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4 Answers

Attic air barrier

So I have my plans for my new build complete, but looking for the best detail on how to air seal the ceiling between the main floor and unconditioned attic space.
The house is one story with walk-out basement, the attic will have at minimum R60 blown-in cellulose, the raised heel trust will allow for this or more.

Asked By Dave B | Mar 6 18
1 Answer

Rockwool on roof sheathing

For a roof with exterior insulation on top of the sheathing, is it possible to use rockwool instead of rigid foam?

I was reading here about how mineral wool, as an an air permeable insulation, was not a good choice for inside of stem walls, as air can still contact the cold stem wall surface and condense. Would the same apply to roofs, avoid air permeable insulation on top of the deck, because condensation will still happen?

This is for a compact roof assembly in CZ3-coastal, zip 95060. Roof detail is attached.

Asked By Phil Boutelle | Mar 6 18
4 Answers

Sub-floor options for addition

I'm in the design process of an addition to my house, 24x36 with a great room and master bedroom/bath. A garage will be under this addition, I know, I know, not the greatest idea but I need more garage/storage space for my and the kiddos toys!

As for the sub-floor, can I install rigid foam .5-1" on top of the joists as an air barrier with some r-value and OSB on top of the rigid foam? I was thinking of going this route and using Roxul in-between the joists then drywall on the garage ceiling.

Asked By Rob_K77 | Mar 1 18
16 Answers

Wall questions

My new home was designed with 2x4 staggered stud walls on 2x8 top and bottom plates with 2.5" closed celland 4.75"open cell foam.The engineer has specified areas in the main portion of the house (that has 17' tall ceilings) to be balloon framed with 2x8's and sheathed in plywood on both the interior and exterior. These are only 4' wide sections at 4 corners, but would this combo cause any problems?

Also, the engineer was not familiar with staggered stud walls. Is there any study that looks at the strength of this kind of wall vs. a standard 2x8 wall?

Asked By Kevin Spellman | Feb 28 18
2 Answers

Contractors, expertise, and details for exterior rigid foam on roof

Zone 5a, Southest Michigan. Based on the article Combining Exterior Rigid Foam With Fluffy Insulation, I'd like to have two 2" layers of polyiso installed on the exterior of the roof sheathing when we re-roof our 1958 tri-level (along with fluffy insulation inside). We'll likely do some additional envelope and mechanical improvements, but first priority is the roof.

Asked By Phil Ray | Feb 28 18
8 Answers

Climate Zone 3C: Crawl space, roof, and wall systems review

I'm in the design phase of a remodel of an existing 2 story house, CZ3 coastal, zip code 95062. The scope includes a new foundation and gutting the house with some interior walls moving, but for the most part keeping the existing exterior shape and roof line. Goal is a high performing house (well insulated, air sealed, mechanically ventilated, high IAQ and minimal heating and cooling loads). I've attached a line drawing of the shell for reference.

Asked By Phil Boutelle | Jan 9 18
1 Answer

Sealing framing to subfloor

What is the best way to seal bottom plates to subfloors when framing? In my current house, I went around and caulked after the walls were up. Is it better to put a sealant on the bottom plate before raising the wall? How about a 1/4" Sill Seal like Denarco makes? Or an EPDM gasket? My walls are 2x8. I don't want to spend huge amounts of money, so what is most effective, and cost effective?

Asked By Kevin Spellman | Feb 23 18
6 Answers

Is PERSIST really practical in coastal Maine?

Hello, all! We are in the planning stages for building a ~1300sft home in coastal Maine (6A, I believe), and are trying to strike a balance between performance, low-maintenance and cost. We've found Persist to be an elegant solution, and we really like the look of having the exposed framing on the interior - Matt Risinger's work in Austin comes to mind.

For us to reach the desired R values of the walls, there seems to be good details and best practices out there for fastening thick amounts of foam.

Asked By Geir Gaseidnes | Feb 21 18
12 Answers

Lessons learned from exterior basement insulation retrofit

I've attached a link to photos and comments that I created to share my recent (last week) experience with an impromptu opportunity to add exterior insulation to a portion of my basement. Lots of things I could have done better here, but in the end I'm glad I spoke up and asked to make the house better.

Asked By Mike McLaine | Feb 3 18
11 Answers

Casement windows?

I'm looking for highly efficient triple glazed windows with a high solar heat gain coefficient for use on the south side of a new construction home in Massachusetts (Climate Zone 5). I like Schuco windows, however, I am looking to compare with a window that performs similarly but doesn't open into the living space. Any suggestions?

Asked By Leslie Whelan | Feb 26 17
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