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0 Answers

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In NAHB Class Discussion | Asked By Cheryl Larkin | Dec 27 14
2 Answers

Additional insulation below laminated/floating floor over rigid-foam-insulated concrete slab?

I have a 4" concrete slab insulated with 4" of rigid foam (on the underside, of course). I was planning to install laminated floating floor on top of everything. As I have to install 2x2"s over the concrete in order to hold the laminated floor, a friend suggested to fill the space between the 2x2"s with insulation or, at least, dirt.

The questions are:

In PassivHaus | Asked By Jose Castro | Dec 27 14
6 Answers

Can this really be? ACH50 of 0.62?

With homage to Martin's Christmas poem, I thought I'd share the results of my blower door test and ask... Is this really to be believed?

The interior volume of my home, including unfinished basement, is 53,569 ft^3 as calculated in my SketchUp model of the place. The blower door test results showed 551 CFM at 50 pascals, giving an ACH50 of 0.62.

In Energy efficiency and durability | Asked By Kent Jeffery | Dec 24 14
50 Answers

Solar thermal systems for heating water

Jin this is for you and Richard

Let's run the costs and the systems through the paces

so far I hear $16,000 for a Caleffi system and maybe that for labor? $32,000
saves $500 a year

CO2 production unknown to manufacture
Very little CO2 to run the ECM circulators

There are much less costly systems

NYSERDA here in NY is unveiling a new program this January
Will post more about it when they tell us more

Jin, Richard, others... what say you all

In Mechanicals | Asked By aj builder, Upstate NY Zone 6a | Dec 15 14
2 Answers

Solar thermal buffs bite (Martin) back

Solar Thermal is Dead (NOT!)

I should start out by saying that I like a lot of the articles that Martin Holladay puts up on theGreenBuildingAdvisor.com site. They often bring out new points of view and promote some good thought and discussion on topics that don’t get addressed a lot elsewhere.

In General questions | Asked By flitch plate | Dec 23 14
1 Answer

Using sill gaskets and tar paper on the interior for interior ledgers

So I have ledgers being bolted onto the foundation wall concrete to hang the joists after.

Right now I have tar paper between the ledger and the concrete so that the concrete can breathe.

I was wondering if I would need sill gasket as well on top of the tar paper to prevent moisture transfer.


In Energy efficiency and durability | Asked By Richard Wang | Dec 24 14
3 Answers

Please help ID this loose-fill insulation

Recently did some work in an attic that contained a type of loose-fill insulation I've never seen before, and I would like to help the homeowner find out what it is. It does not look like vermiculite.

It's been poured over old fiberglass batts in this 1940's-era house; I'd guess sometime between the 1950's and 1970's. It looks for all the world like EPS beads. Lily white, about the size of peas, very consistent in size. But it sure ain't EPS. It feels like lightweight little rocks, and just disturbing it a little kicks up the most obnoxious dust.

In General questions | Asked By Andy Chappell-Dick | Dec 24 14
6 Answers

Air seal complex joint

I have a polyiso/wood and polyiso/polyiso joint that I want to air seal. So far I have been using spray foam to accomplish the task. Even with the low expanding, "flexible" window type foam, I'm not very impressed with the integrity of the seal. The foam tears somewhat easily and seems to separate with even modest amounts of force against sealed pieces. I know this problem has been covered extensively. Tapes and gaskets seem like they might be tough to use on this 3D joint complex joint. Caulking seems like it may be more robust but difficult because the gap isn't uniform.

In Green building techniques | Asked By Brian C | Dec 24 14
6 Answers

Closed-cell spray foam on roof deck... shingle underlayment choice?

Good day,

I'm planning on doing spray foam insulation on the underside of my roof deck.

I'm about to start shingling next week, and was planning on using synthetic roof paper instead of tar paper.

Then I read an article saying that on unvented roof assemblies (what this will be), most synthetic roof underlayments should NOT be used.

I did some digging, and the product I had planned to use called "Rhinoroof" has a perm rating of 0.5, aka it would create a vapor sandwich between my shingles and under deck roof insulation.


In General questions | Asked By Mark Helmrich | Dec 19 14
7 Answers

Sprayfoam house and real stone cladding. Wall sheathing?

Good day,

This is my first post, but I want to comment how much I've enjoyed reading topics on this q&a forum.

My question is regarding a new house I'm building. Zone 8 climate (cold!) similar to Alaska, 2x6 framing 16" OC walls, 1/2" OSB sheathing, no basement. Right now I'm just finishing up framing.

I've been dead set on using closed cell spray foam all around...on the interior wall cavity at 3" thick, 4" on the roof deck and 1.5" on the floor.

In General questions | Asked By Mark Helmrich | Dec 15 14
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