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!

8 Answers

Gas heated steam radiator system


Asked By Daniel Herskowitz | Dec 5 13
0 Answers

All Electric vs. Natural Gas in Zone 2

I'm building a house in Houston, Texas. It will probably be a 'pretty good' house - dense pack cellulose and exterior rigid foam installation with an encapsulated attic and targeting an ACH50 of <3 with an ERV system for ventilation. I will have a sizeable solar PV array on the roof - 6-8 kw so I have been debating whether to use natural gas as in my current house for multiple appliances or go all electric. Pros and Cons as I see them are:

Benefits all electric:
No standing monthly charge of $25 for gas since consumption is below threshold 9 months of year

Asked By user-6822325 | Apr 22 17
12 Answers

Insulating new construction home with no exterior rigid foam

Okay smarties, here is my scenario:
-I am Building a new home that is currently in the framing stage. 2x6 studs with Forcefield Sheathing (essentially same as ZIP).
-I am in in Climate 5 (iowa)
-My home is a California style architecture, 1.5 story, pitched roofs (now I realize why this is better suited for CA-vented roofs better option in Midwest!)
-My initial goal and how I came across these articles was to prevent mold (still is)

Asked By user-6809983 | Apr 9 17
1 Answer

Hip Roof in zone 6A

My client is a builder who has already completed the exterior siding and roofing of a new house in coastal Maine (zone 6A). The hipped roof and 2x6 walls have no exterior rigid insulation and no air space between cedar shingles and Typar. Walls: 2x6 with R-21 batt (John Mansfield), 1/2" CDX, Typar, cedar shingles. He plans to install shiplap hemlock paneling to the interior. Roof: Hip, 6 in 12 pitch, 2x10 rafters into (2) 11 7/8" hip rafters. Also has two dormers.

Assuming we go with an unvented assembly, how do we best achieve a vapor seal?

Asked By user-6825743 | Apr 22 17
16 Answers

Need sizing advice on a minisplit unit

I installed a Mitsubishi FH12NA in summer of 2014 when they first came out. I live in inland San Diego, and it can get hot, like 10-15 degrees hotter than the coast.

My condo is a studio and is only 420 sq ft. I'm on the upper unit of 2 stories. I face East and South. I have a skylight and dual-pane windows. Building is 1978 construction.

My Mitsubishi is weak. I set the temp and it will barely do anything. I have to set the temp to 61 and manually put the fan on high for it to do anything. Even "powerful" mode is weak.

Asked By aypues | Mar 16 17
4 Answers

Raycore - is it the product for me?

I was pretty much on board with buying Raycore for the 4500 s.f. home I am building in downstate NY, which is steel framed, so I actually don't need any structural value out of the exterior walls other than for supporting the windows and doors (and supporting the walls themselves). I am also going with a wire lathe and stucco on the exterior - Raycore told me I could direct apply the wire lathe and did not have to use any sheathing if I did not need the shear strength, but I am hesitant to do so.

Asked By Joe McCarthy | Jul 14 14
28 Answers

Wall moisture monitoring

I'm diagnosing a tricky moisture issue. Part of the process has involved the use of wall cavity humidity and temperature probes. I have some data and I'd like to "peer review" some of the findings in broad strokes.

First off, this great article got me thinking:


Asked By Rob Simpson | Mar 6 17
3 Answers

Modifying Existing ICF Walls

We are considering purchasing a house built completely with ICF walls. Our purchase is predicated on being able to expand windows in two areas and lengthening a current window area to install french doors to a deck. The expansion of the windows would involve removing the wall between two windows and installing a wider three panel window.

Is this possible with ICF construction. If so what are the key things that must be considered in making these modifications.


Asked By ledICF | Apr 22 17
9 Answers

2x4 rafters, skip sheathing, no insulation, help with roof choices

The shingled roof on my 1940 farmhouse in Zone 3b is due to be replaced. My wife and I are considering the virtues of metal for our very hot, very dry climate where electricity often exceeds $0.40/kw hr.

I plan to remove what little insulation is presently on the attic floor. The hvac ducts are also in the attic with little insulation and are likely poorly sealed.

Asked By Edgar Pankey | Apr 20 17
3 Answers

Insulating under a raised floor

We are planning to build a timber-framed raised floor in one section of our house. Currently this section is 1-2 steps (7-14") below the main level of the house, and is slab on grade. Long ago this was a garage.

We live in central NY, climate zone 6.

The 1970-s vintage slab is totally uninsulated to the best of our knowledge. We will add a plastic vapor barrier above it before placing the raised floor framing.

Asked By David Hollman | Apr 15 17
Register for a free account and join the conversation

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