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7 Answers

Closed-cell spray foam versus dense-packed cellulose - Noise control in a PassivHaus

This is a comment rather than a question.

In our pre-certified PassivHaus in northern NJ, we have 10-inches of densepack cellulose and 2-inches EPS in the walls, and 10-inches of closed-cell spray foam in the roof.

We've noticed that the noise attenuation through the walls is much greater than through the roof.

Most of the noise getting into the attic comes through the roof, which is asphalt shingle over plywood decking on 2x12 rafters, with the space between the rafters filled with 10-inches of the closed-cell spray foam.

In PassivHaus | Asked By Len Moskowitz | Oct 15 14
12 Answers

Curbless shower with a PVC liner -- how to terminate the liner at the floor?

I'm installing a curbless shower----Concrete slab-on-grade with a sump for shower.
Using traditional method for shower floor---PVC liner, with pre-slope and top slope mud beds.
2x2 tile on shower floor and 18x18 travertine on bathroom floor.

My question is how to handle the waterproofing interface between my sump and the bathroom floor level (like where the curb would have been).

In General questions | Asked By john walls | Oct 19 14
5 Answers

An outside, completely isolated, balcony column structure

In an outside, completely isolated, balcony column structure that must be finished in stucco and built using steel studs, would it be possible for any moisture damage in the inside of it if we were able to completely seal the inside from the elements? In a 4c zone, applying stucco to acrylic panels to make a stand-alone column.

In General questions | Asked By peter mare | Oct 20 14
2 Answers

Gluing rigid insulation to interior of roof sheathing

My home is in Northern Michigan and I wish to insulate an attic that has storage trusses and considerable open spaces behind the perpendicuilar truss members. There is soffit venting around the entire attic perimeter. The attic floor is insulated to R 30. (Peaked roof built over original flat roof)

My first choice was to spray polyurethane to the cathedral underside of the roof sheathing, however I am having difficulty scheduling a contractor, most of whom have bigger jobs they are chasing, so I am considering other options.

In General questions | Asked By Wes Benner | Oct 22 14
2 Answers

Insulation of the interior stem wall

I am building a 40x60 metal workshop. It is slab-on-grade and I had specified 2" rigid foam on the interior of the stub wall, thus creating a thermal bridge between the foundation and the slab. The footing and stem wall have just been poured. I think there has been a mis-connect between my contractor and myself because it looks like he is going to place 2" thick rigid foam only in the space between the footing and the slab (i.e. the 4" slab will be "faced" with 2" thick rigid foam...

In Energy efficiency and durability | Asked By ron marsh | Oct 22 14
12 Answers

Thermal energy storage

~3900 square foot house.

I am thinking of building a water based TES tank using ICF in a crawl space.

The plan would be to use RV antifreeze in an active (pump) circulating heat exchanger that sits at the bottom of a tank of water. Domestic water supply would pass through another heat exchanger that sits at the top (for stratified water column effects) inside this tank and preheat water for radiant hydronic boiler and domestic hot water.

I was thinking 12'x12' @ 6' tall for a 864 cubic foot / 6463 gallon tank.

In Green building techniques | Asked By Jim Pancanke | Oct 21 14
4 Answers

Insulation dew points and archaic insulation

I have a couple of questions, both somewhat academic since there may be little to do about them.

I live in a 1938 1.5 story (Cape-style) house in St. Paul, zone 6. About 3 years ago the shoddily-added back porch was falling apart and the roof shingles were shot , so I tackled both in one, replacing the back of the house with a new addition, and re-roofing the entire house using this "cold roof" article in JLC as a model (in short, adds 3" XPS foam plus 1-1/2" air gap above the original roof): http://www.jlconline.com/rooftop-accessories/retrofitting-an-insulated-c...

In GBA Pro help | Asked By Graham Allan | Oct 20 14
4 Answers

PERSIST vs REMOTE vs SIP ?

We are building a new house in MN (6b), considering various wall systems, and trying to get a handle on the pros and cons of each. Thus far we have:

SIP Pros
- Better known construction method, easier to find carpenters, ...
- Well documented construction details

PERSIST Pros
- Seems like it would be easier construction than SIP.
- Easier to get all details correct.
- Provides significant interior space in attic for ducting, extra room, storage areas, etc.
- Chemical elements (foam, osb, etc) on outside of air/vapor barrier

REMOTE Pros

In Green building techniques | Asked By Walker Angell | Oct 21 14
9 Answers

“Air-sealed” can light retrofit vs. Tenmat cover in attic?

I’m planning some air sealing work in my attic. I’ve got a bunch of recessed can lights to deal with, and I had been planning to use Tenmat rock wool light covers on the attic side. This would involve caulking (say, Tremco acoustical sealant) or foaming to seal the Tenmat cover, plus taping up any cuts to allow for electrical wires, etc. After first going into attic, pulling back existing insulation, sweeping the area clean, etc.

In Energy efficiency and durability | Asked By andrew c | Jun 22 14
2 Answers

Mold in crawlspace

I live in Gadsden Al,and we purchased a home and for a couple years its been smelling old,i went under the house and found the mold on the west wall where the flower planter is outside the house and by the pipes coming from the bathroom. I fogged the crawlspace very well with corcodium and I no I have to clean the walls too. But I need to bring the height of my front yard up 1 ft and at a slant to stop the water from ever going back under the house.the flower planter is 11/2 ft high and 12ft long 11/2 ft wide. and has brick on the outside.

In GBA Pro help | Asked By weldon jones | Oct 21 14
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