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8 Answers

EPS Foam on Exterior with interior vapor barrier?

I am gong to be re-siding my house (cedar) and am considering adding 1" or 1.5" of EPS foam on the exterior. My concern is that the current R13 insulation (2x4 walls) has a kraft faced vapor barrier. I know that I can't use XPS foam on the exterior because it is impermeable, but I know that EPS has a higher permeability, so I was hopring this would work and allow drying to the outside. I will be using a rainscreen over the foam. I am in Portland, OR which is in zone 4.

Would this work? Is it even worth adding the foam to an R13 wall?

In Green building techniques | Asked By David Fischer | Mar 10 12
20 Answers

Foam Under Monolithic Slab/Footing

Inspired by a recent blog post by Martin, I'm wondering if anyone has attempted to form and pour a monolithic slab/footing with foam at every facet, as depicted in the section sketch below. Pieces A and E are straightforward enough. Piece B calls for a lot of fussy smoothing at the bottom of the trench. Piece C looks like a serious pain in the neck to fit and hold in place. Piece D is a fantasy.

In Green building techniques | Asked By Ray Sten | Mar 15 12
14 Answers

Please review our double Stud Wall over floating slab plan

Since it will be a couple of weeks before GBA posts a recommended wall section, I would like to get your critique of the wall section and foundation plan drawn by my architect. We are still in the early stages of design but have a tight timeline to get the house designed and started.

Thank you

In GBA Pro help | Asked By Elizabeth Kormos | Mar 16 12
1 Answer

I am looking for a listing of ICC accredited labs who are experienced in testing housewrap material for R-value

I am new to the building construction industry and have found a product that I think can improve insulation characteristics. I understand for it to be used it must be tested by an ICC accredited laboratory. Their listing has thousands and thousands of accredited labs but they do not list them by product category. I'm asking if anyone can direct me specifically to one that could help me get this product tested.

In General questions | Asked By David Bechtol | Mar 22 12
1 Answer

Are there different conditions when to use low-e interior versus exterior reflective windows?

The reflection from my neighbor's low-e window is melting the siding on my house. I have heard that it would make a difference if the south side of his home had interior reflecting windows rather than exterior reflecting windows. Is that true? We live in Connecticut so we obviously experience warm temperatures in the summer and cold temperatures in the winter.

In General questions | Asked By MaryAnn Brown | Mar 21 12
3 Answers

Sill gasket

I'm currently planning on using an EDPM gasket under my sill plate (new construction). I'm also planning on using sprayed close cell to fill/seal the rim joist on the basement side. Since the main purpose of the sill gasket is air-sealing, is it really necessary if I do a quality job with the closed sell spray?

In GBA Pro help | Asked By Jim Orasky | Mar 21 12
7 Answers

Board foam insulation under an unvented cathedral roof

Hi, We are building a passive solar house near Knoxville, TN (zone 4). The house is in the dry with a "cool color" asphalt shingle roof already on. We are getting ready to insulate.

The walls are from the outside: Hardie, 3/4" rain screen, Tyvek, 1 1/2" strapping with ESP insulation in between, OSB, and 2x6 walls 24" oc. We are planning on using dense pack cellulose in the walls with air tight drywall. This seems OK to us.

In Energy efficiency and durability | Asked By Ken Morton | Mar 14 12
9 Answers

Whole House Dehumidifier - Is it worth while?

I'm building a new home in Climate zone 6 (central PA). It will be well insulated and air sealed. While I'm still wrestling with the ERV vs dedicated bath exhaust fan decision, my HVAC contractor has just further muddied the water. We are going with a closed loop geothermal heat pump. He has recommended we install a whole house dehumidification system (with outside air capability). Specifically he recommends installing a Honeywell DR90. In theory this makes sense for those days that are not hot, but still humid. Any thoughts or opinions? Is it worth the net installed cost, $1400 net.

In Energy efficiency and durability | Asked By Jim Orasky | Mar 16 12
10 Answers

What can I cover my exterior foundation insulation with?

I have 2 layers of 1.5" XPS with staggered seams glued to a damp-proof block wall. The exposed wall ranges from 6" to 2' above grade. I saw the article with some suggestions for protection like SBC and protecto wrap, but wondered if I could use vertical vinyl siding. I will use a termite shield and drip edge over the foundation covering, and I have the foam covered with roll roofing down to the footer (30" below grade). I was also considering stone veneer but was worried about how to attach it.

In General questions | Asked By Matt Black | Mar 19 12
4 Answers

Is duct sealing considered part of infiltration measures in older homes?

The basic scenario is in a older home when you seal the ducts it causes infiltration numbers of the blower to drop significantly. By code would you count that to the infiltration measures or keep it separate. And if you keep it separate what would be the right way of running the test and completing the work.
Thank you very much

In Building Code Questions | Asked By Adrian Loza | Mar 19 12
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