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!


4 Answers

Structural support for windows/door with exterior insulation

I am doing a large renovation that will involve adding 3" of rigid foam insulation and I'm installing triple pane Inline Fiberglass windows that are quite heavy and I'm concerned that the methods that I've seen will not have enough structural support for the windows and sliding glass doors. What I have seen is having 3/4 plywood bucks that span the entire opening (from face of exerior insulation +/- furring strips to the face of the interior framing).

In Green building techniques | Asked By Joshua Rogers | Feb 10 11
1 Answer

I-joist blocking

Laying out shop lighting..just some 4' led strip lights. Can I use the attached method to wire my fixtures right where they need to be? I see install guidelines for I joists that say "no nailing the flange" how would these small blocking pieces be secured to the i-joist....wanting to use dense pack after all plumbing and electrical is done so I'm not wanting to create a full blocking from bottom of 2nd floor subfloor to top of 1st floor ceiling.

In General questions | Asked By Inger Peters | Sep 20 17
7 Answers

Best way to plumb for outdoor shower (with hot water)?

Hi guys,

I am wanting to have an exterior hose bib that allows for hot water, so I can hook a shower up to it.

Because I am in a tiny house on wheels, my walls are only 2x4. The only product I have found is woodford hot/cold bib http://s3.supplyhouse.com/product_files/Woodford-V22CP-4-MH-Submittal.pdf

Unfortunately, even for the 2x4 model, it's 5 7/8" long. So this product would stick out on the interior side.

It's also important to note that my one piece corner shower will be on the same wall, so there is no room to come out on the interior side.

In General questions | Asked By Grey Wolf | Sep 12 17
1 Answer

Cut and cobble - basement ideas?

Hello all,

I'm located in western Washington, zone 4 marine, and we're working on our early 1970s split level. When we purchased the home last year we ended up needing to put in a sump pump and interior footer drain. Since then, we've been monitoring the walls and relative humidity. There's been no new evidence of moisture and later this month we'll be installing a new heat pump and plan to use the dehumidifier function.

In General questions | Asked By user-6921457 | Sep 19 17
9 Answers

Insulating a low-slope roof

Hi Martin,
We are ready here to go ahead with the insulation of our low-slope roof, and decide to go with closed-cell sprayed foam as you recommended.

We had 3 quotes from local company, and 2 of them proposed to shoot 5-6 inches of foam underneath the 1st deck (in green in the following image), assuming we would remove the interior ceiling.

In Green building techniques | Asked By Francois Desrochers | Sep 6 17
2 Answers

Legalett slab for Sequim, Washington

I am building a home in Sequim, WA. My architect is finishing up the design and construction will begin next year. I plan to use a Legalett raft slab with the air radiant floor heating system. Sequim has a marine climate and gets an average of 16" inches of rain per year.

I am looking for feedback from anyone who has built with a Legalett slab. What was your experience with the vendor and how the slab has performed?

In Plans Review | Asked By David Van Cleve | Sep 18 17
4 Answers

How to protect a wood foundation

My house is a walk-in bungalow built into the bottom part of a hill in 1985 approx. and has a wood foundation.

With the high levels of humidity this year, I was concerned about the indoor air quality. Among other measures, a local contractor has commenced excavating around the house, allowing the foundation to dry and is inserting some drainage around the building. The foundation appears to be in good condition. I am also looking into other measures inside the house.

My issue is I’m now getting very conflicting advice on how to proceed moving forward.

In GBA Pro help | Asked By Chelsea 7T | Sep 19 17
6 Answers

Make up air and multi zone sensor

I do instal 600cfm rangehood in my kitchen. Vented outside of course. I have also motorized damper supplied by the manufacturer and it will be installed on the dedicated make up air duct being controlled by the switch on the hood. This part is clear. What is less understood is the question of preheating this make up air supply. The climate is cold up here and air, if not preheated, will mess up the whole system. Of course, company like Fantech offers elegant solution but... what if... Ecobee makes a thermostat with multi zoning temperature control sensors.

In Mechanicals | Asked By D.Kits | Sep 17 17
2 Answers

Z-girt, insulation board, and metal siding

I'm building a cabin out of Faswall hybrid ICF blocks and plan on adding an additional 3" of Roxul Comfortboard on the outside wall before installing metal siding. I had planned on using one layer of 1.5" Roxul then screwing 2x4 furring strips in place with an additional 1.5" of Roxul in between the furring. But wouldn't it be more efficient to just use metal z-girt strips with a 3" web to support both the Roxul and to mount the siding to?

In General questions | Asked By David Williams | Sep 18 17
10 Answers

Is there a reason people do not use hydraulic cement to parge an entire stone basement?

I have a stone basement in Wisconsin. It's depositing sand along the edges of the walls in various spots. Not bad, and it only leaks a small drizzle of water if there is a huge downpour, but I want a clean water tight basement.

In Energy efficiency and durability | Asked By PFields | Sep 17 17
Register for a free account and join the conversation


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