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!

3 Answers

1953 unfinished attic floor, storage, retro install; overkill?

It looks like we've got R9 and want to get up to a total of R49 rating. There's lots of good storage space with solid wood flooring on the attic floor joists. We hate to lose all that space (and especially if we resell think it's a selling point) to blow in. I'm looking at DIYing but find so much contradictory information and opinions online it's hard to sort it all out to a novice and first time home owner. I will tell you where I live we're in zone 6, so it does get cold here.

In Energy efficiency and durability | Asked By Josh Thompson | May 7 15
15 Answers

Geothermal - Sizing Issues - 4 Ton or 5 Ton?

I live in Cincinnati, OH and I am zeroing in on purchasing a geothermal heat pump for my 5800 SF (conditioned) home. My home is all electric is currently heated by an 8 year old 4 ton air source heat pump with 15Kw electric backup. My issue is the two geothermal companies I have contacted to quote the job disagree on heating load of my home. Both companies did Manual J calculations, but are coming up with different numbers. One company has the heat load at 55k BTU -- says a 4 ton is the way to go. The other company has heat load at 68k BTU - says go with a 5 ton unit.

In Mechanicals | Asked By joel perrine | May 3 15
6 Answers

What's a good damper for a bath fan/range hood vent?

My bath fan vent is basically a big hole in the house to the exterior and sucks air out of the house in the high New Mexico winds, which today reached 30 mph. There's no damper or air check valve or anything like that installed up there, and I'd like to rectify it. What do people use for this situation? A standard butterfly damper? Something louvered? This thing? http://www.batticdoor.com/bathfandraftblocker.html

In Mechanicals | Asked By Nathaniel G | Nov 23 14
17 Answers

Need condensation control — Want a bath vent without another 4" hole outside

Any brainstorming helps.
Have "sealed" window in bath anyway but do not want to open in winter north Iowa.
Radon vent (other side house) condensates.
So I don't want to make another 4" hole for bath vent.
When I turn on radon fan I hear water slosh down in pipe that's horizontal.
And dryer is another 3" hole. That condensates too. (I tried manual fix. See pics.)
And vent stack is another 4" hole.
And gas water heater is another 3" hole out chimney.
And water pipe is another.

In Energy efficiency and durability | Asked By Charlie Darwin | Apr 30 15
3 Answers

Why select 3D EPS Panels over conventional?

Hi…As I am thinking about getting my own house constructed over 1000 sqft of area, 2BHK. Therefor I was generally looking for options and came across 3D EPS Panel technology which claims that it saves on time, labor and cost. However the contractors that I have spoken to and GBA Advisor Martin Holladay were not in favor of this technology due to its high cost. Therefore I am a bit confused whether this technology is actually cost effective or costly.

In Energy efficiency and durability | Asked By suraj kaul | May 6 15
5 Answers

Relative humidity conundrum

I have an Aprilaire automatic humidifier installed in the return air duct of my HVAC.
The Aprilaire displays RH% and is presently set at maximum (5,000 s.f. home) because we have had a problem with our wood floors drying out too much during the winter. The conundrum is that, for example, when the Aprilaire displays 45% RH, my hand-held RH meter may display only 30% RH. The obvious check of using the same meter in the return duct air stream confirms that the Aprilkaire reading is correct. So how can the 2 readings be so different when the Aprilaire is reading the returning air stream?

In General questions | Asked By Chris Simmons | May 5 15
5 Answers

Deciding between power vent and chimney water tank

My current water tank is rusting, rental company screwed up and it rusted prematurely, when i replaced my chimney vent furnace with high efficiency i was told the "orphan" water tank may have back drafting issues which did not happen, but the water tank anode was already gone and it was rusting internally. I figured when the water tank was getting old 5-10 years from now i would go with dual pipe power vent but it died prematurely.

In Energy efficiency and durability | Asked By Alan B | May 4 15
4 Answers

XPS foam on basement wall with no sill plate gasket

I am in the process of redoing my basement and would like to insulate the walls, but I don't really know what type will be the best. My basement walls are constructed with hollow concrete blocks and the the sill plate is non-pressure treated lumber resting directly on the concrete block with no capillary break (home built in the late 70s in climate zone 4A). The exterior of the house is brick veneer and the sill plate is about 6 inches above the level of the soil.

In General questions | Asked By Tracy Burcin | May 5 15
3 Answers

Spray foam covers entire 2x4 on roof truss...bad?

I had my roof deck sprayed with spray foam (to the underside of the truss). My roof trusses were designed at 16" OC and constructed with 2x4's. They needed to spray 4" of foam to get the code requirement for insulated value, so they covered the 2x4's completely on the roof deck.

Now I'd never really looked at and or thought about it till after they were done...(should have had the trusses designed with 2x6's) but the 2x4's are fully encapsulated with foam. I'm worried they are going to rot because they can not breath. Is is not a big "no-no" to encapsulate wooden studs?

In General questions | Asked By Mark Helmrich | May 4 15
1 Answer

Fixit 222 Aerogel

It was mentioned in the 2015 Passivhaus conference article, what is its cost and R value?

In Energy efficiency and durability | Asked By Alan B | May 4 15
Register for a free account and join the conversation

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