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1 Answer

2012 IECC - Slab-on-grade Zone 4B

I will have an ICF stem wall that will transition into the ICF house wall. The interior will be a slab-on-grade design. This is for a Zone 4B (desert) climate.

1 - Should the vapor barrier be on-top or below the rigid EPS?
2 - What thickness is good for a vapor barrier?
3 - Will 3" of rigid EPS suffice for a Zone 4B climate?
4 - Any links to some details showing the above condition?
5 - Should crushed & compacted rock be used below the EPS and concrete slab?

In Green building techniques | Asked By Peter L | Apr 8 14
1 Answer

New construction sealed crawlspace R-value and air exchange question

In climate zone 2 what is the required R value if doing sealed crawlspace and insulating foundation walls instead of floor? Table N1102.1 lists crawlspace walls. Is this for sealed and when not insulating the floor? That value is 0 for my climate zone. Is that accurate or is that for vented?

2nd question:
Should an air exchange (in addition to air supply to crawlspace) be installed in the above scenario? I think the code asks for it but I read somewhere (possibly on here) that the positives are outweighed by the negatives. Is that true? Is it preferable to not install that?

In Building Code Questions | Asked By Chris Purvis | Apr 7 14
4 Answers

The most value-engineered siding furring strips over thick rigid foam... but what width?

Assuming labor is free, I've found that the cheapest furring strips would be 15/32" plywood. It's quite a bit cheaper than 1x4's (less than half the price, close to a third, if ripped to 2.5"), and can be narrower than 3.5" without worrying about splitting like 1x3's or 1x2's would. Also, it just barely meets the 7/16" penetration requirement that James Hardie has.

In Green building techniques | Asked By Nick Welch | Apr 4 14
24 Answers

Are code-breaking BPI builders causing trouble for unvented roofs?

I have a flat unvented roof on my 100-yr old rowhouse in Philadelphia, climate zone 4. There is about 18" between the top of the ceiling and the bottom of the roofdeck. I'm looking at my options for air sealing and insulating this roof--there is currently no insulation at all.

In Building Code Questions | Asked By Andrew Levitt | May 4 11
3 Answers

Can we drywall over an interior chimney?

We had a new roof installed and it leaked around the chimney, into our attic then seeped down into our hallway. Plaster covers the interior chimney. We have no fireplace, just a gas furnace and water heater. We plan on replacing all of the walls (which are plaster, also), with drywall. We're just not certain about the chimney. The chimney is new also and has no liner. The company the built the new chimney said we didn't need a liner since there is no fireplace. Any suggestions would be appreciated. Thank you.

In Interior design | Asked By Becky Gaston | Apr 6 14
26 Answers

The "Why" in Green Building

This site excels in the "how" of green Building techniques, but it appears to me that when things move towards explaining the "why" discussions seem to move onto much shakier ground. Especially if the economic arguments don't seem to add up, rationalizations veer towards more general "It's the right thing to do" or "I want to be part of the solution" type responses.

In General questions | Asked By Malcolm Taylor | Mar 29 14
1 Answer

Web location showing how to blow cellulose from start to finish?

I am putting up a 1.5 story 24 x 24 garage. I want to use blown cellulose on the upper floor. I'd like to do it myself but I can't find a tutorial that shows start to finish steps including setting up proper ventilation.

Does anyone know if a web resource exists that can show me the step by step process ?

Thanks !

In Green building techniques | Asked By CHris Vidal | Apr 7 14
3 Answers

Plywood faced walls in insulated basement?

I"m insulating my basemen with 1" of XPS glued to poured concrete walls and 2x4 wood framed walls within with R-15 Roxul in the stud bays. I've been facing the walls with mold resistant drywall and latex paint. The basement seems relatively dry with no liquid water leaks. However, based on humidity levels I'm assuming some water is making its way in through the concrete walls and floors.

In Green building techniques | Asked By Andrew Alden | Apr 4 14
1 Answer

Best method for insulating attic roof rafters?

I am finishing my attic for living space. The walls are 5ft up then 3ft diagonal then 8ft flat. (see photo). The kneewall and ceiling are getting r30. What is the best way to get a high r-vaule in the 3ft diagonal that contacts the roof with such a small depth? Ventilation is not going through it.

In General questions | Asked By Matt Edwards | Apr 6 14
1 Answer

How to best add insulation to sheltered exterior wall?

Having recently moved into a large, 1980s-built home in central Maine (read: cold) I'm in the process of improving air sealing and insulation. The home has a large attached garage with a non-insulated second floor, and an adjoining second floor room that was framed and insulated but never finished or heated. It's not clear how or where the builder intended to access this space it from the finished second floor but I don't need the space anyway.

In Green building techniques | Asked By Nick Lambert | Apr 6 14
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