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!

17 Answers

Mitigating high indoor humidity

I've been battling indoor humidity issues for some time now and need more advice.

Here are some quick stats:

--Location: Western Washington

--1600 sq ft one story rambler built in 1987

--Two adult occupants and two indoor cats

--Main heating is supplied by a free standing propane stove that vents to the outside. Supplemental cadet wall heaters

In General questions | Asked By Travis Canfield | Oct 18 16
3 Answers

What's the best all around roofing/insulation solution for Zone 5?

Hello to the community. I am in northern Nevada zone 5. This is an arid valley with normally low humidity but it can get some really high winds... upwards of 80 mph. The house I just bought was built in the 70's. There is about 6 inches of blown insulation in the attic but none under the roof sheathing. I do plan on bringing the attic insulation up to at least R40. The attic has two small gable vents but zero soffit vents. The roof is completely failed cedar shakes with a lot of exposed sheathing throughout.

In Green building techniques | Asked By Roger Smith | Oct 20 16
9 Answers

What's the best way to renovate/rebuild an old south-facing exterior wall?

Hi All - I am a newbie to this group but have considerable building experience remodeling and renovating homes, and completing unfinished properties. Still, I am no expert building contractor.

In Energy efficiency and durability | Asked By Roger Smith | Oct 2 16
2 Answers

2016 heat-pump water heater rebates - Opinions on best heaters?


There is a $750 Massachusetts rebate on air source water heaters. There are a lot too choose from. Any opinion on which one would be the best choice for a small 2 bathroom?

Thanks for any input.


In Green products and materials | Asked By Seth Capista | Oct 18 16
2 Answers

Attic insulation

I'm curious if anyone has any advice with concern to insulating an attic that contains a gas furnace (sealed combustion)? The unit is placed pretty close to the rafters- about 8"- and the attic is only about 5' at the ridge. Is it best to create a conditioned space for the unit or the whole attic? I'm new to all of this, so I'm not sure what to watch out for. Any advice would be appreciated. Also, does anyone have any recommendations for insulation contractors in the Boston area?

In General questions | Asked By Jeff Cannon | Oct 15 16
13 Answers

High Performance Home definition in as few words as possible.

I would like to see something less than an elevator pitch that gets to the route of what a high performance home is for the average potential new home client. Everything is too wordy and goes into air sealing, superinsulation and the why and the how - too much eyes-glazing-over detail. We need more of a slogan in this business. I'm putting it out there as a problem to work on. 140 characters perhaps?

In General questions | Asked By Robert Swinburne | Oct 17 16
3 Answers

New HVAC not blowing cold enough... what are the common causes?

I have just had a second new HVAC unit installed. A Trane xr17 condenser and s9v2 furnace. it is installed in my conditioned crawlspace, and I have an identical setup in my foam encapsulated attic.

In Mechanicals | Asked By John Sexton | Oct 18 16
7 Answers

Mitsubishi minisplit reconfiguration


In Mechanicals | Asked By Ben Thrush | Oct 17 16
1 Answer

Can 1.5" and 2.0" unfaced XPS be used as a continuous rafter baffle?

I am considering using either 2.0 or 1.5 XPS as a continuous rafter baffle (from soffit to ridge vent) using a 2" vent between the XPS and the the roof deck. The rafters are nominal 2x10s and the underside of the rafter will be insulated with Roxul and then covered with finished plywood with a high quality latex paint (Class II or preferably Class III vapour retarder). I have only seen 1" XPS recommended by GBA. Can a thicker board be used or is there concern re: drying to the exterior given the relative impermeance of the thicker board?

In GBA Pro help | Asked By Andreas Seibert | Oct 18 16
1 Answer

Replacing siding on an old Toronto house


I need to replace the siding on my house. I've read through this article, but still have some questions:

Some info:

In General questions | Asked By Jon Haque | Oct 18 16
Register for a free account and join the conversation

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