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

Water damage mitigation, etc

Hey there,
Months ago, during a renovation to this house, the walls unfortunately caught a lot of moisture. It took a little while to figure out that the walls/insulation got wet, but once I did I turned up the heat in order to try and dehumidify from the inside. The plaster walls then seemed to get dry during the winter--I got moisture readings below 15%.

In General questions | Asked By jonathan nagar | Jul 27 17
3 Answers

What do you think of this new build in New Zealand?

Hi gang. I've been living in NZ for 18 months now and lately I've been working on a new house here. Previously I've been a builder in BC and I like to think that I produce warm cozy homes using the basic principles of building science like properly installed insulation and a detailed air barrier.

In Energy efficiency and durability | Asked By Marc Bombois | Jul 26 17
0 Answers

Rigid foam over existing drywall?

I'm planning on converting half my garage to living space, and I would like to add three inches of rigid foam insulation and another layer of drywall over the existing drywall.

The walls are 2x4 on 16" centers with fiberglass batt insulation, plywood sheathing (or possibly OSB), house wrap, and vinyl cladding. Can you think of any reason why this technique might pose a problem in my northeastern climate?

In Green building techniques | Asked By Ben C. | Jul 27 17
3 Answers

Humidifier and HRV in the high desert and other HVAC add-on items

We're building a 4200 ft home in the high desert (Bend, Oregon) and are debating several HVAC proposal add ons. The furnace plan is for a conventional ducted system with a Trane modulating furnace and variable speed AC. We unfortunately couldn't get over the split system interior look. The proposal had several add on items which seem controversial.

In Mechanicals | Asked By Ben H | Jul 26 17
2 Answers

Cellulose or BIBS fiberglass in 16" Ceiling Cavity ?

My house addition has an 800 sq ft ventilated attic. Ceiling joists are 16 inch I-Joists on 24" centers with 5/8 drywall underneath and 5/8 plywood attic floor on top.

The plywood attic floor is removable everywhere except the perimeter so that insulation can be blown from above into the 16" deep cavity. The current plan is to remove a row of plywood sheets on each side of the attic centerline. That will allow insulation to be blown from above and a maximum of 8 ft horizontally between the drywall and unremoved plywood.

In Energy efficiency and durability | Asked By Michael Tuso | Jul 24 17
0 Answers

Modified Edgewater Double Stud Wall

Marine Climate 4C

I have been working on a double stud wall design for a Pretty Good House. It is a variation the Edgewater design with inspiration from various other sources. I have redlined the air barrier.

It is close to complete, still working on some flashing details and material specifics. But perhaps good enough at this stage to share my progress.

Would appreciate any feedback or comment.


In Green building techniques | Asked By Tim L | Jul 27 17
0 Answers

Moisture control in unconditioned storage space under detached garage

Hello, we are building an unconditioned detached garage on a sloped lot in MD with a lower level that will be used as an additional garage space as well as storage for tools, power equipment, and even kids' toys and bikes. We would like to do our best to prevent rust and and mold in that space, but we have struggled with figuring out the best approach. This lower level space will be a 25'x35'x7' concrete cave with a slab on grade, a structural slab for a ceiling, and concrete walls that are on one end fully below grade, on the other fully above grade.

In General questions | Asked By KarlaMD | Jul 27 17
1 Answer

Energy efficiency upgrades during residing.

Hello GBA community. Newer to the website and newer homeowner, but have been studying and reading about building science. I live in Zone 5, have a stick frame house built in 1995 (1300 sf single family, one level). It is nearing time to replace my siding (roofing too) and I want to have a plan for some needed efficiency upgrades. I am trying to keep it simple and cost effective. Want to make some improvements, but this is not my forever home. I'd like to hash out my plan and ask for some critiques. Really appreciate your feedback and insight.

In General questions | Asked By Ryan Dutton | Jul 27 17
4 Answers

What is heating the floor in one room of my stilt home?

I live in the Florida Keys, in a frame home on concrete posts and beams. There is a carport with concrete pad on each side of a storage room at ground level, then two stories of living space. Double hip roofed. The house faces west. Every day in the summer, BEFORE THE SUN REACHES THE FRONT OF THE HOUSE, the floor in the room above the north-side carport heats up -- not the whole floor but eight feet or so nearest the front of the house. I measured the temperature rise and it is about 5 degrees - noticeable to a bare foot. The double window at the front is covered by a Bahama shutter.

In Energy efficiency and durability | Asked By hojgard | Jul 26 17
6 Answers

Install rigid foam while the wall is lying down

Has anyone tried installing the rigid foam EPS or XPS while the wall is on the floor deck and then installing the plywood over the foam overlapping foam seams before lifting the wall into place ?

In Energy efficiency and durability | Asked By susan cosentini | Jul 26 17
Register for a free account and join the conversation

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