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Small Cabin Forum / Cabin Construction / Foundation for 16x20 cabin
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adksnorth
Member
# Posted: 20 Nov 2019 11:27
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Hi, new to the forum. Wondered if anyone could weigh in on the approach I'm considering for the foundation for a 16 x 20 cabin in the northern adirondacks.

Planning on three parallel beams, eight feet apart, 20' long apiece, each made up of six 2 x10s, 8 foot lengths, sandwiched together (staggered), to make beams of 9" x 9 1/4" x 20'.

Each beam will rest on foundation blocks set 5' apart, starting at the ends.

Between the beams I'll run 2 x 4s 2' oc, not for the floor framing, but for plywood that will be under the floor framing, so plywood on top of the beams and 2 x 4s. This is to keep critters from getting into the floor framing and insulation.

On top of all this, I'll put the frame for the floor, which will be 2 x 6 16" oc, and insulation for the floor.

Any thoughts?

Thanks in advance - great forum.

Brettny
Member
# Posted: 20 Nov 2019 13:51
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Pull your main beams in about 12in on each side to keep them away from the weather and if those beams are close to the ground make sure there PT. The 2x4s under the the floor arnt needed. Use something like a 2x8 floor joist and cover the bottom with plywood. The false floor under everything isnt really needed and could end up being a mice highway.

Blocks for northern climates really suck or take alot of site work to get to not move in the frost. With the way your framing your a few sono tubes, a pallet of concrete and a hand full of 6x6 posts away from a real frost free foundation. If you wanted to raise the main beams up enough you wouldnt even need PT lumber for the main beams.

Also call around to local lumber yards i bet you can get a 20' piece of wood alot easier than you think. Making a 20' beam with 8' lumber is a bit crazy. If you do endup useing 8' boards make them break ontop of the blocks/6x6.

Brettny
Member
# Posted: 20 Nov 2019 13:54
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Also 6 2x10 for a carrying beam is a bit much. Your only spaning 5' with it at a time. O and dont put your first block at 0' and the last one at 20' pull them all in 1' so everything ends up being under the building and dry. Rain on concrete will splash.

adksnorth
Member
# Posted: 21 Nov 2019 09:28
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Thanks very much for the response.

I'm going with the blocks instead of sono tubes because of how rocky the ground is - not sure I'd be able to get straight lines for the tubes where I want to put the cabin. Would also need to dig it by hand, pretty deep to get below the frost line.

I appreciate the advice on the splashback, I'll adjust for that.

Going with 8' material as anything bigger would be a major chore to hump to the site.

Thanks also for the info on the beams...been looking at tables to figure out how thick I need but it's pretty tough to figure it out from those, wanted to get feedback from people who are actually building and not just the tables.

Thanks again!

Brettny
Member
# Posted: 21 Nov 2019 11:29
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Your going to have to build this to code in NY so you should really be asking the local building inspector. Blocks may not even be allowed.

ICC
Member
# Posted: 21 Nov 2019 15:01
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Listen to what Brettny just said there. My understanding is that everywhere in NYS is covered by building code as well as sanitation rules. I do believe but could be wrong, that there is a special set of rules for a hunting or fishing cabin. If that is applicable that will come with a bunch of special restrictions too.

Before doing any work or even much planning I would suggest checking with the local authority having jurisdiction over permits. There is a topic here someplace from a few years ago. A couple in NYS started a build using non-conforming methods and got caught after they started.

adksnorth
Member
# Posted: 21 Nov 2019 16:04
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Thanks fellas, I'll do that. I spoke with him last spring, and gave him a general idea of my approach...rough size, not on grid, etc. He said it would be classified as a "shed" and wouldn't require an inspection, just a $25 fee to file the paperwork. Now that I'm getting more detailed on the cabin plans I'll follow up with him and make sure. Definitely don't want to get started on something that they'd shut down.

adksnorth
Member
# Posted: 21 Nov 2019 16:07
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Not going to start building it until late next spring, after the snow is gone and the ground has dried out...

Princelake
Member
# Posted: 22 Nov 2019 07:02
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I'd go with atleast 2x8 for floor joists. What's going under your blocks? Are you digging and pouring pads for the block to sit on? Also putting one or 2 layers of plywood in your beam with make it even stronger. Good luck! I'll be out at my place this spring starting to frame to!

Brettny
Member
# Posted: 22 Nov 2019 07:14
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I also forgot to mention that if your in the Adirondack park you have to get permission from the Adirondack Park Agency as well as your town to build any thing. Just because the town/county dosnt care what you build that dosnt mean the APA doesnt. Grid tied or not codes still apply in NY.

No where in NY is a new outhouse legal.

The APA is why we didnt even look at property in the Adirondack park. These are also all laws that i looked up before even thinking of going to see a piece of land.

adksnorth
Member
# Posted: 22 Nov 2019 07:48
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We're not in the park, just a ways outside of it. No new outhouses anywhere in the state? I don't understand why they would regulate to that extent. If you have a good sized, remote piece of land, past the town maintained roads, what difference would it make to them if you put up an outhouse? I see bumper stickers in NY sometimes that complain about the regulations and taxes, maybe this is the kind of thing they're referring to...

Princelake, I'm thinking 2x6s since it's a standard size for insulation, but why would you choose 2x8s? Interested in the pros and cons in your mind of one versus the other. I'm thinking I'll just dig down to the harder dirt and put a layer of gravel underneath, thinking a concrete pad may heave and crack over time instead of giving the way gravel would. What are your thoughts about this? Spring can't get here soon enough, good luck to you too!

Brettny
Member
# Posted: 22 Nov 2019 08:54
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Yes no new outhouses in the whole state. You need to read the laws, codes and talk to the building inspector before you plan any more.

2x8 over 2x6 because a 2x6 floor will be very bouncy, flex and not have the same R value as a 2x8 floor.

A gravel pad under blocks really wont do much since you wont be below the frost. In clay it will hold water and prob move with frost more. In that area of the state to get dry ground conditions your looking at around may.

We are further south near Utica. Il be drawing plans this winter and submitting them to the town. In late summer/fall we will break ground and get the sono tubes, main beams and floor joists in, then winterize it. This will give us a very good foundation that can be worked on early the following spring. Mosquito and black fly season is nothing to mess with around here.

adksnorth
Member
# Posted: 22 Nov 2019 09:34
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I did talk to the inspector last spring, discussing the approach I had in mind - size of cabin, no electric or plumbing, and I just checked my notes and see that at that time he also said no underground foundation was needed either, and he told me this approach would be fine, no inspection would be needed, just a $25 filing fee. He said people build like this around here all the time. So now I'm finalizing the plan that I will file along with the fee.

I hear your concerns about frost, but I see many small cabins and other structures around here sitting on blocks that have been around for a long time without sagging or other problems. Digging really isn't an option for me so I have to do the best on top of the ground that I can. My thought with the gravel is that it will allow me to level out the really small dips and bumps when I create a flat surface on the ground for the blocks, to lessen any stresses that could cause the blocks to crack. I'm not going to dig them down except for clearing a flat space because I don't want water to collect there.

I don't see how a 2x6 floor will be bouncy when the run of the joists will be only 8', and 16" OC. I could put more insulation in 2x8, but I'm not planning to be there in the dead of winter and I need to watch my costs.

Mosquitos and flies are tough up where we are too, especially in the spring and early summer (right when I'll be building!). I've seen some good reports from people who got screening that goes over your hat and down to your shoulders, so that along with long sleeves and work gloves should make it more bearable. You can find them on amazon, for pretty cheap.

One of the things with my cabin is that I'll be doing all the work myself (with my family), using power tools but no heavy equipment. So simple, small, and sturdy are my main goals, along with a careful watch on costs. We'll be there a lot in the three non-winter seasons, not much (if at all) in the winter. What are your plans for your place?

Princelake
Member
# Posted: 22 Nov 2019 12:49
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What about a post hole auger and do sonotubes?
And yes 2x6s will bounce.
Id buy 10' instead of 8s and cross them in the center. Even precut them to 9'. You want them to cross by atleast a foot.
For the outhouse dig your hole and build a shed on top and have a stall in there. Nobody will ever suspect it's an outhouse haha.

AKfisher
Member
# Posted: 22 Nov 2019 12:54
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Quoting: adksnorth
I don't see how a 2x6 floor will be bouncy when the run of the joists will be only 8', and 16" OC. I could put more insulation in 2x8, but I'm not planning to be there in the dead of winter and I need to watch my costs.


Id listen to Brettny. 2x8s will stiffen it up, sure a 2x6 will span the 8', but the for the extra buck or two id go bigger and better. Larger joists may also help relieve some of the heaving you may have since you won't have sonotubes into the ground.

I used 2x10 joists 16" OC that spanned 7'. I also have an R30 floor insulation. My foundation is 16x24.

spoofer
Member
# Posted: 22 Nov 2019 17:20
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My cabin is in the tughill area of NNY. lmost all the hunting cabins old and new are still using outhouses. I just put a new one in a few years ago. Hired a contractor to dig a 4x4x4 hole and put a "cadillac" of all outhouses there.

MtnDon
Member
# Posted: 22 Nov 2019 18:00 - Edited by: MtnDon
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From something found by Google

I added the bold face...

"(m) Hunting and fishing cabin and hunting and fishing and other private club structure means a cabin, camp or lean-to or other similar structure designed and used only for occasional occupancy and primarily for hunting, fishing and similar purposes that:
(1) is a one-story structure but may include a sleeping loft;
(2) is built on posts or piers and does not have a permanent foundation;
(3) is served by a sanitary pit privy or chemical toilet and does not have a conventional, onsite wastewater treatment system;
(4) does not have pressurized or indoor plumbing (this prohibition does not preclude a kitchen sink with appropriate grey water leach pit); and
(5) is not connected to any public utilities (such as electric, phone, cable, water or sewer systems)."


How is everyone?

naturelover66
Member
# Posted: 22 Nov 2019 18:55
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Nice to see you here Mtn Don. Happy Holidays !

Brettny
Member
# Posted: 22 Nov 2019 20:19
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Quoting: MtnDon
built on posts or piers and does not have a permanent foundation;

I asked my local building inspector about this. He said sono tubes are not a permanent foundation.

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