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rmckenzie
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# Posted: 1 Dec 2022 19:34
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Hi all,
I'm working on planning out a cabin on some family land in rural Arkansas. I've been going around in circles reading about foundations on here so I thought I'd go ahead and ask for some advice!
I'm trying to strike a good balance between getting something that will last but not overbuilding for such a small structure. Funds are limited but time is not. The frost depth here is about 14", and I am building on red clay that can get pretty wet.
Building on a hill, so I want to do a post and pier type foundation, with 6x6 wooden posts set on concrete footers. What I'm not sure is if it would be better to 1) dig down about 2 feet, pour a 16x16x8 type footing in the ground, and then place the posts on top of that and backfill or 2) pour the concrete up to grade and then connect the posts on top of that? In the second case, I worry about lateral stability, but I don't know how much good burying the posts the 16" in the ground is going to do either.
Thanks in advance for any thoughts on this, or any other advice on the best and easiest ways to get this kind of foundation in the ground!
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frankpaige
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# Posted: 1 Dec 2022 19:56 - Edited by: frankpaige
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Your going to enjoy this cabin! I hope you enjoy the process as well. Hard sometimes, but very fulfilling.
I did the post/pier foundation. Today I would have the slope leveled and build on that. While I have no no issues with my foundation. I believe it would have been less work and heartache.
I know there is going to be some great advice coming your way on what to do.
Wishing you the best.
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spencerin
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# Posted: 1 Dec 2022 23:54
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How much change in elevation from back to front, and side to side?
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JHunt
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# Posted: 2 Dec 2022 05:37 - Edited by: JHunt
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I live in North Alabama and built a 10x16 cabin on posts but decided to try something a little different. I dug down three feet and put a foot of gravel at the bottom. I had cut some 12 inch trees down the year before and cut them into five foot sections and let them dry. I then painted the with very VERY thick fence paint and then put them into the holes and backfilled. It is clay so it has settled pretty quickly and now that I have a cabin over the posts nothing gets wet. It was a pain to do but my little cabin sits on nine posts that have not moved an inch and being on gravel drain better than it on concrete. Just a thought.
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Grizzlyman
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# Posted: 2 Dec 2022 07:39 - Edited by: Grizzlyman
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I understand your lateral stability concerns..Was for me as well… I had about 3’ of elevation change over the various piers.
I can tell you that when done it is rock solid.
I poured up to grade, then filled concrete blocks and put j-shaped threaded rods into the concrete. To that I attached bolt-down post bases for the 6x6 posts.
Cross bracing is key to making it solid. Good luck!!
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Brettny
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# Posted: 2 Dec 2022 09:05
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For such a small building just put it on blocks and prep the site for good drainage. If you really have to put a foundation in just use sono tubes from the frost line right to the bottom of the skid if the ground is any where near level. Sometimes adding wood posts onto concrete just makes things more complex than they need to be
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rmckenzie
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# Posted: 3 Dec 2022 14:14
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Wow, thank y'all so much for the advice so far!
There is about 1' of elevation change along the 12' wall, and about 2' along the 16' wall. I also would love to have it be sufficiently elevated off the ground to avoid using PT for the floor framing.
JHunt: I love the look of this, and am glad to hear it has settled out nicely! I have thought about doing this in the past since we have plenty of cedar on the land that seems like it would be good for this purpose. Think it's too late for this project but might have to get some logs drying for the next one.
Brettny: I would love to avoid digging out a real foundation if it doesn't seem like it'll turn into too big a hassle down the line. The last thing I need is for anything to be more complex than tt needs to be! With the 2'-3' elevation change, would placing the 6x6 posts on a base of solid concrete blocks on the surface work okay? Or would you suggest building piers up to level using concrete blocks?
One last question: I'm planning on doing a 2x8 floor and hanging the joists directly off 2-ply 2x8 beams. Does 4 posts on the long side make sense as support for this type of frame?
Thank y'all again for all the help - I've never built much more than decks before but man I am excited to learn!
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Brettny
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# Posted: 3 Dec 2022 20:04
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Quoting: rmckenzie One last question: I'm planning on doing a 2x8 floor and hanging the joists directly off 2-ply 2x8 beams. Does 4 posts on the long side make sense as support for this type of frame
2x8 floor joists are plenty for a 12' span..but I would pull in skids about 12in on each side so your really spaning 10'. Useing 2ply 2x8 for skids will also be plenty but would use PT for them.
I have a 10x14 building with 6x6 skids, it's on concrete blocks right on the ground and I used 3 blocks per skid. Even after 3yrs the door opens like new. I'm on clay in the northeast.
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JHunt
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# Posted: 4 Dec 2022 07:06
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I will give you one more piece of advice after having built a 10x16 cabin with no experience but plenty of ability to think and do. Don’t let perfection get in the way of progress. There were catch moments that would make me pause. Putting up my own rafters alone, metal roof alone, cutting a hole in my water tight roof for a stove. You get the idea! And I would think on it. Plan. Watch videos. Read. And then just go up and do it. And it worked. Enjoy the process and can’t wait to see what you do. Good luck.
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spencerin
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# Posted: 4 Dec 2022 20:33 - Edited by: spencerin
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If you want to keep it simple, it seems like the simplest solution would be to place 6 x 6 concrete deck blocks on beds of well-drained, compacted gravel, and use those to support your 6 x 6 wood piers, with plenty of bracing to prevent lateral movement (as previously suggested). I would paint the bottoms of the piers where they sit in the blocks with a thick asphalt paint to prevent rotting. It doesn't get any simpler than that. There are other solutions, of course, but they increase in complexity.
Not sure why you don't want to use PT wood for the floor framing, but you should.....
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rmckenzie
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# Posted: 9 Dec 2022 17:06
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Thanks again for all of the great advice here!
I'm thinking I will build on skids after all. I've messed with the location some, and I think I will need piers about 1' high on the back wall and about 2' high on the front wall. I'm going to build these out of concrete blocks set on gravel, and then rest 2-ply 2x8 PT skids on top of those, set in about 8" off the walls and cantilevered about 3" over the end of the beams. Then I'm going to build the floor out of 2x8 set 16" O.C. resting on top of that.
One more question I had: I'm also thinking about adding a 5' covered porch onto the 16' side of the cabin. When building with skids like this that are below floor level and set back under the building, is this best way to build such a porch just to frame it as a freestanding deck with it's own supports sitting near the piers for the full cabin?
If I did frame it like that, what options are there for adding cover for the porch? On the main cabin, I want do a single slope roof going from a 10' wall to an 8' wall. Would it be best to also rest the porch rafters on the 10' wall? Or to attach them to a ledger board type thing tied blocking within the framing of the wall?
Thanks again for all the encouragement - hoping to get going this weekend if the weather hold up!
Quoting: JHunt Enjoy the process and can’t wait to see what you do. Good luck.
JHunt, thanks for this advice and encouragement! I'm definitely in it as much for the process and the opportunity to learn something new as for the finished product.
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frankpaige
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# Posted: 9 Dec 2022 17:22
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I believe in looking back. You will be happier on skids.
Have you considered? Not building a permanent covered porch? I certainly understand the porch/patio for the cabin. I just did not wish to go the permanent covered route. Snow load and cost for me. I did build the patio. Separate from the cabin foundation. I choose to use a sunshade. Hooks to cabin's eaves. Then two pole off the deck. Takes 10 minutes to put up on arrival. Now? If you were considering storing items there? There is that discussion. I did end up building the dreaded she shed for what I really do not use much. Also. I have no mosquitoes.
If your going to attach the porch to the cabin. I know you will receive great advice in that.
Keep a log of your progress. Always fun to go back and read.
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spencerin
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# Posted: 9 Dec 2022 22:24
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I feel like 2' of concrete block would be too unstable. Too segmented, and too narrow for its height. Just my opinion, and others may disagree.....
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Brettny
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# Posted: 10 Dec 2022 06:26
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You can use two side by side, then lay the next cource o0* from that. They also make masonry glue in a cawlk tube that holds better than actual mortar.
I have 2 blocks stacked on a 2in paver so I'm at 18" and its been like that for 3yrs. I just dry stacked them right on the ground.
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spencerin
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# Posted: 10 Dec 2022 13:42 - Edited by: spencerin
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Brettny, after I posted that, I thought the exact same thing. Paired 4 x 8 x 16s, with the next level up rotated 90*, with masonry glue. Great solution.
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Brettny
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# Posted: 11 Dec 2022 07:08
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I helped a friend remove a retaining wall that was glued together by him about 10yra prior with that masonry glue. We could get very few pieces appart. I was really suprised.
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rmckenzie
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# Posted: 11 Dec 2022 22:41
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Quoting: Brettny I have 2 blocks stacked on a 2in paver so I'm at 18" and its been like that for 3yrs. I just dry stacked them right on the ground.
Thanks to you both!! Started building today and did exactly this - it worked great and got everything leveled off. Hoping to get into building the floor up tomorrow!
One issue I did run into: when I built up the 2-ply 2x8 beams, one of the 2x8s was a little wider than the other, and so the beam sits a little off kilter on the blocks. Running a test joist across the two beams still seemed to sit level, but I want everything to be as strong as possible. Are there any best practices for evening out those two beams? My best guess was sanding or planing out the wide parts of the larger one.
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spencerin
Member
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# Posted: 12 Dec 2022 21:18
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Off the top of my head, use a circular saw to trim off that sliver of 2-by so it's flush.
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jsahara24
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# Posted: 13 Dec 2022 09:38
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Cedar shims?
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