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1 Answer

Spray foam fire-retardant painting

Recently I had my cellar a crawl space professionally sprayed with closed cell foam. The company was supposed to return to spray on fire-retardant paint. The crawl space is difficult to work in and they company has offered me several hundred dollars discount to leave it unpainted. They tell me that there is actually no requirement for the fire retardant paint in a crawl space, and that because there is no source of ignition in the crawl space, so it is safe. There is a living space directly above the crawl space.

In Green products and materials | Asked By JoshuaB | Mar 17 18
6 Answers

DIY air sealing equipment

Other than a blower door, which is impractical for this application, what specifc products do you recommend for a homeowner interested in air sealing? What is the best homeowner-grade thermal imager (if there is one), smoke pencil, etc?

Our moderate retrofit reduced a very leaky, large house from 7330cfm to approx 5000cfm, and I want to keep going.

Thank you.

In General questions | Asked By Emerson | Mar 13 18
2 Answers

Sheathing data logger

I'm working on a house with brick veneer that was built in the ~1970's without weepholes or base flashing and the 1" vent cavity is almost entirely filled with mortar. I'd like to add a data logger in my walls to track the moisture content of the sheathing, for personal interest. It's two layers, 1/4" OSB sheathing over 1/2" fiberboard. I was wondering if anyone could point me towards some reasonably priced sensors & data loggers that would work for this. Something that wouldn't require a lot of user interaction to produce useful data as well.

In General questions | Asked By Yupster | Mar 16 18
9 Answers

How to Reduce High Energy Costs for Ductless Minisplits

Hello Martin,

I have the Mitsubishi H2i heat pumps as my primary heat source at my south east MA home. Seven indoor units [9 and 12K's] and two outdoor units [MXZ-3C30NAHZ, MXZ-4C36NAHZ]. The 2,400sqft 1980 contemporary style house has lots of [1st gen. Anderson double glazing and Pella single with interior "storm" panels] windows. The Pella's are actually [relative] better thermal performers. The wall insulation is typical of that generation, poor to fair. The attic has about 20" blown in insulation.

In Energy efficiency and durability | Asked By kazirode | Mar 16 18
9 Answers

Roof Insulation Approach

I'm building a single story addition and researching roofing insulation options. I'm considering an option where I use 11.5" ijoist rafters with a luan panel nailed to the bottom of the top ijoist flange in each rafter bay creating a vent channel from soffit to ridge. For insulation - total to be R49 - I would install 2" foil-faced polyiso to the underside of the ijoists and foil tape it to create my air barrier. Finally, I would dense-pack cellulose the rafter bays through holes in the polyiso. So I believe I have my air barrier on all sides of the cellulose.

In General questions | Asked By John Rooney | Mar 15 18
5 Answers

Load calculations vs. actual fuel use

I've done my own fairly in-depth heating load calculation, tweaking and re-thinking certain aspects over time as I've learned more, and my result is 10,800 BTU/hr.

Today I decided to analyze my electric bills to reconcile theory vs. reality. What I found is that, despite a lot of attention to accuracy, I think I still over-sized by a lot. My heating load appears to only be about 5,800 BTU/hr.

In Energy efficiency and durability | Asked By Nick Welch | Mar 15 18
11 Answers

ZIP, AdvanTech, OSB, and Plywood.

ZIP, AdvanTech, OSB, and Plywood
What are people’s preferences/experiences when it comes to these products in the two following locations?

Roof Sheathing – Vented attic, with metal standing seam over top. Also what underlayment would you use with each?

Wall Sheathing- Inside to out lay-up is ½” drywall (hopefully fairly airtight) (possibly a membrane required by building inspector), 2”x4” studs, ½”sheathing taped (3M) (air barrier), 2 layers of 3” used fiberglass faced polyiso (6” total) Tyvek (WRB), horizontal ¾” furring strips, vinyl board batten siding.

In Green building techniques | Asked By Dave B | Mar 14 18
1 Answer

Not a question.. Listen to Martin Holladay on FHB podcast

I listen to this podcast every Friday and Martin was the feature guest (2nd time around for him) this week. It's always nice to put a voice with the name.


Excellent listening !!

In General questions | Asked By John Clark | Mar 16 18
7 Answers

This post is not about building science

The topic here has nothing to do with green building, so feel free to skip it and look elsewhere for a more relevant post.

My sister Meg spent a year living on the island of Lagonav in Haiti, where she volunteered as a teacher in a local school. Friends of hers on the island, including Jeanes, an agronomist, and Balaguel, Eligène, and Carlot, agricultural technicians, as well as two teachers, a school director, and a local government official, have set up an agricultural development project.

In General questions | Asked By Martin Holladay | Mar 15 18
9 Answers

DWHR and HPWH vs Electric, Total Efficiency?

So it's well known that a Heat Pump Water Heater (HPWH) is far more efficient at heating water than a standard electric water heater, but what happens when we look at the entire system top to bottom, including Drain Water Heat Recovery (DWHR) as well as the building's main heat source?

In Mechanicals | Asked By Lance Peters | Mar 15 18
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