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Future Cabingirl
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# Posted: 18 Oct 2013 09:53pm
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*This is a husband and wife team post*
We recently bought some remote property, 10 wooded acres in northern Michigan. Its down a decent two track, no electricity, hand pump well. We are getting close to the building phase of our first small cabin and were hoping to get some advice/fact checking/help.
Here is our construction plan: Skid foundation on blocks. The blocks will be 4x8x16 solid concrete stacked side by side and 2 high. Not entirely sure how many "block piers" we will need. The cabin dimensions are 12x30 sitting on 32 foot skids. We were thinking of 5 block piers per side. The skids will be 2x8 laminated 4 wide, or possibly 2x10 with reliefs cut in for the floor joists (good idea?). Both floor joists and skids will be from PT lumber.
For the floor, 2x10x12'. Do I build this in sections? (12'x10', three times?) or do I just put a board spanning the joint of the boards as needed? For insulating the floor I plan to put 2x2 along the bottoms of the joists, and then put down flashing and then put down foam board insulation and then subfloor. 16 inch spacing.
For the walls, 2x6x10's. We are planning on a story and a half. Not enough loft for jumping jacks, but we want to stand up. For the floor joist of the loft, I was thinking of 2x8x12s on 16in centers and then screwing them to the wall joists. Is that a bad idea? In my head it seems great.
For the ceiling/roof. 2x8s, birds mouthed, metal tie down/connectors, 12/12 pitch. At least one foot overhangs on each side. Ceiling and wall insulation will be fiberglass rolls.
We are getting close to a getting started point and need some input. Please feel free to tear this plan to bits, correct, set straight and otherwise let us know whats up.
Some more specific questions. Do the skids sit on the very outside of the structure or inset about a foot? Should I cut reliefs into the skids for the joists?
I realize this is quite long. You probably can't tell from reading this, but we aren't professional builders. Hopefully you are. PLEASE HELP. Thanks again for all the advice already on this board... you may recognize some of our building plans from ideas already on here!
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MtnDon
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# Posted: 18 Oct 2013 10:14pm - Edited by: MtnDon
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Quoting: Future Cabingirl possibly 2x10 with reliefs cut in for the floor joists (good idea?)
No. notching reduces them to the size of the notched area. Notch 2 inches into a 2x10 and that will be as strong/weak as a 2x8. Maybe, maybe not. Notching is similar to ripping in that it cuts into wood that can no longer support loads; might as well use the 2x8 and save the cost of the 2x10 as the 2x10 will be weakened by notching/cutting into. (Most often when a 2x10 is ripped down the grade drops. Long explanation as to why but no time to explain right now. Has to do with visual lumber grading rules.)
Quoting: Future Cabingirl 32 foot skids. We were thinking of 5 block piers per side.
= about 8 feet between supports. A quick look at my tables shows that for an 8 foot span 4 - 2x10 or 3-2x12 would carry the load for a 1 1/2 story if the snow load was 30 psf or less and the cabin was no wider than 20 feet. I didn't notice the width mentioned.
... taking a step back... northern Michigan. Cold, cold winter = fairly deep frost level. The best foundations need to having the footing (poured concrete) as deep as the frost depth, not blocks simply stacked on the ground. Depending on what you expect the longevity to be and how much you want to avoid possible freezing related problems and movement you might want to rethink the foundation.
No time for going through the floor, wall, etc for me right now. G/L
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Just
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# Posted: 18 Oct 2013 10:40pm
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Your plan may be a little to big for a concrete block foundation . in MICH. you will have lots of frost to deal with. at 30 feet long it's hard to keep it from twisting the cabin .If you want to go that big it may be worth putting in a below frost line foundation..
A 16 x 16 or even a 16 x20 would be better on skids .You can build a 16 foot wide building on 2 skids if you place the skids 1 foot in from the edge leaving a 14foot span with 2x10 's . that would also give you a bit more head room in the loft . sounds like your going to have a great place "just" my thoughts
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OwenChristensen
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# Posted: 19 Oct 2013 08:46am
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Yes , what they said, I build on skid in frost country and that length would cause me concern. What type of soil do you have? Good drainage gravel? Not a problem. Clay, wet? watch out.
Notching the beams over the block is fine, as the strength required is between the blocking. Your 2x10 floor joist are one size bigger than you need , if on 16'' centers. Have your beams set in from the sides by a foot or less, it really firms up the floor. The 2x8's for loft joists will work. If I were doing it, I'd notch a 2x4 ledger into the wall studs and set them on that.
As far as the long building on skids, If you want you can dig four or five foot post holes and use treated 6x6's and backfilled with sand or gravel.
I don't like to go 8' span on the posts. I've seen triple 2x12 treated sag between posts. Strange right,? there wasn't even a load on them. It's just that they are wet and can bend under their own weight. When building those beams, you can see that they have a slight crown to them.
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Future Cabingirl
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# Posted: 19 Oct 2013 09:28am
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The soil we are building on is pure, pure sand. Seems to be really well drained. If 12x30 is long for the sqft, would the 16x20 recommended above be ok. My concern with making the cabin wider was adding complication to the roof and floor. We don't want to dig the foundation in because we may look at skidding the cabin to a different spot on the property after we have cleared everything.
Would we be better off putting the skids on gravel instead of blocks? Also we would like the cabin to last a good long while, but if it lasts twenty years I would be more than happy with that. Twenty years ago we were just starting elementary school, so we've accomplished a lot in that time.
Could we remediate the problems with the 30ft length by using jacks to keep everything plum and level once a year?
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OwenChristensen
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# Posted: 19 Oct 2013 09:36am
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I think you'll be fine, but yes a little shorter and wider would be better. Full beam contact with ground is best. Sometimes block pads can be pushed into the ground. That won't happen with full contact. getting them level is a lot of work though. 12x 30 is also hard to do interior layout. I think you can build big beams, bevel the ends and set them on the sand. Pulling the building off of blocks is a problem of it's own. Do a lot of cross blocking between those beams so they don't move when being pulled.
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Martian
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# Posted: 19 Oct 2013 09:49am - Edited by: Martian
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If you plan on dragging it in the future, plan for it! Like Owen said lots of cross blocking, and you might even consider running a cable harness while you're building the structure.
Tom
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Future Cabingirl
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# Posted: 19 Oct 2013 10:25pm
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So if we put the skids right on the ground, do we take the top soil off first? Should we trench and then gravel? I do plan to use gutters to help keep water away from the base of the cabin. Also, if we don't cut notches into the skids, what is the recommended way of attaching the floor joist to the top of the skids?
I guess I would prefer the 12x30 if its doable, we have what seems to be a really great plan build around that already. I don't mind the thought of checking and correcting any twisting/unleveling in the skids each season, but if it will destroy the cabin then we can adjust our plans.
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OwenChristensen
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# Posted: 20 Oct 2013 12:02am
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Well if the top soil isn't sand, then yes dig it away. Sand should be as good as gravel for the skids to set on. I just toe nail joists to skids. On truly portable buildings I put blocks on top of the skids between the joists, at least on the ends. If you go 30' you probably won't see any movement at all on good drainage sand and if you do it might be several years to show. If you actually plan on releveling, then having the skids all the way out on the edge would be easier to work with.
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silverwaterlady
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# Posted: 20 Oct 2013 07:55am - Edited by: silverwaterlady
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Here is what we did long before we built,we set up a tent on different spots on our property and stayed in it for a few weeks. This is a lot easier in determining a good location for your cabin versus moving it.
We did not use gutters because heavy snow would slide off the roof and tear the gutters to shreds.
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Future Cabingirl
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# Posted: 20 Oct 2013 02:36pm
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We have been staying up at the property, so we have some good ideas about where we would like to put everything. We want the cabin to be mobile because we are thinking of moving it in the future, but it would take a lot of clearing to get there. And we are hoping to be up that way sooner rather than later. So put it on skids, stay in it now while we clear and build and plant and cut and ect, but then move it to a more ideal location in a few years once we've readied everything.
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PatrickH
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# Posted: 20 Oct 2013 08:25pm
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I think you should build what you want in the proper place,I have never heard anyone complaining about building a proper foundation but I know so many people that wish they would of done crawlspace/basement foundation.I know someone that just put in a walkout basement used it for 20 years then built the cabin later.
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