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!


2 Answers

In Md. I have a vapor barrier and I want to insulate and finish basement

What is the best way to finish the basement. I already paid for drainage system; vapor barrier is up on walls. What is the best type of installation...? Basement is framed 24' vs 16. This is so frustrating for me, my brother gave me R19 that he had left over but I don't think I can use it. Someone told me not to use paperback fiberglass near vapor barrier...Help!

Asked By blgoodw | Nov 20 17
11 Answers

Sizing a ductless minisplit for heating

Hi all,

I'm going to install a ductless heat pump. I settled on LG Art Cool Premier (HYV1 or HYV2). Now I need to figure out system size, and there is too much info.

I have 550 sf addition built in late '80s, which is a split lever open space, and is VERY cold (i've attached some photos)!

It has a large french door (8x10' glass, 3 sections), 7 windows, and 5 skylights. All are double glass.

Asked By Levab | Nov 16 17
5 Answers

Water pipes under exterior foam?

I’m in Climate Zone 2B and live in a house with slump block walls and a flat roof w/ no attic. The house was re-plumbed by the previous owner by running the water lines across the roof. With radiant losses, the roof gets cold enough to risk freezing the pipes 20-30 nights a year. Standard box store pipe wrap was not sufficient to keep the pipes from freezing.

Asked By Nick Van Kleeck | Nov 6 17
11 Answers

Metal roof on purlins and heating

Hi

I had a metal roof guy tell me my roof won't pass code and will have water issues. (I don't believe him, so though I would ask the experts) The plans passed and I got a building permit.

Its a detached garage ( so not that worried anyway) the roof is a engineered truss 6/12 48" O.C. with 2x4 purlins laid flat 24" O.C.
The plan was to have metal roof screwed to purlins, sofffit to ridge venting. ( not sure if I need this)
Then blow in cellulose insulation. over the 1x4 strapping holding up the drywall. Heat below.

Asked By Dave B | Nov 15 17
6 Answers

Rigid foam: glue vs. fasteners

I'll be installing 2 inch Thermax to the inside of my poured concrete foundation. I don't yet own a hammer drill, but I'm looking for advise on the best way to attach this material to the wall. I've read about glue only, plastic fasteners, metal fasteners, and strapping. Which are the easiest to install and will last the life of the house?

Asked By Andrew G | Oct 31 17
1 Answer

Regarding Panasonic humidity/motion sensing fans

As the panasonic literature states - the options for controlling their humidity / motion sensing fans is : Motion on/Motion off - Motion on/Humidity off - Humidity on/Humidity off with a selectable timer.
I think this ties the two operations together on the same timer - Meaning, if you set the timer to 30 minutes, the fan stays on for 30 minutes after motion is no longer detected or a level of humidity is reached, etc.
This seems limiting and a waste of energy if the fan stays on for more time than needed.

Asked By Nedjinski | Nov 19 17
3 Answers

Air return issue: What is best approach to diagnose why I am not getting good return flow?

House is about 3200 SQ ft. two story with a single air handler in the basement..
- (original contractor no longer living to question)
- air temp balance is hard to maintain both in summer and winter.
- Had two local companies visit wanting to add a second unit vs diagnosing existing return air paths.

Asked By BlueMTN | Nov 19 17
8 Answers

Roof membrane and live vegetative roof

Hey all,

So after Material quotes and city grants etc, it looks like its going to be viable go me to do a live vegatative roof (green roof) on the flat roof I've recently built.

now I'm thinking about what roofing membrane to put on, to go under the green roof. I am considering things like cost, longevity, ease of install, potential for leaks etc.

I'm in climate zone 6. My potential roof assembly is as follows:

9.5" I joists with R31 rockwool batting
3/4 plywood decking
6" polyiso at R34
1/2" roofboard
Roofing membrane ***
3" green roof assembly

Asked By Jamie B | Nov 18 17
8 Answers

Insulating a pole barn question(s)

I have a 24’x34’ pole barn that I want to insulate so I can add some intermittent heat while working out there. I live in Iowa. In the winter, we park our cars in the front and my wood shop is in the back. There is a ridge vent along the entire ridge (34’). No soffit vents or gable vents. I do not want to add a ceiling. This isn’t our forever home and only need it insulated enough to trap some heat in while working out there - maybe 3-4 times per month, for a couple hours at a time, during the winter months. I can’t justify the cost of spray foam (So please no advice on spray foam).

Asked By Doug Kremer | Nov 15 17
4 Answers

I want to build a wall in front of a masonry wall that emits moisture.

Dear GBA folks,

This fieldstone carriage house, built in 1910, has 22" thick stone walls (see picture). Inside on the second floor, 2x4 stud walls built about 2" away from the stone are covered with 1" plaster.

Asked By Robert Cramer | Nov 13 17
Register for a free account and join the conversation


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