Hey Charles
I’ve attached a couple of pdfs of the house floor plan. A few notes:
- The house faces approx south to north, the family kitchen area is in the southern end.
- We’re reducing the number of small windows in the northern for cost, ease of install, and thermal bridging.
- We aren’t building the chimney per plan but will have a stand alone fire stove
- [Until now, we were planning] to use TimberHP as insulation for walls (R40+) and ceiling.
- Using trusses with raised heel to get R60 – unvented attic space.
- HVAC will be via 3 mini splits. The fireplace will act as backup (we’re in 05905, so we get the cold here)
- Concrete slab foundation in place with r20 under the concrete and isolated from the frost walls.
- The plan for water, electricity and ducting is to use some the 10’ ceiling height and build a chase.
Reasons I reached out:
- I saw the Linkedin post for the Maine build and realized eco-panels should be good for our winters.
- Our timing for building has been stalled by selling our current house and we’re now looking at starting in November – not optimal. So speed is key.
Cheers
Jim
Good morning Jim,
Thanks for the additional information. Just to confirm – you want us to consider 10’ wall height for the long sides of the house? And I see a 4:12 roof pitch. Wall height is not labeled specifically in the drawing.
We can certainly provide you an estimate for our roof panels – they are R53 at standard temps and they work at R60 when you get down in the 15 degree range – this is explained in the presentation materials I sent you last night.
For the fireplace – will that be a traditional fireplace or a “direct vent” fireplace (which I would HIGHLY recommend)?
Regards,
Charles Leahy
Eco-Panels
One other item – we’d go with the Zip sheathing in any case, since its durability gives me a little time to put on the siding.
Cheers
Jim
Thank you Jim. Glad you are looking at a direct vent fireplace – the traditional ones can cause problems in a very tight home. I also hope you are looking at an ERV – or HRV for your climate that will be timed/synced with your vent fans.
Will this be a direct-attachment of the metal to the roof panels or will you create a “cold roof” and lay out furring strips to create an air-gap?
Michael,
Please spec out a 5/8” thick top skin for the roof panels (does not have to be Huber).
Regards,
Charles
Yes to HRV
Metal roof – originally budgeted for standing seam roof on ice shield type product over 5/8″ Zip. If we think about a vented attic space, then furring strips would be the way to go. The additional consideration is using the eastern side of the roof for future solar panels.
Cheers
Jim
Thanks Jim, it seems like you have this well planned out. Regarding roofing underlayment, I would not recommend a non-permeable underlayment but rather a vapor permeable underlayment. There is a great peel-n-stick vapor-permeable underlayment with the Vaproshield Slopeshield product – and there are a growing number of other brands out there. If you are not already aware, the reason this is done (it’s a building science thing) is the closed cell foam of our panels will never allow the drying of the top skin of sheathing (if it gets wet) to the inside, so it always must dry to the out. But if it is covered with a traditional ice-and-water-shield which is basically something like an impermeable rubber membrane – it can not dry through that membrane. So the wood might stay wet and rot over time (and a metal roofing skin will certainly not let it dry – that’s why some people still create an airgap – as a safeguard to allow drying to occur). With a vapor-permeable membrane, at least if water penetrates into the top skin of the panel it can dry itself out through a vapor permeable membrane).
Regards,
Charles
Thanks for this – quite the rabbit hole to go down.
How do you handle vapor inside the wall assembly ( if it’s in the literature you sent apologies I didn’t catch it)
Cheers
Jim
Good afternoon Jim,
Great question! The great thing about a product like ours is that our closed cell foam is vapor impermeable. So as Joe Lstiburek at Building Science Corp. says – it “dries to the out” – meaning, from whatever direction moisture enters, it will dry out to that same direction. It can not pass through due to the very low permeance of the closed cell foam core. Otherwise there IS NO VAPOR INSIDE THE WALL CAVITY because with the injected foam occupying every bit of vacant space there is no place for that vapor to reside.
Of course, the attic space needs to be conditioned along with the rest of the living area to keep moisture from collecting and causing problems. And interior panel seams need to be taped.
Regards,
Charles Leahy
Eco-Panels
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