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7 Answers

Attic ventilation question for Joe

I have an area above my detached garage that I am trying to finish off into an apartment. I am looking to get some input on the best way to go about venting the attic. The problem I am having is that on one side of the building the roof has a fairly steep pitch (45 degrees), and is used as the interior wall up to the ceiling height at which point it opens up to an attic. My current plan is to use furring strips and 1/4" plywood to make 2" deep vents under the roof. I was then planning to fill in the rafters under this with R21 cotton batt insulation.

In Energy efficiency and durability | Asked By Mark Schuster | May 30 13
1 Answer

Root cellar construction advice -- concrete additive?

Hello! This summer we are building a greenhouse addition with an underground root cellar attached. In one of the root cellar books I read, they recommend Everdure Caltite as an additive in concrete to make the foundation waterproof. What are your recommendations?

In Green products and materials | Asked By Leah Marshquist | May 31 13
5 Answers

Any problems associated with having 1/2" plywood for engineered stone on top of 1X4 furring strips/foam?

Currently have 2X4 stud wall with cedar siding on OSB/plywood in zone 4A. Planned to remove cedar lap siding, wrap house sheathing. Install 4" rigid foam. Use either 1X4 furring strips over properly sealed foam or 3/4" thick furring strips cut from treated plywood. Then install treated 1/2" plywood for lath and scratch coat, then installing engineered stone. And sealing stone/mortar.

In Green building techniques | Asked By Matt Tackett | May 31 13
13 Answers

Insulated Basement Slab Vapor Barrier Retrofit

I have insulated my basement slab with 1" expanded foam board with floating 3/4" T&G OSB biscuit joined on the ends according to the Mixed Humid Builders Guide. The walls have 2" expanded foam board. Expanded foam was chosen to allow drying to the interior. 6 months later the subfloor started cupping at the seams. Afterwards I figured out that a vapor barrier wasn't installed under the slab when the house was built, which would explain my problems.

I have been thinking about my options and have come up with 2 that I think will work.

In Energy efficiency and durability | Asked By Andrew Eckert | May 28 13
7 Answers

In search of the elusive "perfect wall" assembly

Building in climate zone 5, have read extensively on the different wall assemblies to maximize value and thermal performance. To start, the "perfect wall" would fulfill certain criteria;
- designed to allow correct "drying potential"
- would not contain mold fodder or substrate for decay organisms
- Good air and thermal performance (within reasonable cost)
- Good structural integrity and expected lifespan
- Local work force can be trusted to get it done easily
To fulfill the above I explored steel, masonry, wood stick framing, ICF etc.....

In Energy efficiency and durability | Asked By Sal Lombardo | May 29 13
5 Answers

Where should I put the foam in this roof?

Zone 4 marine. I'm pondering insulation strategies for cathedral ceilings.

In the past we have used typical cardboard baffles and either batts or blown in FG. Recently we did a small project where we cut and fit 2" polyiso for the baffles, with the usual 1" vent space above and foamed the edges, my theory being that this will reduce wind-washing of the fiber insulation and improve air-leakage performance. We also did one with 6" of solid polyiso where there was only 2x8 rafter space available.

In General questions | Asked By David Meiland | May 22 13
4 Answers

Is the aging of urethane foams considered off-gassing?

So I'm a bit confused here. My understanding of urethane foams (e.g. closed cell spray foam or polyiso) is that the blowing agent gases trapped within the closed cell structure slowly leak out over time and is replaced with air, depreciating the R-value. But then I see that certain companies advertise that their polyurethane spray foam products/kits do not off-gas. Is the leakage of the blowing agent not off-gassing, or is the manufacturer making a false claim? I'm assuming that they use an HFC blowing agent. Maybe I'm just missing something.

In Green products and materials | Asked By Mike LaCrosse | May 31 13
7 Answers

I had solar panels installed and would like to eliminate my oil burner and use electric to heat the water for the baseboard

Was thinking of heating with a 50+ gal electric water heater or on demand. Not sure if this is the best option. Electric is not an issue because of the solar panels, just not sure if a water heater will be hot enough and keep up.

In General questions | Asked By Ed Stewart | May 29 13
9 Answers

What is an optimal HVAC strategy?

I continue to plan for my new home (Zone 3) and am now focusing on the HVAC system. Here is what I think I understand at this point. Let me know if I am off base.

- Local code usually requires Manual J, but individual inspectors may or may not ask for evidence of one to issue a COO.
- Most contractors do not perform Manual J calculations correctly, if at all.
- A third-party HVAC designer is more likely to provide an accurate Manual J (at a cost of .50 to .75 per square foot).

In Mechanicals | Asked By Steven Knapp | May 29 13
6 Answers

2 questions for Martin or anyone else who knows

1. I've just become aware of a manufacturer's claim that radiant barriers can lose effectiveness over time, either from oxidation or other deterioration. Is this true? If so, do there exist any sheet products that you believe would remain effective indefinitely in typical deep south attic temperatures?

2. I enjoyed your water heater article in the current issue of FH. Which of the steel tank models you evaluated have an easily-replaceable anode rod?

Thanks very much.

In Energy efficiency and durability | Asked By charles CAMPBELL | May 26 13
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