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12 Answers


Apologies if this has been covered many many times...

I am building a garage, with rental apartment above, in Rhode Island.
- Climate zone 5 (or 4-Marine? The humidity-controlled bathroom fan seems to run all summer, windows open)
- 24x36, approximately 800 SF of living area, unheated garage area.
- Glazing: Lots on the South (view) side, minimal on E, N, & W. Mid-range manufacturer.
- Framing 24" OC throughout: 2x6 walls, 2x10 (or 12?) floor, complex truss roof.
- Siding 50% wood shingles, 50% cardboard-cement clapboards (matching the "big house")

In General questions | Asked By curtis betts | Mar 12 13
4 Answers

Support for 16 inches of cellulose over dropped ceiling?

We have vapour retarder membrane under the flat part of the roof trusses but want to reinforce that to hold up the 16" cellulose in attic as there will be no drywall there (dropped ceiling). Lath or chicken wire are the only two options that come to mind - any other cost effective and efficient means of providing support to prevent sagging, popping staples and voids?

In Energy efficiency and durability | Asked By Patrick Walshe | Mar 15 13
4 Answers

Interior rigid foam installation

I am remodeling a 1905 Folk Victorian (code for farmhouse). The majority of the house is 2x4, with the exception of an addition which is 2x6. I looked into foam exterior but it would involve removing a lot of original molding and architectural details that add to the house. With spray foam at $7000, it is a $6000 premium over fiberglass. Not worth it. This is where I decided to go with XPS on the interior (or even polyiso).

In Green building techniques | Asked By Ryan W. | Jan 3 13
16 Answers

Maximum Insulation in Thinnest Wall


I live in downtown Toronto (Zone 6), Canada. I'm building a brand new addition to an existing 1888 brick house, on a narrow 17' wide lot. I'm interested in getting the best thermal performance (R40) within the thinnest assembly (11" wide) so here is my idea:

From inside to outside -
5/8" GWB
2x4 wood stud framing with
3.25" of high density spray foam (R21)
1/2" plywood
air barrier
5" Roxul Mineral Wool (R20)
1" wood battens or alternately 6" thermally broken z-girts
metal cladding (I am hoping to use a flat seam metal panel of some sort.)

In GBA Pro help | Asked By Jeanne Ng | Mar 12 13
24 Answers

Reflectix still claiming R4.2 for its bubble wrap - my HVAC guy is hooked

After reading up a bit on this site, I am worried that my HVAC person is installing the wrong product on the metal ductwork that he is now hooking up. As I understand it, Reflectix bubble wrap might have some benefit in a very hot unconditioned attic where the ducts are carrying cold air. But in my case, the opposite is true: the ducts are carrying hot air only and they are located in a cozy spray foamed attic. Mold formation is not an issue here (the basement is a different story, alas).

In Green products and materials | Asked By rich cowen | Mar 25 12
11 Answers

What size heat pump for a very small house?

I am getting different opinions on the correct sizing of a ductless mini split air-source heat pump. the mitsubishi rep recommends an 18,000 btu unit but the daiken rep thinks we can use a 12,000 btu unit. thoughts? it's for a 610 sq' house with 8' ceilings, r38 walls and r60 ceiling in -32 design temp. we will use electric baseboard heat for back-up. thanks!

In General questions | Asked By erik olofsson | Jan 11 13
4 Answers

Please demystify cellulose grades and quality

Please demystify cellulose grades and quality ... why use one cellulose brand over another?

I need the best for dense packing, new construction dry material install and I want it clean of sulphates.

Otherwise why would I buy one brand over another. I see the following things talked about in the product descriptions:

concentration of boric acid
pure vs artificial boric acid
clean source of raw materials (paper vs cardboard)
insulation value based on fiberization and source of the cellulose
color and texture
dust content
particulate size

In General questions | Asked By Oak Orchard | Mar 14 13
1 Answer

What is the most cost effective way to retrofit insulation?

I have a home built in 1996, 3800sf with a pool that has utilities running almost $700 in the summer. I live in climate zone 3A. There are two a/c units with gas heat which are not efficient at all based on the yellow energy guide sticker. There are two gas water heaters. Both the a/c and water heaters are located in the attic. The tops of the ceiling joists are not covered by insulation and there is no radiant barrier. The second floor has some walls that border attic space (like a knee wall, but for the an 9ft wall). Several rooms also has cathedral ceilings.

In Green building techniques | Asked By joseph cochran | Mar 15 13
4 Answers

A basement for my double wall dream house

I've really struggled to find a solution to all the issues of putting an economical basement under a house built to the "pretty good house" insulation plan (r60 ceiling,r40 walls,r20 basement r10 sub slab). The ceiling is easy, cellulose is cheap and energy heal trusses routine. For the walls two common choices double stud or exterior foam.

In Energy efficiency and durability | Asked By Jerry Liebler | Mar 13 13
1 Answer

Window insulation

I live on New York's Upper West Side on a low floor. Our building is offering a bulk rate on window replacement through Skyline, either Skyline Series 100 Aluminum Double Hung Windows or Marvin Clad Ultimate Double Hung Windows.

Question - which is best for SOUND insulation? Is it worthwhile inquiring about triple glazing? Many thanks.

In General questions | Asked By WM hunt | Mar 14 13
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