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17 Answers

Floor insulation, Roxul vs closed foam

The foundation of my house (1152 sq/ft) is post and pier and there is no perimeter enclosure.
The bottom of the 2x8 floor joists are about 40" from the ground.

I am considering two methods of insulation.

The first method is 7.25" thick Roxul batts (R30) that are covered with 7/16" OSB sheets.

The second method is 1.5" (R10) of sprayed closed cell foam.

The cost to me of both methods (if I don't count my labor with the Roxul) is nearly identical, about $2000.

The Roxul has the advantage of about 3x the R value of the foam.

In General questions | Asked By Jim Wright | May 14 14
7 Answers

Insulating a sloped wall & attic

We're renovating a 2.5-story 1924 brick house in Brooklyn (right at the line of zones 4A and 5A). For historic and budgetary reasons, we're not gutting the place. Instead, we're trying to insulate/air-seal/tighten where we can maximize environmental impact and minimize sledgehammer impact. Something along the lines of the "Pretty Good [Retrofitted] House."

In Energy efficiency and durability | Asked By Kimberly Howell | May 19 14
3 Answers

Locating ducts in attic underneath a thick layer of cellulose

Building a two story house with basement in climate zone 5A. Attached to the "main" portion of the house is a one story "wing" with a laundry/mudroom and the garage (this portion is built on slab...insulated with EPS to ~R-22). Walls are R-48. Raised heel (16") trusses in the attic with blown cellulose to at least R-60.

My plan was originally to keep all ductwork to the slab "wing" inside the conditioned envelope and soffit around the ducts.

In General questions | Asked By Robert Kohaus | May 20 14
3 Answers

Warmfloor versus hydronic heating set in gypcrete or Maxxon Therma-flor?

I'm an architect in WA. A client is building a new home in Eureka, CA. I had specified hydronic radiant heating set in a Maxxon Therma-Floor (similar to gypcrete) base. There is no supplier in the Eureka area. Apparently it comes out of Santa Rosa or Sacramento. The owner and contractor are now thinking about using Warmfloor (electric radiant heating). I have heard that the heat fluctuates more with Warmfloor because there is no mass. Does anyone have experience with Warmfloor? or any suggestions about gypcrete supplier/installer for the Eureka area?

In General questions | Asked By Karla Forsbeck | May 16 14
4 Answers

Minisplit install questions

I am building a new house and planning to install a couple of minisplits. The air handler locations are going to be approximately 20' away from the outside condenser and located on interior walls. I am planning on bringing drains to these locations but my question is what size conduit should I run under the slab to accommodate the copper lines and electrical. I would also like to rough in conduit for another potential mini split down the road so is 2" large enough or would 4" be more appropriate.

In General questions | Asked By kye ford | May 18 14
0 Answers

Fix a water leak between porch and house

I have a poured concrete porch that also serves as a roof for a basement storage room. When the builder proposed creating this space, I had reservations but he "did them all the time and they never leaked." Even so, I asked the him to include a roofing membrane that would extend from the house wrap (spanning the joint between the slab and house) and under the slab out to its edge. I thought the sub had completed this step, but it's now apparent that he did not. I now have a slow drip into the storage room whenever it rains.

In GBA Pro help | Asked By Steve Knapp | May 19 14
6 Answers

Has anyone tested charcoal furnace filters to see if they have an appreciable benefit in indoor air quality?

In commercial settings charcoal filters have been used for years to help eliminate odors and harmful gas particles. While I don't understand the science behind them, charcoal filters attract small gas molecules that would otherwise pass through even a Hepa filter.

I don't know how effective the furnace filters would be, as they can't be overly thick, but I would presume it might work to capture some of the off-gassing polutants? Cartridge style respirators use a rather thin filter and are effective, so who knows.

In Green products and materials | Asked By Rick Van Handel | Apr 28 14
2 Answers

When Cellulose Insulation is subjected to moisture or disturbed after being blown in, how is it affected?

We hired a contractor in Canada to replace insulation in our attic when a roof patch opened up under an ice dam in 2011. They removed batt insulation and replaced it with blown in cellulose fibre insulation. When they blew in cellulose insulation they did not connect the new bathroom vent hoses they supplied or seal pot lights below the vapour barrier and this is an extreme winter weather climate. This spring, the insulation was disturbed in order to determine the source of water causing damage to the drywall in the room beneath this space.

In GBA Pro help | Asked By Susan Bly | May 19 14
15 Answers

Using insulation board on top of OSB and under siding

I have a 1500 square foot house with a 500 square foot bonus room upstairs. I have a downstairs window that is broken and I need to replace. It is a vinyle window with a nailing flange.

I live in southern Kentucky (42206). My house has 2x4 walls with fiberglass batts in all walls including the interior walls.

I have osb outside walls with no tyvec or anything on them. Nailed directly to the osb is vinyle siding.

In General questions | Asked By don gilbert | May 15 14
1 Answer

Energy efficient heating and cooling questions

My house was built around 1998. I have the same split system heating/air conditioner with propane heat and water heater.

My system works fine. I actually prefer a propane water heater with a family of four because it can keep up better and still works during a power outage. (I live in the country)

I am wanting to reduce as much as possible utility costs. I was debating installing a more efficient unit myself.

In General questions | Asked By don gilbert | May 19 14
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