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tacmedic
Member
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# Posted: 22 Nov 2012 11:05
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Hello everyone. I have been following the site for years and my wife and I, along with our 4 kids are 6 months away from building our full time cabin. We are planning on building a 24x24 gable cabin with loft. Attached to that will be a 10x24 shed addition on each side, and a 10x12 gable addition off the back. We are looking to build the simplest, functional, off grid cabin possible. We are building in Maine, with okay access for my pickup with a trailer, but not so easy access for heavier equipment. I have been researching foundation options for what seems like an eternity and cannot make up my mind.
The latest and simplest idea I had is to lay a 6 inch bed of gravel, tamped down and leveled. Then using multiple skids. 3 - 2"x12"s PT sandwiched together. I realize this is a cheap option, but would it work. I would run skirting around the cabin so that weather cannot get to the skids. Also considered wrapping the skids with a vapor barrier. The other option is to dig the 48" to the frost line, back fill to grade with tamped gravel, stack cat blocks, then build on top of that. I understand that I may have to jack and relevel occasionally. Keep in mind that I do not have to worry about plumbing. We are going to use a composting toilet and gravity drained gray water.
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cobra grover
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# Posted: 22 Nov 2012 19:18
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So you plan on having your cabin "float" on the foundation? I don't see any advantage to digging down 48" and then backfilling with gravel. I think the reason you dig down below the frost line is to put a base down to build on with sold material like blocks, concrete, or wood posts. If it's going to be full time I think I would do a full concrete footer and blocks. You didn't say where you are located but if you are in a warm part of the country your plan may work just fine. You might think about doing concrete sonotube piers.
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tacmedic
Member
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# Posted: 23 Nov 2012 05:43
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Yeah, the plan was to dig down 48" putting me 6" below the frost line. Back filling with gravel to grade supposedly works well because gravel doesn't heave much with frost. Or so I read. The other thing is that I can jack one point at a time and replace cat blocks if they crack or back fill with more gravel as needed. The cabin will be located in central Maine so frost heave will be an issue. My thoughts were that the simpler I keep my foundation, the easier it is to correct issues in the future if need be. I was planning on using the same type of foundation as coyotecottage.com because of its simplicity. The overall cost of having to make a driveway that would support heavy machinery plus the cost of delivery to do a traditional foundation at my cabins location would be astronomical. Thanks for replying, I can use all the help I can get.
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MtnDon
Member
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# Posted: 24 Nov 2012 14:43
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For the size of what you are planning, it is my personal opinion that it is foolish to mess around with anything other than a proper foundation that will not result in having to "tinker" with the leveling. If it was a small occasional use cabin and not a full time residence, I might think differently. But you will have nearly 1200 sq feet in total. That's a house and deserves to be built as such, IMO.
A trench filled with gravel is only good if there is a well designed outlet for the water that will collect in that space.
If you can't get heavy concrete trucks up there then there are alternative solutions that will work. Do a web search for permanent wood foundation, or PWF. There are design / build guides available online. When followed to a "T" they work.
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hakalugi
Member
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# Posted: 27 Nov 2012 13:26
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mtndon - thanks for the tip on PWF. The design guide is on my way as my site makes heavy equipment a challenge as well.
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beachman
Member
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# Posted: 27 Nov 2012 14:21
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I agree with MtnDon about the "best" way of building the foundation. Failing that, there is a great product out call PostTech. These are posts that are screwed into the ground at intervals depnding on the weights you need. They can be screwed in with unit attached to an ATV for access. They are also levelling so you can make adjustments here and there in the years to come - but the word out there is you will not need to make that many. Might be an alternative - however, this will leave an exposed crawlspace that you may or may not want.
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MJW
Member
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# Posted: 27 Nov 2012 14:41
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Looks like these PostTech guys are only operating in Canada right now. 
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GomerPile
Member
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# Posted: 27 Nov 2012 15:18
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Given your site limitations I would use the post and pier method. Cardboard tubes, bags of cement, and rebar can be transported to your site by the sounds of it. Save your back a little by renting an auger if your soil conditions will allow its use.
If you are worried about the exposed crawl space there are a number of ways to close it in.
Couple notes on frost
Frost heaves are caused by water in poorly drained soil that is below freezing. Remove any of these things and you eliminate heaving. Dig 48 inches and you have soil that is above freezing. Insulate the ground with the correct R value material and you have soil above freezing. If the insulation is sloped away from the house for some distance (24 inches) you reduce the amount of water that can freeze.
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Kirk
Member
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# Posted: 8 Dec 2012 22:38
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Good advice from others... here is what I did for a 20 X 24 modified post and beam (in the members project section)... I used 15 yds of gravel fill, poured a slab, ran conduit for both water and electrical wiring ...including plumbing (for possible future use - I am using a compost toilet at present - very pleased). I wanted the slab set up for both water / sewer in the event I sell and others' want to add such.
I also have an 8' overhang on all 4 sides ... that drains water with guttering well away from my slab (and provides great protection for my logs). What I like about the slab... much cooler in the summer and warmer in the winter. A thermal mass of sorts ... if I get the opportunity to build again ...will pour another slab.
Lastly - my Rx is to do the foundation (whatever method you choose) correctly - and reduce / eliminate the risk of your early reference to "leveling".
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