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7 Answers

Why insulate stemwalls?

For slab-on-grade construction there are 3 insulation locations - edge, sub-slab, and stemwall (down to the footings). In FHB 245, Martin says it is important to insulate stemwalls to a minimum R10. Code says a minimum of 4ft of R10 in any combination of vertical, sub-slab, or exterior skirt. Building Science shows an edge and sub-slab (no stemwall) insulation diagram here. So why stemwall insulation? Is it to prevent heaving below the slab?

Asked By Matthew Michaud | Dec 21 16
8 Answers

ZIP Window Detail with Exterior Insulation

On ZIP's website, they have window details which appear to combine the flashing/window buck of an outie window, but it is shown flashing into a WRB (in this case the ZIP sheathing) located behind the exterior insulation.

Asked By Derrick Krienert | Jan 15 17
9 Answers

Exterior wall polyiso worth it?

I live in central Texas and I'm debating whether adding 3/4" Polyiso to the outside of my exterior walls. would be worth the cost. I originally planned on it, but since my wife and I are doing the majority of the work, it has come down to just not having the time (we both work full time jobs, plus a bit more), and the initial cost of it.

Asked By Jacob Cox | Jan 17 17
13 Answers

Exterior Rigid Foam Under Sheathing?

In my local area there is a green building consultant that recommends a CI panel which is basically EPS foam glued to OSB. The way this is installed would be the OSB to the exterior. Almost every house I see with exterior rigid foam in my online wonderings is covered with blue and pink XPS, the OSB sheathing is nailed directly to the studs and is completely covered with the rigid foam. This leads me to the following questions:

- Is anyone familiar with these kind of CI panels?

Asked By Joshua Greisen | Dec 8 16
9 Answers

Another "help me design a wall" thread

I've read wall build articles here but I'm still ambiguous as to the placement of barriers. I've also watched Dana's series titled, "Extreme 10 foot or less snowy knoll patch skiing", but couldn't find any relevant information there.

Zone 5. Inside to out: (sealed?) Drywall | 2X6 studs sealed with Ecoseal and filled with dense pack | either OSB or ZIP taped | 3" poly foam taped | rain screen, vinyl siding.

From what I've learned here this wall will need to dry to the interior.

a few questions, if I may?

Asked By Drew Baden | Dec 28 16
1 Answer

I need recommendations for the best way to insulate and air seal the walls and floors in in house built in 1977 in the Seattle area.

Existing walls - 2x4 @ 16" o.c.
Sheathing - 1x8 boards
Siding - 1x8 lap siding to be removed
Existing subfloor - 2x6 T&G
Floor structure - 4x10 beams 4' o.oc.
Min req'd R-value for the walls is R-21
Min req'd R-value for floors is R-30

Asked By Stewart Breslin | Jan 16 17
0 Answers

Can Roxul Comfortboard 80 be installed on roof deck in non-vented assembly 70psf load requirement?

Passive house build in Northern California

Asked By Forrest Kerr | Jan 14 17
14 Answers

Air sealing the building envelope while avoiding moisture issues

First off, thank you GBA community for all the support so far in getting my project planning done for my net zero build. I've been doing a good amount of research on the best way to provide a good air barrier for my future home. I have significant concerns on a cost effective way to get the proper air sealing in order to hit the goal of sub 1.5 ACH. Below is a quick overview of what the build envelope looks like so far:

Asked By Joshua Greisen | Jan 5 17
23 Answers

New siding for an old house, and a couple other questions

I asked a couple questions a while back regarding installing rigid over existing clapboards with a WRB and an inch or so of rigid insulation - I couldn't seem to respond to those answers but I have a couple more to ask If I use semi-permeable polyiso board over the existing wood siding so it can dry to in both directions, can a fluid applied WRB be applied to the outside of the rigid board. Alternately, If I put either housewrap or fluid applied under the rigid, should the joints be taped? Reading on Dupont's website they recommend not taping the joints.

Asked By Michael Mohr | Dec 14 16
5 Answers

Free-standing porch deck and roof with mineral wool exterior insulation

I'm looking at building a one-story porch with a deck and shed roof connected to a new two-story house with 4" of mineral wool exterior insulation, 1x4 battens screwed into 2x6 studs 24" OC , and siding.

I agree with the preference often expressed on this site of not attaching the deck to the house structure, both in terms of water issues and thermal bridging.

My current thinking:

Asked By Pat Kiernan | Jan 11 17
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