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11 Answers

Not enough XPS over roof - should I vent?

I am in the Washington DC area - Zone 4. I just had a 1.5/12 single slope roof framed with 2x8's for a 14x20 new block wall garage. On top of the rafters there is a layer of plywood followed by 2" XPS rigid foam followed by another layer of plywood and then an ice and water shield across the entire roof. This week there will be a standing seam metal roof installed on top.

Asked By Calvin Bouchard | Feb 12 17
1 Answer

Vented crawlspace - air barrier

I am trying to figure out the construction details for a new home build in Washington state, climate zone 4C (marine). I have been spending many hours trying to educate myself on GBA and with the "Musing of an Energy Nerd" (great book Martin).

Given the unique climate in the Pacific North West, the prevailing design for homes is vented crawlspaces. They appear to work well due to the lack of hot humid air conditions. I also understand that an unvented crawlspace is also an option but brings with it an additional level of concern for venting and radon control.

Asked By user-6824154 | Apr 28 17
4 Answers

Final unvented cathedral ceiling insulation questions

I posted in my previous thread about my roofline being problematic (which was pointed out quite often!);
PLEASE KEEP IN MIND THIS HOUSE IS ALREADY FRAMED! I cannot change the roofline unfortunately (had I known then what I know now)........with that in mind please see my questions below:

I have come to the conclusion that I need to do Closed Cell Spray Foam in the main areas where the roof is not a simple plane but interrupted with valleys, etc. (?)

Asked By User-6816910 | Apr 27 17
5 Answers

Compact re-roof with polyiso over spray foam?

Hello everyone!

I'm in the Lehigh Valley, Climate zone 5A (borderline 4A), and I have a roof that needs to be redone and insulated far more than it is now, it was originally a cold cellar back in the day, and is a relatively small area- 17' x 17'.

Asked By GreenStoneHome | Apr 27 17
2 Answers

Vented and unvented attic space

We are currently considering foam insulation during the framing phase.

Basically the trusses span over our patio area, approximately 15' with glulam at bird's mouth.

When looking at foam they will create a 'rake wall' with foam to enclose the attic from top plate to roof decking.

Do we need some sort of venting in this section of the attic (outdoor patio)? It will be an unconditioned space.

Asked By Espy1 | Apr 27 17
5 Answers

Manufactured foundation drains, e.g. Z-Drain

Our builder wants to install the foundation drain on top of the footer instead of alongside of it. We complained that this would potentially give us a line of standing water above the footer/foundation wall joint (though it would remain some inches below the basement slab level. ) We will have Tremco Tuff n Dri waterproofing all along the wall and along that joint, so if it does a perfect job indefinitely then we should be fine. But if not, we could get some wicking up that wall.

Asked By William Costello | Apr 26 17
4 Answers

Housewrap under rigid foam AND taped rigid foam at windows

the set up: Climate Zone 3. I'm using a standard house wrap between the OSB sheathing and the 1" rigid foam. The rigid foam will have all seams taped and will act as the primary WRB behind 3/4" vertical furring and lap siding. The Question : How do I terminate the house wrap at windows? just bring all the way into the "outtie" window bucks (caulk to buck), install rigid foam, then install window peel and stick flashing on bottom/part way up the sides. Install window. Would you recommend a 2nd layer of house wrap around the windows? Attached to the rigid foam?

Asked By Inger Peters | Apr 17 17
3 Answers

XPS foam on exterior side of window and door headers

I think have seen a similar question before but wanted to refresh.

Assume building a 2x6 wall. Using Mineral Wool for insulation (which means a smart membrane on the interior side of the wall). When framing headers for doors and windows almost ALL of them only need double 2x8, typically with ply sandwiched to make them flush with the stud depth. In 2x6, simply 3 pieces of header lumber are nailed together to get the 5.5" thickness of the stud.

Asked By Nicholas C | Apr 23 17
18 Answers

Insulating new construction home with no exterior rigid foam

Okay smarties, here is my scenario:
-I am Building a new home that is currently in the framing stage. 2x6 studs with Forcefield Sheathing (essentially same as ZIP).
-I am in in Climate 5 (iowa)
-My home is a California style architecture, 1.5 story, pitched roofs (now I realize why this is better suited for CA-vented roofs better option in Midwest!)
-My initial goal and how I came across these articles was to prevent mold (still is)

Asked By user-6809983 | Apr 9 17
3 Answers

Modifying Existing ICF Walls

We are considering purchasing a house built completely with ICF walls. Our purchase is predicated on being able to expand windows in two areas and lengthening a current window area to install french doors to a deck. The expansion of the windows would involve removing the wall between two windows and installing a wider three panel window.

Is this possible with ICF construction. If so what are the key things that must be considered in making these modifications.


Asked By ledICF | Apr 22 17
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