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14 Answers

Is an HRV/ERV system necessary?

My husband and I are building on our own a small house that we've tried to make as green as possible. Neither of us are familiar with green building (he's conventional framer) and we rely on this website and green building books to answer our questions. The one thing I'm stuck on is, do we need to have an HRV or ERV system? We are building the house as tight as possible, sealing all leaks, and have an inch of rigid foam on the exterior and will have R-21 cellulose interior insulation. The house is 24x24, two floors and an unfinished basement.

In GBA Pro help | Asked By Morgan Clark | Nov 27 12
5 Answers

Tape vs. mastic

I'm posting this under both Energy Efficiency and Mechanicals, in the hope of catching more flak.
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"Reputable" duct sealers all swear by mastic, but a good "duct tape", e.g., Nashua 322 or 324a seems adequate to the task at hand. 324a has an application temp from -10 to 200ºF and a max temp of 325ºF. Even 322 is good for a max temp of 200ºF. I hope my ducts aren't getting that hot.

In Energy efficiency and durability | Asked By Robert Fankhauser | Dec 19 12
2 Answers

Basement insulation/ventilation query

Finishing our older Seattle home's basement and have run in to some unusual situations regarding insulating and venting the space.

In Green building techniques | Asked By Brian Wendorf | Dec 19 12
5 Answers

Using Fiberglass Rebar

HI, I was wondering if anyone has knowledge on using fiberglass rebar in the walls of an ICF house? I am interested in this as it would lower the electrical and magnetic conductivity. I am sensitive to EMF's . Here is one such product. http://www.fiberglassrebar.com/why_composites.htm

In Green building techniques | Asked By Kami Kline | Dec 18 12
2 Answers

Can I use my electric furnace fan to move heat from my wood stove?

I have a 2000 SF home (approx 1000 foot each level, lower is "daylight" meaning one side is underground on the lower level and one side of the lower level is entirely open). I have two Blaze King wood stoves (catalytic converters) on each level but my thermostat for my furnance is on the main level. If I use my wood stove upstairs I don't heat my downstairs (where all my water piipes are) and if I use my downstairs wood stove it won't heat the upper part of the house.

In General questions | Asked By ann greene | Dec 15 12
13 Answers

Air Sealing Roof Retrofit

We are in the beginning phase of repairing & renovating a 100 year old wood frame church in Somerville, MA.

We are considering our options to substantially improve the energy performance including upgrading the exterior envelope and overhauling and/or replacing mechanical systems. This will be a long process, maybe over 10 years. However, we need to replace the roofing immediately. We are going to remove the existing asphalt shingle roofing down to the sheathing and install new asphalt shingle roofing. The roofer has proposed Grace Tri-flex synthetic underlayment.

In Green building techniques | Asked By Nathaniel May | Dec 17 12
6 Answers

Is this too much door sill cantilever?

I've got a thick siding profile, so my door sill is going to cantilever out 5-6" past the framing.
I'm not sure how to best anchor a stone, or hardwood sill considering the potential weight of foot traffic.
I could pour a concrete sill over anchors epoxied into the stem wall, but it may look weird.

Those with exterior foam walls and rainscreens might run into a similar issue?

I've got:
2x6 wall
1" sheathing
1" furring
2" thick clapboard profile
1" trim (installed over claps)

In Green building techniques | Asked By Richard Baumgarten | Dec 18 12
7 Answers

Best tape to use on EPS foam around windows (Protecto Wrap?)

Working on my ICF home and getting near setting windows. I was thinking I would use the Protecto Wrap (BT25XL) however it is getting cold, and looking at the product specs it calls for 45 degree temps to install, which we will be below. So I was looking into the Super Stick product and it can go down to below 0. However I can not find if it can be used on EPS foam or sticks well. I would assume if it did, it would mention it as does the BT25XL.

In Energy efficiency and durability | Asked By Jesse Lizer | Dec 12 12
8 Answers

Air seal existing house

I recently bought a house in Northern Virginia (Zone 4). The house was built in 1982 and is all electric with heatpump.
Since moving in I have had the roof fixed/replaced (no ventilation originally and exhaust fans terminating in the attic = lots of moisture damage), replaced the bathroom fans with Broan fans that have programmable Z-wave controllers to provide continuous exhaust ventilation (and terminates outside the house with 6" ducts), air sealed the attic, and added cellulose insulation to the attic.

In General questions | Asked By Francois Strydom | Dec 14 12
1 Answer

How should I fill in space between a slab floor and the perimeter walls?

The floor has radiant coils and insulation underneath but the perimeter was not insulated when the slab was poured. We cut a trough (1.5" wide) and now want to fill it with insulation. Any suggestions on how to do this? The house is in the Northeast and is essentially sitting on dry sand.

In Energy efficiency and durability | Asked By Molly PIckett | Dec 17 12
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