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9 Answers

Unvented roof underlayment and rafter bay insulation

Hi guys...first time poster, love the site its been a huge help. I've just finished framing my home in Montana and am ready to move on to the roof. It consists of multiple single pitch decks ranging from 1.5" - 2" in 12. Framing is 2x12 rafters.

Asked By Adeeb Hattar | May 27 15
1 Answer

Overinsulating or underinsulating?

We have a home built in 1986 in Columbus, Ohio (Zone 5). We are replacing our siding due to hail damage and plan to have the following layers on our home:

Existing:
1. drywall
2. 2x4 walls with unfaced batt fiberglass insulation (R?)
3. polyiso 1/2"? - (old, some gaps, foil faced, says "R3.6" on the face)

New:
4. 3/8" EPS w double foil face (~R1.5) - http://www.thermalbuildingconcepts.com/technical/propertySheet/ps-Physic...
5. Tyvek
6. Cedarmax insulated vinyl siding (R2.4) - http://www.proviaproducts.com/productdetail/vinyl-siding/cedarmax/

Asked By Chad B | May 27 15
1 Answer

Minisplit in tandem with a conventional heat pump?

A friend is getting ready to build a 2800 sq-ft retirement home in the hot and humid south, (Houston). His HVAC contractor is recommending a 5 ton, two stage heat pump. This is ~ the traditional 1 ton / 500 ft2 formula that prevails in this area with the added benefit of the two stage compressor. But 5 tons seems like a lot for a tight house and 2.5 tons is hardly the optimal dehumidifier in the light HVAC seasons. The house will be insulated with closed cell foam in the walls and under the roof deck. It is not what you would call an open floor plan.

Asked By Dean Wiley | May 27 15
5 Answers

Attached garage with steps leading into basement

We are building in SE Wisconsin. Currently just figuring out floor plan, in a rough design stage. Main level of house approx 1 ft above grade to approx 4 ft above grade on south side. Basement of house to be partially finished on south 1/2 of house. Attached garage on north side of house. Garage to be on same level as main floor of house. My questions deal with having a stairway in the garage leading to the basement level.

Asked By Dirk Denzin | May 26 15
2 Answers

Skylights that sit flush but don't leak! Do these exist?

I am trying to daylight a currently unused attic under a shingle roof. Because we're in a historic district, we're not allowed to visibly alter the roof's silhouette (so no dormers or protruding skylights). My architect has proposed switching to a standing seam metal roof with thin glass skylights slotting into the metal seams (as seen in the attached pic). I'm worried that the lack of flashing will lead to leaks. Does anyone have experience with skylights that sit flush but don't leak? Or am I chasing a unicorn?

Your feedback much appreciated!
Nathalie

Asked By Nathalie Jordi | May 27 15
5 Answers

Perlite in wall cavity recommendations.

I have a 2x4 wall cavity that is only about 5" wide. The cavity contains a steam pipe which is uninsulated. The cavity is obscured by another wall that makes access to it very difficult.

I would like to fill the cavity with perlite to insulate the steam pipe. I can close up the wall to prevent the perlite from leaking out, and have access to the top.

The house was built in 1928. From the outside: brick, air gap, roofing felt, 3/4" tongue and groove.

Asked By Kurt Kiley | May 25 15
1 Answer

Is cellulose fiber insulation treated for mold/water infiltration?

how durable is cellulose fiber insulation on a typical say 3 bedroom family house, will it typically last 20 years under normal usage conditions.

Asked By Alice Onaga | May 27 15
3 Answers

Add exterior foam -- but (woops) poly sheeting?

This is a follow up to my question from yesterday - "Add exterior foam -- but paper-faced batts?"

Well, at the advice of my builder I cut some test holes and darn.. poly sheeting over the batts, not kraft paper as I thought.

So the same question applies - what are my options, if any, for adding exterior insulation during this window replacement project?

Thanks again.

Kyle

Asked By Kyle Hollasch | May 27 15
2 Answers

No footing, no drainage?

Yesterday I was excavating a corner of my house to add Roxul to the exterior of my slab on grade foundation walls to help with my hydronic heat problems.

To my amazement, I found a section the foundation wall that has no footing. It is where the garage footing meets the house foundation wall. There is a corner and the house side of the foundation wall is missing a footing for about 2 feet. After this you can see the wood they used to form it go back below grade where I'm assuming a footing starts for the rest of the wall.

Asked By Michael McArdle | May 27 15
10 Answers

Building wrap as an air barrier above a cathedral ceiling?

Hello,
I'm building a small house in Alaska with a 12/12 cathedral ceiling. I'm planning on a 1 1/2" vent channel above the fiberglass batts I will be using. Venting will be the usual eave to ridge vent design.
I've been advised to create an air barrier above the batts so they aren't wind washed by air traveling up the vent channel.
I haven't been able to find much information on this approach, and none of the builders in my area are familiar with it. Can anyone supply me with some "do's and don't's" one this technique?

Asked By Justin Smith | Apr 2 15
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