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!

0 Answers

Insulating an historic house's attic

Hi all!

I live in Montgomery County, PA, which is at the northern edge of the 4-A climate zone according to the map on this site.

In Plans Review | Asked By Robin Klingsberg | Jan 15 17
5 Answers

What is correct installation of rigid foam board on roof, at seams of each panel?

What is the correct means to seal the seams between foam board applied on top of roof sheathing? What is the impact of incorrect sealing? Background: we contracted with a roofer to apply 4" of Atlas nailbase on top of the roof sheathing, before shingling. I happened to look at the roof on a recent cold morning and noticed gridmarks on the roof, indicating areas where frost had either melted, or had not formed, due to heat loss between the seams of the nailbase. I would think if the seams had been sealed correctly there would be no visible frost lines.

In Energy efficiency and durability | Asked By Jim Berry | Jan 11 17
0 Answers

Hydronic radiant heat over concrete slab

I'm building an addition that partly includes an extension for an existing room off one side of my house here in Connecticut. Existing floor is 2 1/4" x 3/4" oak strip hardwood floor. Addition floor will be slab-above-grade with poly and rigid foam underneath the slab. Need to "marry" the existing oak floor (conventional wood subfloor/structure) to new concrete slab using new oak strip flooring. Because I'm building this addition myself, there will be more than sufficient time for the slab to dry (perhaps a year or more) before new finish flooring needs to be installed.

In General questions | Asked By John Rooney | Jan 14 17
4 Answers

Soffit vent with spaced boards and hardware cloth

I'm figuring out how I want to vent sloped soffits under a shed roof. I'm considering stapling galvanized hardware cloth across the bottoms of the rafter tails, and then installing 1x boards perpendicular to the rafter tails spaced to allow ventilation. I've drawn my idea (not to scale.)

The rafters have v-cut blocking at the exterior wall. The v-cuts are the limiting factor for the ventilation area, so the soffits need to be fairly open to airflow.

I have a couple questions:

A: Does this seem like a good idea?

In General questions | Asked By John Ranson | Jan 13 17
10 Answers

Pond pebbles instead of crushed gravel for the driveway - what to do?

Our general contractor received a wrong kind of gravel for our big driveway install. We have 1500 sf to build and 1/2 of it is a concrete driveway and 1/2 permeable pavers. We have 2/3 of the total rock needed already on site. And that rock is pond pebble instead of limestone gravel that would have properly compacted under the driveway. Supposedly this cannot be returned. What are we to do?

In General questions | Asked By Lucyna de Barbaro | Apr 30 16
0 Answers

Can Roxul Comfortboard 80 be installed on roof deck in non-vented assembly 70psf load requirement?

Passive house build in Northern California

In Green building techniques | Asked By Forrest Kerr | Jan 14 17
0 Answers

Cold access room - Air barrier gaps between roofline and exterior wall

Hi Everyone,

In General questions | Asked By Joe Duchek | Jan 13 17
10 Answers

Please pick my plan apart- better now than after it's built.

If anyone wants to provide input it would be greatly appreciated.

This is to be our retirement home. Energy efficient, double stud walls, the walkout is to the south. Masonry wood stove in living room.

Please note the three level breezeway. I struggled with window sizing and ended up with a lot of different sizes based on room use not exterior balance. Not good?

The South First floor overhang is too small. My designer/draftsman changed it to give upstairs windows some room. That will change and go to 9' ceilings in upstairs if needed.


In Plans Review | Asked By jim sweazey | Jan 13 17
6 Answers

Triple pane vs. double pane in Phoenix

Im at the point where I have to narrow down my material choices for my new home build. Im in PHX, living in a home built like this : http://www.greenbuildingadvisor.com/blogs/dept/qa-spotlight/why-are-hous... . And its driving me nuts having to pay my electric bill every summer ($500 a month and thats with solar!!). Currently I have spec'd Intus triple pane windows (Vinyl Arcade line, not the higher end Eforte) for their U Factor (high 0.10's). I'm the opposite of most as I am trying to block the introduction of heat through thermal transfer not the loss of it.

In Energy efficiency and durability | Asked By Jeffrey Savage | Jan 12 17
12 Answers

Mini crawl space

I have decided to convert a piece of my timber frame barn into living space on my new home.( the barn is there) what I would like to do is elevate a 2x 8 floor above the existing slab. This would hanger onto the existing perimeter grade beam that sits on top of the concrete stem walls. I would set the floor 1.5" higher than the grade beam to create a thermal break with a narrow ripping of eps. So I would end up with about 10 inches beneath the floor assembly.

In Energy efficiency and durability | Asked By scott mangold | Jan 7 17
Register for a free account and join the conversation

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