Q&A: A Forum for Green Building Experts and Beginners

[Click map to enlarge]

Please register for a free account or sign in to ask and answer green building questions.

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!


2 Answers

How do deviations in average winter temperature affect energy consumption?

Off the top of my head I would expect a five percent colder winter to cost five percent more for heating, all things being equal.

Asked By norm farwell | Oct 24 14
12 Answers

Flat roof insulation

I have built an extension to my house with flat roof, continuation of the existing house. The rafters are 16 in apart and there is 6 in left for the insulation under the sheeting. The plans are requiring R30 insulation and the building inspector requested hard foam Thermasheath- 3, 5 in thick, leaving 1 in for breathing. The drywall was not installed yet, when water from condensation came down all over the place. There are vents on both sides of the roof, in each bay under the insulation level, not allowing the hot air to escape.

Asked By Angela M | Nov 22 13
10 Answers

What kind of insulation would you recommend for a 20' shipping container being renovated into a home/studio space?

I'm renovating a 20' shipping container into a home/studio space and am wondering what would be the best "green" insulation to use. I will be doing some interior framing so would like to insulate the inside walls and floor. As well, I am building a green roof/deck that is framed using the structural strength of the container (no weight on the center of the roof) and would like to add insulation between the joist supports and deck floor (approx 3" - 9" above the container roof) and the steel roof.

Asked By Sarah Beckstrom | Jan 19 14
4 Answers

Roof insulation

Home location in zone 2A Central Florida (Not on the coast). Having 2,053 SqFt living space w/above ceiling blown in insulation R-30 and an additional 1,027 uninsulated space. Fully vented at the soffet with minimal ridge vent. Soon to install 2 solar powered thermostat controlled 1600cfm roof vents. The wall construction is CMU block w/stucco finish. The roof is 6:12 pitch, Arch shingles over 30lb felt paper and OSB. The ceiling plane is tight.

Asked By Steven Clark | Oct 24 14
6 Answers

Add R-14 Roxul between the garage attic and the house?

I am currently in the process of insulating my attached garage using Roxul R14 "ComfortBatts". I live in Winnipeg and from experience -- when I did this in my last house -- it can improve the temperature by 10-15 degrees Celsius in the winter, without any heating. (And that was with a non-insulated garage door; my new house has insulated garage doors!)

Asked By Mike Lucas | Oct 23 14
9 Answers

Minisplit - One indoor unit for two adjacent rooms?

Do any of the minisplit manufacturers offer a wall mounted indoor unit that will service two adjacent rooms? I'm considering a minisplit to replace the gas furnace and a/c in my 1300 sq. ft. single level home in zone 3A (mixed-humid). Without a shared indoor unit on the common wall between two bedrooms, I might need five indoor units. The multizone minisplits seem to jump from 4 to 8 zones and the price jumps too. I understand the technical problems with one wall unit serving two rooms, but have any of the manufacturers solved them.

Asked By Steve Robertson | Oct 23 14
3 Answers

Will spray foaming my basement rot my sill plate?

Hi Martin or whoever would like to add input to my query. I live in Eastern Canada near the coast in a Zone 6/7 environment. I live in an old house with an low ceiling unfinished basement that is freezing cold all winter.

Asked By Chris McLean | Oct 24 14
5 Answers

Calculating how much air needed to even out temps for minisplit

I'm building an 800sf 2 story house, R20 under slab, R40 walls, R60 roof, as airtight as possible, but likely just double pane windows (due to cost). 12% glazing, mostly on south side, w/ 4" slab on first floor. Using Marc Rosenbaum's heat loss spreadsheet, I get around 4000BTHU building load here in Portland Oregon at the 97% coldest day of 23F and a design temp of 70F, so a delta T of 47F.

Asked By Tom Frisch | Oct 23 14
1 Answer

Radiant Retrofit Best Practice

We recently purchased a home which had a radiant retrofit in the basement approx 10 years prior. Our first winter (last) I noticed some mold showing through the finished flooring (4' x 8' wheat board). Long story short, I found 2 screws had pierced the pex and slowly corroded over the years finally leaking and ruining it all.

The layout was 6" wide 3/4" hardboard sleepers glued and nailed to the slab with 1/2" pex between. Over the pex and sleepers, 12" wide aluminum flashing was stapled and then finish flooring. The slab is insulated (2 layers of 2" polystyrene under the slab).

Asked By mie asdfav | Oct 24 14
4 Answers

Sealing meeting point of brick wall and asphalt driveway

Hi,

My house, a semi-detached, has an asphalt mutual drive between it and the neighbors house to the south that comes right up to the side of the house.

I'm concerned about the meeting point between the asphalt and the brick as it looks like water can collect there and seep into the brick (I have some Interior spalling and suspect that this is the source), but I'm not sure how to address this.

Do I use caulk.. or something with the consistency of tar.. or something like mortar for bricks..?

Some photos here:

Asked By Jon Haque | Oct 22 14
Register for a free account and join the conversation


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