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Hi,
I live in northern Michigan (read COLD). I’m putting up a ‘garage’ which will be my heated shop. I’m planning a floating, monolithic slab, with one course of blocks to get the sills above grade. Here’s my question: How do I insulate the foundation.
The material I’ve read says to install a sheet of extruded polystyrene insulation around the outside of the foundation. It doesn’t say how to protect it so the sun doesn’t eat it up. I plan to sheet the walls with 7/16 OSB, then use vinyl siding over housewrap. If I use 1″ polystyrene, it will stick out farther than the vinyl siding. Can I get away with just a flashing over the foam and not worry that it sticks out farther than my siding. Seems like it may look a little wierd.
Also, any thoughts on additional insulation for the foundation?
Finally, any thoughts on the wisdom of gas vs wood heat. I plan to keep the thing at around 40 degrees when not in use, and warm it up to around 60 when I’m in there. I expect to keep a small gas heater, but am wondering if a wood stove will save appreciable $$. The shop is 30 x 40 x 10.
Thanks for the help.
Frank
Replies
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Frank
The Styro around the perimeter should be protected regardless from both UV and mechanical damage. It can be most easily covered with cement board to below grade. Fabricate a flashing (like a backwards flattened Z) that will go up under your siding, across the top of the styro and down over the cement board. The only way to beat the obvious step would be to pack your walls out.
You might consider 2x4 framing with exterior XPS (for R20 walls) and then carry the XPS down to below grade, that way the starter course for the vinyl (typing that wword makes my ffffingers ssshake) will act as the flashing over the top of the cement board.
Are you considering styro underneath the slab around the interior perimeter?? Alternatively bury sheets of XPS horizontally around the perimeter on a slight downward angle about 1' below grade. Helps with frost heave!
As far as heat is concerned a wood stove needs to be baby sat... a furnace of some type can be thermostatically controlled and looks after itself . Put the money into insulation details and you will saveon fuel $$.
-pm
*Frank,As far as a natural gas heat vs. wood, from the insurance point, you will spend twice as much trying to insure your new structure if you apt to use wood as a heat source.I myself am from the u.p. of mi. and I had the same question for my garage.keith
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Hi,
I live in northern Michigan (read COLD). I'm putting up a 'garage' which will be my heated shop. I'm planning a floating, monolithic slab, with one course of blocks to get the sills above grade. Here's my question: How do I insulate the foundation.
The material I've read says to install a sheet of extruded polystyrene insulation around the outside of the foundation. It doesn't say how to protect it so the sun doesn't eat it up. I plan to sheet the walls with 7/16 OSB, then use vinyl siding over housewrap. If I use 1" polystyrene, it will stick out farther than the vinyl siding. Can I get away with just a flashing over the foam and not worry that it sticks out farther than my siding. Seems like it may look a little wierd.
Also, any thoughts on additional insulation for the foundation?
Finally, any thoughts on the wisdom of gas vs wood heat. I plan to keep the thing at around 40 degrees when not in use, and warm it up to around 60 when I'm in there. I expect to keep a small gas heater, but am wondering if a wood stove will save appreciable $$. The shop is 30 x 40 x 10.
Thanks for the help.
Frank