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

Flat roof insulation?

I am converting the sun room to a bedroom
My concern is about the ceiling insulation and ventilation.
the roof is flat and not insulated at all.
The previous owner blocked all air flow from soffit using pieces of wood which also supports the roof.

During the summer time, the asphalt flat will be stressful because of no air flow.

In GBA Pro help | Asked By Mansig yoon | Jul 23 15
14 Answers

What is the most practical air sealing technique for new construction?

I am building a home in climate zone C4. My wall assembly will consist of 2x6's on 24" centers, OSB sheathing, then a layer of 1" XPS insulation, with my wrb on the outside of the insulation. I will then have rough cut reverse board and batten siding.

In Green building techniques | Asked By Kail Zuschlag | Jul 14 15
5 Answers

Fixing a central-fan-integrated supply ventilation system

I'm in climate zone 4A (VIrginia). My house has an upper and lower HVAC system. The lower system has a central-fan-integrated supply ventilation, roughly like the first diagram in this document:

http://www.greenbuildingadvisor.com/blogs/dept/musings/designing-good-ve...

[Editor's note: It appears that the poster intended to include a different link -- this one: Central Fan Integrated Supply Ventilation—The Basics]

except that:

In Energy efficiency and durability | Asked By Joe M | Jul 20 15
8 Answers

Fujitsu 12RLS3H in -25°F weather?

Does anyone have experience with running a Fujitsu 12RLS3H in -25°F weather, 5-6 hours a day for 8 weeks? I live in zone 7.

In Energy efficiency and durability | Asked By Matt Berger | Jul 22 15
0 Answers

Assist, LLC! Virtual Assistant Testimonials

“Very quick turn around … which has been great. Very good level of autonomy; we describe tasks with as much detail as possible, but Assist, LLC team has been really good as executing them well with minimal back and forth.”

Contact numbers: Phone numbers: (646) 233-3388
Address: 575 Madison Ave #12 New York, NY 10022

In General questions | Asked By diksaTrils diksaTrils | Jul 23 15
5 Answers

Cost effectiveness of one thick layer of rigid foam vs. two thinner layers?

Hi all,

We live in Central KY, zone 4a. We are shooting for a "pretty good house" standard for approximately r-30 walls. We are leaning toward a 2x6 frame construction, with blown-in cellulose, plywood or osb sheathing, a couple of inches of rigid foam, and brick veneer.

I see that it is most energy efficient to use multiple layers of exterior rigid foam so that you can stagger the seams. However, this obviously doubles the labor cost of adding the foam.

In General questions | Asked By Clay Whitenack | Jul 23 15
20 Answers

Buyer education versus a good code and intensive enforcement of it

This is kind of a general question. I'm seeing more and more issues coming up on GBA questions and answers regarding shoddy construction that homeowners are having to deal with. I read it recently in Peter L's description of some builders in the Phoenix area. This is most concerning when one is having a new home built, or purchasing a previously built new home, and it has subpar construction.

In Building Code Questions | Asked By Eric Habegger | Jul 21 15
3 Answers

Drying to the inside question

On homes with rigid foam on the outside of the walls, I know the house has to dry to the inside, so just latex paint or possibly a "smart" vapor barrier would be used on the interior drywall walls. My question is regarding the ceiling. I would probably be using blown-in celulose or similar (just a "normal" attic with ridge-vents and vents in soffits, etc), so would I want to poly the ceiling to keep the moisture out of the insulation? Can the house still dry to inside with poly in the ceiling?

Build will be right on the border of Zones 6 and 7 in Central MN.

In General questions | Asked By Brad VanVickle | Jul 23 15
4 Answers

Is my uninsulated garage making my house hot?

I have an attached uninsulated garage with its own attic, is that why it is so hot in my Austin, TX house?

In Energy efficiency and durability | Asked By K C | Jul 16 15
14 Answers

I need advice on the design of an energy-efficient heating system

Just completed re-framing a home in NH. Used Zip R on the outside, CC foam inside. I had planned on going with radiant heat but from the articles in GBA, this may be overkill. I have spoke with a few propane companies and 2 plumbing companies and have not seen anything that is right. Most do not seem to be up to date ( old school) Who out there can I contact to design the proper system without trying to sell me on their systems?

I am truly thinking of going with return hot water as this system has served us well in our last home for 25 years.

In Mechanicals | Asked By Joseph Maraldo | Jul 22 15
Register for a free account and join the conversation


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