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!


1 Answer

Where to put the water barrier?

Hi,
I'm going to retrofit rigid foam over a log home in Vermont. The logs are 6 inch pine logs, that have an R value of about 9, they have a clapboard cut on the outside so the house will not appear any different with a 3 inch layer of foam insulation with a rain screen and clapboard.

My question is about where to put the tyvek, on the out side of the foam or under the foam? We are replacing all the windows and doors. It would seem to me that the tyvek belongs on the outside of the foam and over the flanges of the new windows and doors.

In GBA Pro help | Asked By Thomas Gardner | Jul 2 15
3 Answers

Can a feature be added to e-mail on a reply?

If i want to follow a conversation, I have to come back to it and sometimes it ends up on the second or third page. It would be very convenient that once I reply to someone's question, I get an e-mail when it gets replied to by someone else.

In General questions | Asked By Alan B | Jul 1 15
2 Answers

Older home (1950s) smells of mildew...

I purchased a home in late 2009 and have been trying to get rid of a heavy mildew odor. Last week I discovered the seller had put vinyl siding over two layers of other siding. Underneath the vinyl was a layer of extremely damaged Boise Cascade panel siding. It was crumbling and had large holes in multiple places (no house wrap). Behind the holes I discovered clear plastic sheeting and underneath that was cedar lap siding. I continued on down to the Buffalo board that was somewhat warped and had a strong mildew odor.

In General questions | Asked By Terri Goodheart | Jul 1 15
5 Answers

Air sealing exterior walls in a benign climate

Hello Martin,
I am removing and replacing the siding on an old Victorian located in Berkeley, CA which I believe is climate zone 3. After stripping off the old layers of siding, we will insulate, install plywood sheathing, (nailed at 4 at eh edges and 6 in the field for seismic stiffness), and then a drainable house wrap and fiber cement siding.

In Green building techniques | Asked By Craig McCaleb | Jun 20 15
2 Answers

Inground gutters

A few years back I came across an article in Finehomebuiling about inground gutters. Has anyone tried this solution to wet basements? Does it work?

In GBA Pro help | Asked By Daniel Cimaglio | Jul 1 15
14 Answers

Foam over a concrete floor

I plan 4 - 6 inches of EPS under the slab and now am considering an inch of either EPS or XPS on top with 5/8 or 3/4 tongue and groove plywood or OSB to provide a nicer floor to walk on as well as a warmer floor in the walk out basement. I think this will make it easier to attach partition walls and tile in the bathroom and hardwoods in the sunroom.
Question. .. Is this a good idea, and do I glue the foam (EPs or xps) to the concrete and the sheeting to the foam or leave it free floating?
Any gotchas in this?

In General questions | Asked By tim brown | Jun 29 15
2 Answers

Choosing a solar (PV) system

Hi, I am completely new to solar and considering proposals from a couple of contractors.

One is proposing a 3.1 kW system of (9) 345W SunPower panels with a SunnyBoy inverter located on a south facing roof.

The other is proposing a 4.2 kW system of (14) 305 kW LG panels with a Fronius Primo 5.0-1 inverter, with panels located on a south facing roof plus on a basically flat roof adjacent to it.

In General questions | Asked By Nancy Hartman | Jun 30 15
4 Answers

Open-air barn

We are designing an unconditioned "party barn" in Central Texas for occasional gatherings for groups of various sizes. The barn has about a 1,400 sf footprint -- 1,400 sf at the ground floor then there is a loft that is about 200 sf. We have Big Ass Fans for air movement but would like to add an attic fan to exhaust the warm air that will build up in the loft/attic space. How do we calculate the amount of CFM that the fan should be moving?

In Mechanicals | Asked By Heather Gayle Holdridge | Jun 26 15
2 Answers

Spray foam insulation in attic?

I want to insulate a walk-up attic in a 100+ year old home in climate zone 6. I need to add insulation because there is only about a foot of blown in cellulose under the floor boards in the attic. I don't want to blow in more cellulose because I am thinking about finishing the attic for more living space. I am thinking about having closed-cell spray foam insulation applied against the roof sheathing. The rafters are only 2x4s and I am thinking about firring them out two to three inches to accommodate 5-6 inches of foam.

In Energy efficiency and durability | Asked By T S | Jun 27 15
4 Answers

Closed-cell spray foam in conditioned crawl space, sill gaskets, windows, & air sealing

We have our house plans back from the designer and are getting ready to start building. I have a few separate questions:

In General questions | Asked By Michael Geoghegan | Jun 30 15
Register for a free account and join the conversation


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