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7 Answers

Plastic pipes/ hot water tank - leaching chemicals....

Scientists say plastic chemicals leach into the heated water.
Some people choose not to believe it; perhaps because they sell or work with it - i dont know.
I prefer to stay on the careful side.
I have a hormone imbalance due to plastic chemicals found in my blood, causing me major health problems which started when all our pipes got changed over to plastic.
My water was tested and found to have much higher levels of "poly-chemicals" than non -plastic plumbed water.

My pipes are plastic, and my hot water tank is glass inside, but the tubes going in are plastic.

In Green products and materials | Asked By Lisa Walters | Feb 29 12
32 Answers

Insulating miners’ containers - Ulaanbaatar, Mongolia

Andy lives in Ulaanbaatar, Mongolia, the coldest capital in the world. Right now night time temperatures are hitting -40 F and C. He is an ecologist, fly fishing guide, and now learning green building / energy efficient building / sustainable design. He is doing some work with a local construction firm and is trying to figure out better building methods for his climate.

In Energy efficiency and durability | Asked By albert rooks | Feb 13 12
1 Answer

To insulate or not...

I just move to Florida from Massachusetts. The house has 3 inches of rock wool in the attic. There is no insulation over the garage space which is part of the house. Two of the garage cinder block walls are adjacent to the house making up two interior walls. One of those walls has a door to enter the house. Knowing I needed more insulation in the attic, I took advantage of Tampa Electric's energy aduit. The energy analyst agreed that the attic needed additional insulation, and they provide you with a coupon to help defray the cost.

In Energy efficiency and durability | Asked By Joe Pakus | Mar 1 12
6 Answers

How to properly insulate an unvented cathedral ceiling

In your recent "Musings of..." you refer to an unvented roof assembly as follows:

"The 2009 IRC (Section R806.4) allows unvented roof assemblies insulated with a combination of rigid foam insulation above the roof sheathing and air-permeable insulation in the rafter bays. (The 2009 IRC defines air-impermeable insulation as “an insulation having an air permeance equal to or less than 0.02 L/s-m² at 75 Pa pressure differential tested according to ASTM E 2178 or E 283.” Although spray foam insulation and rigid foam insulation can meet this standard, dense-packed cellulose cannot.)"

In Building Code Questions | Asked By Ralph Hill | Feb 29 12
3 Answers

SIP Roof

Moisture control and permiablity in CZ 4. A client is interested in a SIP roof as a retrofit for an older log home. Currently the plan is to strip the existing roof of asphalt and felt and repair as neede the existing osb. The build out calls for 1.) 30# felt 2.) 4-6" SIP panel nail board 3.) 30# felt 4.) High albedo standiing seam metal roof. Is the first layer of felt a potential moisture collection issue, would the system be better off without it?

In Green building techniques | Asked By Bruce Glanville | Feb 29 12
8 Answers

Fireplaces in Tight Houses

We are building a custom house with SIP walls and SPF roof. Manual ventilation will be installed. Plans were originally for a 2x6 enclosure and an unvented fireplace. The research I've done says unvented fireplaces in a tight enclosure are a bad idea but the client (my wife) doesn't like the look of an exterior chimney.
Is there a way to vent a fireplace unobtrusively? Or, can I get a way with unvented gas logs if I supply make up air?

In Green products and materials | Asked By Chris Baddorf | Mar 1 12
36 Answers

Stacking SIPs and nailbase for superinsulation

I have a passive house project in the Colorado Rockies and need heaps of insulation to make the numbers work (R-90 walls, R-120 roof). A local supplier has polyurethane SIPs that come in at R 6.66 /inch, however only to a dimension of 8.25" thick for approx R-50 for the 8" panel. I had thought about stacking nailbase SIP from the same manufacturer on top to achieve my R value, but my brain sounded alarm. There would be a layer of OSB that can't "breathe"-this seems bad.

In Energy efficiency and durability | Asked By Erik Lobeck | Feb 24 12
1 Answer

Cathedral ceiling rigid foam vents?

New construction -- having the attic trusses built with 18" top chord for insulation and baffles. Not totally sold on spray foam.

The question is: doesn't building vents with foam or using plastic vents that are sealed to the truss create an area of condensation (it shouldn't condensate with that much insulation)? Or at least, in the event it did get wet, doesn't give it the ability to dry to the outside?

The drywall inside will be sealed and there is only one roof penetration design for plumbing vent.

In Energy efficiency and durability | Asked By jeff ANDERSON | Feb 29 12
1 Answer

Site upgrades going on now

Hello all,
We are in the process of adding a couple of features to GBA and tweaking some of the styles. You will likely notice a few glitches as we move code from the development servers to the live server.

You can report problems here if you wish. We should have this first phase of upgrades complete sometime tomorrow, but you never really know how things will flow.

Thank you for your patience.


In General questions | Asked By Daniel Morrison | Feb 29 12
9 Answers

Are there efficient in-slab radiant systems that also cool?

A client is getting bids from HVAC contractors to design/install heating & cooling systems for a 3100 SF single-level home located in the high desert climate of southern Utah (think Alburqurque, NM). The bids are quite high, perhaps due to the fact everyone says the client will need TWO complete systems; one to heat, one to cool. The bids all specify in-slab boiler-fed hydronic radiant heating coupled with a standard forced air furnace with a conventional AC unit for cooling (and I guess back-up heat). A friend keeps saying: "Screw that!

In Mechanicals | Asked By Timothy Smith | Feb 28 12
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