Hi everyone, im planning on building a new SMALL home in Maine. Ive had several homes and now we are getting older and want a small, energy efficient home around 900sq ft. Its going to be ranch, open floor plan and hope to heat the entire place with a pellet stove. Here is where it gets interesting..... Just about every home in my town has a full basement. We do not want a basement, its dusty, smelly, moisture and we DO NOT WANT ONE or need one for storage. I ran across this link and was curious your thoughts. http://www.jlconline.com/Images/Super-Insulated%20Slab%20Foundations_tcm96-1069481.pdf We are considering exactly this setup. Everyone in here knows alot more than we do so i could really use some good solid opinions on this option. Please dont give me the benefits of a basement, but give me the bad side of the link above instead structurally. We cant afford a basement and we do NOT want one for any other reason - Storage, ease of putting in plumbing and electrical. We will work around those issues. Thanks so much!

GO Logic in Belfast as well a number of other Maine builders build homes regularly on insulated slabs. No reason not to. Maine Green Building in Portland sell a footing form which you can use to build a type of Alaskan floating slab, or you can use frost walls. the only caution is to make sure the footings or slab has excellent footing drains, insulate it well, and thermally isolate the slab from the surrounding ground.

Are you aware of anywhere in Maine to get that 6" foam in large lengths to go under the ICF exterior beam as in that link i listed?

Ask at MGB. Also, Branch River plastics in RI manufactures EPS & they can make & ship it. Their might be an EPS manufacturer in ME also, try googling. You might ask about borate treated EPS to help keep the bugs out.

MGB?

mainegreenbuilding.com

Bob did you have a chance to check out the link in my original post? Curious your thoughts on this exact procedure - not the monolithic but more the ICF beam.

I could use readily available 2" stuff and use two layers and dont criss cross and tape the seams i suppose ?

steelejones1-

I could not get your original link to work. I can find http://www.jlconline.com/formwork/super-insulated-slab-foundations.aspx, which may be similar?

yeah and 'open slideshow' thanks

or actually on that linke you posted above, you can click on DOWNLOAD PDF, thats what i did....

My budget is very tight and im nervous putting a small house on a slab. So im fighting money and my nervousness on insulated slab in this fashion.

I hadn't been able to load it from your link, but have now. Note that the author is one of the principals of GO Logic. I understand your concern; I've had my own, but a lot of builders are using the method and it seems to work. You can, though, go the "standard route" with a 4' frost wall, backfill & compact the interior and pour a slab on that. Again, you must thermally isolate the slab and insulate the walls and under the floor.

Posted By Bob I on 10 Sep 2013 02:28 PM
I hadn't been able to load it from your link, but have now. Note that the author is one of the principals of GO Logic. I understand your concern; I've had my own, but a lot of builders are using the method and it seems to work. You can, though, go the "standard route" with a 4' frost wall, backfill & compact the interior and pour a slab on that. Again, you must thermally isolate the slab and insulate the walls and under the floor.

Try this link, click on the slideshow.

The science behind frost protected foundations is sound- it's not crazy at all.

I have a frost protected insulated slab, and it is wonderful. I am in the Finger Lakes of NY, only needed a 12 inch slab thickness at the perimeter, the rest is 6 inch. My house is 2 story 1399 sq ft per story and it works great, don't see why it shouldn't work equally well for your smaller house. This is a very affordable foundation for a house, and has been used around the world with great success for many decades. An FPSF is very green, and one of the first green things it saves is money.

-Rosalinda

Guys, I can only access 4x8 sheets of EPS or XPS for the under the ground, under the slab insulation. What do people do to keep them together or seperating or sealing them from seperating to let the cold up ?

Posted By steelejones1 on 19 Sep 2013 08:36 AM
Guys, I can only access 4x8 sheets of EPS or XPS for the under the ground, under the slab insulation. What do people do to keep them together or seperating or sealing them from seperating to let the cold up ?

Compacting & leveling the gravel, then taping the seams with the appropriate tape works and is fairly standard practice.

For R10 or higher going with two layers with overlapping seams is even better, with both layers taped, but that's more tape, and more labor.

When you have a choice, EPS is a greener option with a more stable long term R-value.  XPS is blown with substantial amounts of HFC134a, which gives it a higher initial R/inch, most of which is lost in the first 50 years as it escapes to warm the planet- it's an extreme greenhouse gas (~1300-1400 x CO2.)  EPS is blown with pentane (~7x CO2), most of which has dissipated by the time it hit's the distributor's warehouse, and thus R-effects of the initially encapsuated pentane are not included in it's R-value rating. (The closed cells are already filled with air by the time the samples get tested.)

Is this a special type of tape you recommend?

Posted By steelejones1 on 19 Sep 2013 11:53 AM
Is this a special type of tape you recommend?

Siga Fentrim 20 is probably the best, but hard to find in the US outside of a few west coast specialty supply outlets. Almost any housewrap tape will cling long enough to get the concrete poured, after which it's locked in place.  Adhesion of housewrap tapes to XPS is a bit firmer than to EPS, but not enough to matter. I've seen it done Tyvek Tape.

Dana, Is slab EPS foam worth it for a Zone 4 climate?