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4 Answers

Radon Gas Piping - number of holes or pattern required?

Is there a standard or code for the number and pattern of holes required for a new radon system?

In General questions | Asked By RUSS CROUCH | Nov 6 14
4 Answers

HVAC question: tiny DC fans

Hi, all,

You may remember me from my 120sf outbuilding threads. About that outbuilding:

I've been looking at low CFM quiet DC fans such as the Panasonic Whisper series, the Broan ones, etc. What I've learned over the past couple of years is that there are very few that run down to 10CFM (basically, the Panasonic ERV does) which is the correct size for the space in question.

In General questions | Asked By Minneapolis Disaster, 6B | Nov 6 14
11 Answers

Metal roof & underlayment (AquaGuard - DryTech)

Curious to see if anyone has used or seen the product called "AquaGuard Dry-Tech"?

It's designed to allow airflow underneath a metal roof to drain any condensation that can form under the metal roof and it also provides an acoustical reduction in metal roof noise.

The bottom of the underlayment is NOT breathable/non-permeable and this attaches via peel & stick to the roof sheathing (OSB SIPs).

In General questions | Asked By Peter L | Nov 3 14
12 Answers

Drywall directly on stem wall

I've got a 1' tall stem wall in my current design for a house, the outside of the stem wall is insulated with 6" of XPS and will have a moisture barrier on the stem wall. The slab has 3" XPS underneath.

I'm wondering if I should build the walls flush with the inside edge of the stem wall, and then run the drywall all the way down over the stem wall- attaching with glue?

Or is it better to make the drywall end at the stem wall and paint that last 1' of concrete, in case of moisture?



In General questions | Asked By Tom Frisch | Oct 30 14
2 Answers

Longevity of valves on PEX manifolds

I am planning on a home run installation in a new house. I never had much luck with the PVC valves currently used in residential plumbing actually working when you need them to.. They either are stuck open or will not shut off. I would try exercising them to keep them loose but they would end up leaking past the stem.

I am concerned with the poly valves used on the manifolds not doing there job 10-15 years down the road. Some manifolds offer the optional copper or brass valves, but our water has a high content of limestone and is tough on copper pipes and fittings.

In General questions | Asked By John H. Stehman | Nov 5 14
8 Answers

Sealing meeting point of brick wall and asphalt driveway


My house, a semi-detached, has an asphalt mutual drive between it and the neighbors house to the south that comes right up to the side of the house.

I'm concerned about the meeting point between the asphalt and the brick as it looks like water can collect there and seep into the brick (I have some Interior spalling and suspect that this is the source), but I'm not sure how to address this.

Do I use caulk.. or something with the consistency of tar.. or something like mortar for bricks..?

Some photos here:

In General questions | Asked By Jon Haque | Oct 22 14
3 Answers

Hybrid vented and unvented roof/attic

I'm working on a small renovation to the second floor/attic of old house in climate zone 5. A gable roof with basic dormers on each side. In short, the finished ceiling will follow the pitched roof (cathedral style) for about half the length of the rafters and then transition to a flat ceiling beneath horizontal framing akin to rafter ties. This leaves a small triangular attic space above (enough room to crawl around, but not enough room to stand).

In Energy efficiency and durability | Asked By rob williams | Nov 5 14
11 Answers

Hydronic radiant: how do I evaluate H-E tank vs tankless systems?

Hello GBA forum,

In Mechanicals | Asked By Brian Gray | Nov 3 14
6 Answers

Exposed fastener metal roof vs. standing seam?

I'm reading Martin's awesome roofing primer: http://www.greenbuildingadvisor.com/blogs/dept/musings/martin-s-ten-rule...

And I came across something a little confusing to me: the preference of an exposed-fastener metal roofing over standing seam. I think I understand that an exposed fastener job is easier to install and therefore cheaper. But is that it?

In Energy efficiency and durability | Asked By Nathaniel G | Nov 4 14
4 Answers

Duct work

Hey guys
In a recent post (spray foam insulated homes) there was a picture of a hrv and distribution box showing the white round plastic duct work leaving the box. Why can't we use this type of duct work for our regular hvac duct work? I Would think this material would deliver air more efficiently than rectangular metal ducts. Installation would be easier as well.

Thanks for your help

In Mechanicals | Asked By russell berenson | Nov 4 14
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