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14 Answers

Foam over a concrete floor

I plan 4 - 6 inches of EPS under the slab and now am considering an inch of either EPS or XPS on top with 5/8 or 3/4 tongue and groove plywood or OSB to provide a nicer floor to walk on as well as a warmer floor in the walk out basement. I think this will make it easier to attach partition walls and tile in the bathroom and hardwoods in the sunroom.
Question. .. Is this a good idea, and do I glue the foam (EPs or xps) to the concrete and the sheeting to the foam or leave it free floating?
Any gotchas in this?

In General questions | Asked By tim brown | Jun 29 15
2 Answers

Choosing a solar (PV) system

Hi, I am completely new to solar and considering proposals from a couple of contractors.

One is proposing a 3.1 kW system of (9) 345W SunPower panels with a SunnyBoy inverter located on a south facing roof.

The other is proposing a 4.2 kW system of (14) 305 kW LG panels with a Fronius Primo 5.0-1 inverter, with panels located on a south facing roof plus on a basically flat roof adjacent to it.

In General questions | Asked By Nancy Hartman | Jun 30 15
4 Answers

Open-air barn

We are designing an unconditioned "party barn" in Central Texas for occasional gatherings for groups of various sizes. The barn has about a 1,400 sf footprint -- 1,400 sf at the ground floor then there is a loft that is about 200 sf. We have Big Ass Fans for air movement but would like to add an attic fan to exhaust the warm air that will build up in the loft/attic space. How do we calculate the amount of CFM that the fan should be moving?

In Mechanicals | Asked By Heather Gayle Holdridge | Jun 26 15
2 Answers

Spray foam insulation in attic?

I want to insulate a walk-up attic in a 100+ year old home in climate zone 6. I need to add insulation because there is only about a foot of blown in cellulose under the floor boards in the attic. I don't want to blow in more cellulose because I am thinking about finishing the attic for more living space. I am thinking about having closed-cell spray foam insulation applied against the roof sheathing. The rafters are only 2x4s and I am thinking about firring them out two to three inches to accommodate 5-6 inches of foam.

In Energy efficiency and durability | Asked By T S | Jun 27 15
4 Answers

Closed-cell spray foam in conditioned crawl space, sill gaskets, windows, & air sealing

We have our house plans back from the designer and are getting ready to start building. I have a few separate questions:

In General questions | Asked By Michael Geoghegan | Jun 30 15
6 Answers

Trapped moisture on SIP roof

I knew SIPs were the Achilles heel of my 100% engineered house design, But because of inattention to detail, heavy rains at a critical time of my house build pushed water underneath the PVC membrane (applied on mechanically fastened DensDeck) onto my SIP. It happened the night before the adjacent wall could be spray foamed to properly seal off the membrane. Unfortunately, the spraying was later done to the walls and the underside of the SIPs without knowing there was water present.

In GBA Pro help | Asked By Edward Mallett | Jun 29 15
42 Answers

Spaceloft my only option?

Needing to get all the R value I can get in a limited space. From the cob webs you can see that this is an old house. Recently installed Cedar shakes with felt underneath over the 2x4 studs or mini rafters...
I think they call this a skip sheathing install of the cedar roof?
So, 3.5" is all we have but we'd like to get to an R50 or thereabouts in our upgrade of this 1925 built home in Climate zone 4C.
Spaceloft seems the only option. With an R10 per inch. It comes in 10 cm thickness, 0.4".

In GBA Pro help | Asked By Jan Verschuren | May 29 15
3 Answers

Re-roofing a tar and gravel home

I have a small (approx. 900sq ft.) home with a flat tar and gravel roof. I know the roof is at least 10 yrs. old and I have not experienced any issues within the house from leaks or whatnot. I have however noticed that the overhangs of the roof that stretch the perimeter of the house at 2 feet, have become soft and fairly weak when stepping on them. They also show some signs of mold on the underneath side of the sheathing. I have not noticed these problems with the portion of the roof that covers the house.

In General questions | Asked By Jared George | Jun 30 15
10 Answers

Tape exterior XPS insulation and housewrap?

Hello,

Long time follower first time poster.. I have learned so much from this site and appreciate all the knowledge you people share.

We are building a tight house in zone 6 Ontario. The wall stack from inside is as follows:

Drywall
2x3 uninsulated service wall
Membrain
2x8 stud wall filled with dense pack cellulose
Cross bracing for lateral strength
2" XPS on exterior
Tyvek WRB
Furring Strips (airgap)
Hardiboard Siding

In Green building techniques | Asked By kyle lamont | Jun 19 15
7 Answers

Did I goof badly? Metal bracket against exterior sheathing

My typical wall section on part of my house is 5" of stone, two layers of 2 1/4" EPS rigid foam, Grace waterproofing, plywood sheathing with 2x4 studs and blown fiberglass between the studs.

In Energy efficiency and durability | Asked By Gary Dick | Jun 30 15
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