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4 Answers

How to seal 4" EPS foam at slab edge (radon concerns)?

Basement concrete 4" slab to be poured on top of 10mil poly, 4" EPS (2 layers staggered seams), and gravel at bottom with perimeter drains connected to vertical radon vent pipe. Building in a high radon zone, will the poly be sufficient covering the 4"x4" foam perimeter strips not covered by concrete at the slab edge? Should I be tapering the foam edge instead of keeping the full width of 4"x4" strips?

Asked By e c | Oct 29 14
1 Answer

Foundation sealing options?

The foundation under my ca 1870s house consists of new and old concrete under the ell, granite blocks under the main house, and a ‘rubble’ wall between the two. A concrete block wall was constructed within a small portion of the granite foundation. This little ‘hallway’ (which has a poured concrete floor) provides access to the breaker box and a small window frame that links the crawlspace under the main house and the (almost) full height basement under the ell. There is a drain beneath the dirt floor of the ell, covered by plastic and rock.

Asked By Rob Shuman | Oct 30 14
1 Answer

I am considering a double wall construction

I am planning to build a house in Charleston, SC (Hot -Humid Climate) and would like to get as close to Net Zero as possible. I think mini-splits will work but dont know if double wall construction is the way to go. Any help would be appreciated.

Asked By Rick Fetter | Oct 30 14
7 Answers

R-35 wall assembly for a 4C Marine climate zone

I am about to build on a 85" rainfall, 6000 HDD and no cooling system (I can withstand a little heat in summer)

I'm thinking of (from outside in)
* 1" wood siding
* 1" of air gap with 1x3" furring
* asphalt paper as WRB and air barrier
* 3" 2pcf EPS as R10 sheathing,
* A 10" double frame wall filled with a total * of R-24 polyester insulation
* asphalt paper as air barrier and vapor retarder
* 3-4" interior wood finish

(see attached image)

Asked By Jose Castro | Oct 29 14
3 Answers

New siding/windows and rigid insulation - need some advice

We have a 46 year old house that we have renovated extensively inside and are now planning a major exterior renovation for the spring. We live in Newfoundland, Canada and are in Zone 6.

Asked By Chris Stoodley | Oct 29 14
6 Answers

100-year-old single-pane windows, storm windows with low-e, or interior panels?

1. Is Low-E a good choice for all windows, or should it be selected for certain windows according to their location?

2. Is there any unbiased performance data available for storm windows? In particular Larson windows? I have found an interior panel (link below) that claims a U-value of .29 and has achieved Energy Star recognition. Can a Single pane, low-e storm window do a better job? I think it's worth noting that a single pane storm being mounted on the outside of a 100 year old window frame may reduce drafts entering the window frame area more than an interior panel.

Asked By b l | Oct 29 14
4 Answers

Climate Zone 6: Low-slope warm roof materials / assembly

I am designing a large mono-pitch shed roof in Climate Z6. The slope is 1.5 in 12 or about 7 degrees. A ventilation space seems impossible due to the scale of this roof plane. 60 feet sloping up and about 25 feet wide. I would like the finished roofing to be standing seam metal as the roof is visible from various vantage points on the property.

It my understanding that we will need to install a high-temp waterproof membrane like Grace Ultra over the entire roof sheathing to prevents leaks. This means the roof assembly is only able to dry to the inside.

Asked By Meri Tepper | Oct 29 14
35 Answers

Seeking an air-to-water heat pump

I'm looking for an air-to-water heat pump and feedback from those who've used them. We have a LEED for Homes project in Victoria, BC, perfect climate for heat pump, affordability of project prohibits groundsource for 36Kbtu heat loss of 1800 ft2 home and for optimal comfort, low temp/efficiency, to avoid ducting we're selected hydronic in-slab for heating distribution thus standard air-to-air heat pump is a no-go.

Asked By Allison Ashcroft | Jul 28 09
1 Answer


I recently purchased a 1930's brick and aluminum-sided two-family home in Teaneck, NJ. The insulation in the upstairs apartment is very old and dilapidated and lining the roof. The outside walls in both apartments are not insulated, it would seem. I would like some ideas about insulation. Can call me, too, 646-245-3801.



Asked By Janice Thill | Oct 29 14
5 Answers

Want to reduce indoor humidity in a cool, humid environment. Outdoor humidity >70% most of the year. Would an ERV be useful?

I live in a fairly new, well sealed house on the west coast of Canada. Ventilating indoor moisture most of the year is difficult as the outdoor humidity rarely goes below 50% and in spring and fall, usually in the 80-90% range, with temperatures averaging 40-60 F. I am researching ERVs, but unless they can reduce the humidity of the incoming air significantly, ventilation is only going to increase indoor humidity. Lots of condensation on the windows during fall, winter and spring. Air quality in the house is good.

Asked By Bill Readings | Oct 26 14
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