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1 Answer

Liquid-applied WRB in an attic?

I have an upcoming project on several older buildings to abate asbestos containing vermiculite, used as loose insulation in the attics.

Basically, the contractor vacuums out the vermiculite, and as the final part of the abatement process sprays a sealer over interior of the attic, to immobilize any remaining asbestos.

I was wondering if I could specify that the contractor apply a Liquid Applied WRB on the interior of the attic, and then install an R42 blow in insulation.

Any thoughts?

In Green building techniques | Asked By Randall Thomas | Jun 12 16
2 Answers

How can I keep my second floor cool?


In General questions | Asked By Barbara Tarnoff | Jun 11 16
12 Answers

Minisplit sizing

When comparing specs from the same model line I noticed that the maximum BTU/h goes up as the tonnage goes up but the minimum BTU/h for heating, stays about the same.

Let's compare 2 units for heating.
9000 BTU/h --> 5700-11910
18000 BTU/h --> 5620-18540

Assuming the same price, which unit would be the best choice with a 9000BTU/h house?

In General questions | Asked By Tony Tibbar | Jun 12 16
13 Answers


I am trying to come to grips with SEER, COP and HSPF.

Is this correct:
SEER is BTU cooling / watt hours needed. So divide this number by 3.412 to get the COP. Thus a 16 seer unit would have a COP of 4.7 or so.

HSPF is BTU heat produced / watt hours needed. So take a heat pump with a HSPF of 10, which is supposed to be pretty good and divide that by 3.412 = a COP of 2.9.

Have I done that correctly and, if so, are there heat pumps that do better than a 10 out there?

In GBA Pro help | Asked By Amanda Evans | Sep 10 09
10 Answers

Can one use a slab-over-slab radiant heat system?

Thank you all that answer my question.
Here is my question in short form:
Pole barn that was built as a small factory to be revamped to a new business and add radiant heat?

Can one add the heat system on the current slab and re-pour a new slab on top, where height and doors are not a issue? or Should one cut out the old slab add needed equipment and re pour a new slab. Again or Could new construction be a better option? Time and cost factors are important.
As a added note this is in mid northern Minnesota.
If you need more just ask. Thank you again!

In Mechanicals | Asked By Ken Jackson | Jun 10 16
2 Answers

Minisplit short cycles only in heating mode

Hi, I had a Fujitsu 15RLS3 mini-split heatpump installed for the first floor of our house (~1000 sqf and fairly open floor) in March of this year. During the heating season, even with fairly low outdoor temperature, such as high 30s or low 40s, the unit would short cycle tremendously, sometimes at intervals of only a few minutes.

In General questions | Asked By matthias paustian | Jun 12 16
1 Answer

Why is this brick eroding?

I have an interesting thing happening to my brick chimney. We noticed that two of the bricks, their faces, kind of crumbled off. Not the white powdery residue but actually powdered off in the same color as the brick. Looking for a reason why this might be happening. We live in Missouri (St. Louis). In the pictures the picture labeled "Brick 2" is what the effected brick looks like. The other picture is a typical smooth brick on our chimney.

In General questions | Asked By Richard Hogan | Jun 11 16
7 Answers

Alternatives to TimberSIL

We are designing a commercial project in Gulfport, Mississippi where we were planning to use TimberSIL. We were looking for something that was durable, low-maintenance, and highly resilient in addition to being environmentally friendly. We chose TimberSIL since it was one of BuildingGreen's Top Ten Green products several years ago, was the first non-toxic preservative product approved by the EPA, had been around for over a decade, and seemed to have one of the best warranties available among pressure-treated woods.

In Energy efficiency and durability | Asked By Heather Gayle Holdridge | Dec 30 13
6 Answers

Dehumidifier: running too much OR poor energy efficiency?

I just installed a 30 pint dehumidifier in the basement of my single story 900sqft house.

It uses about 4kWh per day to maintain a set-point of 55%, as measured by a Kill-a-watt.

I'm in Chicago, Zone 5.

My electricity bill without the dehumidifier from March-April was about 200 kWh/month.

Last month, with the dehumidifier turned on midway through saw a usage of 240kWh/month. A/C has not been used yet.

How can I determine if that 4kWh energy usage is due to it just running too much (e.g., too small for conditions?) or if the equipment just takes too much energy to run?

In General questions | Asked By Jeff Watson | Jun 6 16
5 Answers

Framing factors

I am trying to calculate framing factors for walls. I read that until 1993 ASHRAE recommended using 15% for 16"oc walls and 12% for 24"oc. Then in 1993 they revised these to 25 and 22. Is this still what people are using? Also, how does this change for walls that use advanced framing techniques? Is there any resource that gives this information?

In General questions | Asked By Amanda Evans | Sep 11 10
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