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Post by fairbanks1981 on Mar 28, 2010 19:28:45 GMT -8
I am looking at heating about a 700 square foot cabin (not built yet) and I may need to build on a post and pier foundation system do to likely permafrost in the area. Does anyone know of any resources to help design the foundation for the heavy load of a rmh with heated bench(1500-2500lbs)? I have checked out a lot of the masonry heater websites but unless you are building on a concrete pad they only recommend consulting with an engineer, I was hoping there may be more information online?
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Post by canyon on Mar 29, 2010 0:04:31 GMT -8
One of the beautiful things about a heated bench is that you can spread the weight out over a larger area than a traditional masonry heater. This makes it easier to support with traditonal framing materials by just lowering the spans and adding more joists. You might need a few extra piers. It really is site and design specific. I don't know about any online sources, but check the library for a good old book called "From the Ground UP" by Cole and Wing which has some good words on the subject as well as span tables. Once you understand the forces at play, it really is elementary math. Don't be afraid to seek advice from a builder or two once you've done your homework. Or go visit the upcoming structural engineers at UAF and bribe 'em with beer at the pub! But do your homework first!  |
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Post by fairbanks1981 on Mar 29, 2010 17:01:00 GMT -8
Thanks Canyon, that makes sense if you "spread the weight out", especially if you make it smaller than the average Masonry Heater which looks like they start off around 3-5 tons! I will check that book out and probably plan on spacing the joists at 16" with extra support at the center ( I think I may opt for a 30' yurt instead of the cabin while we wait to build our "real house")
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Post by raitsaar on May 8, 2010 20:20:15 GMT -8
Hi fairbanks1981, not sure if it helps you or not but i still wanted to clear out some common misunderstanding about masonry heaters. Fyi the average output (how much heat will i get) of masonry heater per ton is 1ton = 1kw. Usually the masonry heaters weight no more than 1-3 tons
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Post by woodman on May 9, 2010 17:40:48 GMT -8
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Post by rocket_richard on May 9, 2010 19:23:38 GMT -8
The FPSF (frost protected shallow foundation) would not be appropriate for permafrost conditions. The FPSF would be opposite to what is needed in permafrost, mainly keeping the ground frozen. The FPSF's built in alaska that I read of in the above link are not built on permafrost but on ground which freezes to 13 ft. in depth.
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Post by Donkey on May 10, 2010 10:58:36 GMT -8
Ya..
In permafrost areas, you want the ground underneath to STAY frozen.
The FPSF tech is for MUCH warmer areas.
All that said, me thinks too much emphasis is placed on expensive, high tech, ultra gizmo solutions.
Frost heave is caused when moisture, trapped between (relatively) unyielding surfaces freezes, expands and shoves out of the way the most yielding of the two. Usually the most yielding will be the foundation of your home.
Seems to me the least difficult (and least costly) method(s) would be to keep the water out (difficult), give it a fast way out when it gets in (easier), and/or provide space for the water to expand (non-destructively) when it freezes (not too hard).
It occurs to me that the building industry has a vested interest in promoting difficult and expensive fixes for what shouldn't really be that hard after all.
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Post by woodman on May 11, 2010 4:00:24 GMT -8
Donkey :It occurs to me that the building industry has a vested interest in promoting difficult and expensive fixes for what shouldn't really be that hard after all.
Boy you got that right ya think they have any influence with the building codes in the city's across America. ;D
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Post by Donkey on May 12, 2010 12:53:48 GMT -8
Donkey :It occurs to me that the building industry has a vested interest in promoting difficult and expensive fixes for what shouldn't really be that hard after all. Boy you got that right ya think they have any influence with the building codes in the city's across America. ;D Ya think??  |
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