rule, I should have some justification.

In Mechanicals | Asked By Reid Baldwin | Sep 2 15
3 Answers

Bring windows from outside the USA?

I am building a new home in PA. I've been looking for windows. I reached out to all the name-brand window manufacturers in this area and Canada. I have a lot of windows. Got quotes for 2-pane windows which have run $45,000 - 65,000. The 3-pane windows quotes have run $60,000- 70,000.

I was talking to my cousin who lives overseas, in eastern Europe, in a cold part of the country. He just built a house with triple-pane windows. So I reached out there to a local manufacturer, and their quote for uPVC windows (with Rehau frames) was under $20,000.

In General questions | Asked By Boris Rubinstein | Sep 3 15
6 Answers

Penetrations in exterior foam and rainscreen

I will be installing 3 or 4" of exterior foam with a 3/4" rainscreen and installing new windows and siding. This will be my first retrofit of this type.

In Green building techniques | Asked By Brian Otten | Sep 3 15
11 Answers

How can I properly vent my tiny house roof (it has cross member framing instead of rafters)?

I have the framing almost complete on my tiny house, but I have run into a stumbling block. Framing the roof with cross members instead of traditional rafters made a lot of sense because the shorter span allowed smaller lumber for more head space and less weight, but upon further research my plan for venting is not going to work (I know - proper planning prevents poor performance). See attached picture for framing structure.

In General questions | Asked By Ryan Reed | Sep 2 15
Register for a free account and join the conversation

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