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!

1 Answer

Hydronic Radiant Floor Heating Under Thick Slab

Hi All,
I have a timber framed house, the sub-floor of which was built with thick 2-in pine tongue and groove boards. This subfloor is also functioning as the main floor of the house in living room area, there is nothing on top of them. These boards have tons of character and I would like to keep them as the main floor.

I am renovating the down stairs and will be converting my hydronic base board heat to radiant floor in the kitchen and bathroom where I can run the pipes over the existing subfloor (plywood in these areas not the tongue and groove pine).

In Energy efficiency and durability | Asked By Ryan Wynne | Feb 4 16
9 Answers

Capillary Break Needed?

I am about to start installing 1” of Roxul Drainboard on the exterior of my foundation and have plans to bring it up to my siding. The siding sticks out 1” and the Roxul is 1” thick, do I need to leave a gap between the Roxul and Vinyl siding or add some sort of break between them to keep the Roxul from wicking up water to the siding with the potential to hit the sheathing?


In General questions | Asked By Chris King | Feb 4 16
4 Answers

Heat pump sizing


In General questions | Asked By matthias paustian | Feb 4 16
6 Answers

Radiant Barrier House Wrap- Bug Screen at base of Air Gap?

Per the manufacture specs --- going to have a 1/2 air gap between the wall sheathing wrapped in perforated radiant barrier and the finish wall.

Looking for a durable screen to install at the base of the wall between the finish wall and the sheathing to let the air and moisture escape and no bugs to enter?

It seems Cor-a-vent has a fiber based screen that sounds like it wont last?

Any advice.

In Energy efficiency and durability | Asked By Brent Shafer | Feb 5 16
6 Answers

Excavating near a tree

Apologies if this question is beyond the scope of this forum. I'm trying to figure out how close to a tree I can excavate for a footing, without doing unacceptable damage to the tree. The attached drawing shows the basic situation. The tree is some sort of Asian elm, 40-50 feet tall, with two conjoined (inosculated?) trunks, each about 20" in diameter.

I asked an arborist about it but he was very reluctant to give an opinion. (Makes sense -- he has nothing to gain and a lot to lose by approving any kind of damage.) How do I go about figuring this out?

In General questions | Asked By Ray Sten | Feb 4 16
5 Answers

Roof underlayment

Building in zone 3,cathedral ceeling in 3rd floor bonus room,using 3.5 inches of OCF and 3.5 inches of cheaper in trusses,than using a john mansville nailbase,we will have first layer of 7/16 osb roof sheathing than put nailbase down,what kind of underlayment would you advise to go on top of nailbase and under standing seam room.

Also what is the most cost effective window flashing,zip,tyvek straight flash etc.

In Energy efficiency and durability | Asked By Quinton Bryant | Feb 2 16
4 Answers

Is there any way around putting a heat source in every bedroom?

I was speaking with an HVAC guy in my area today who reminded me that code says we have to have a heat source in every bedroom. We're planning on putting a single head ductless minisplit in our 1450 sf high performance home (to be built next year). Are there other exceptions/solutions out there, or do I just stick a Cadet heater in every bedroom and disconnect them after the inspector checks it off his list?

In Building Code Questions | Asked By Alyssa Hoyt | Feb 4 16
12 Answers

Geothermal Quote question

I am building a new home this Spring and I plan on having ground sourced geothermal. I received a quote from one contractor in my area. His plan is to do a 6 ton horizontal slinky loop field with a 4 ton heatpump. He claims that an oversized slinky loop field performs the best, however I've heard bad things about the slinky loops, and slinky is the only kind of loop they do.

It doesn't seem efficient or cost effective to overbuild the field since that is a major cost. Does anyone have experience with this?

In General questions | Asked By Jordan Garrow | Feb 3 16
2 Answers

Blown Insulation

Hello, we have a bonus room over the garage that does not have an attic. The ceiling of the bonus room is drywall, studs, then roof. The ceiling goes to an angle, then across to the other angle to create a ceiling that looks like the letter "A". I took out the middle line of the "A" and noticed the insulation had been tamped down by a previous owner's rodent problem. I am wanting to blow in insulation between the ceiling and the roof in between the studs, but I am not sure if I will have a moisture problem. Is blown in insulation the way to go?

In Building Code Questions | Asked By John Roy | Feb 4 16
3 Answers

Siding house in Maine

I am stripping and resideing my house I was looking at a product called prodex insulation it says it works as a vapor barrier as well as a high r-value what do you think of this type of product thanks

In Energy efficiency and durability | Asked By David Bernard | Feb 4 16
Register for a free account and join the conversation

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