Perfect Off-Grid Cabin Foundation... Cheap And Easy

So you want to build an off-grid cabin in the woods, but the foundation can be the biggest hurdle. A conventional foundation is going to require excavation and gravel work, concrete footings, rebar, block, cement trucks, heavy equipment, and for a lot of small cabins that's just not an option. So today I'm going to walk you through a simple post style foundation that is infinitely adaptable, very easy to build, it's very rigid and sturdy, anybody can do it. It's going to get you out of the ground and ready to build with the least amount of money. My name is Dave Whipple, you're watching Bush Radical. Today we're going to start a cabin building project in the middle of Alaska. I've owned this property for several years but there's nothing on it, nothing permanent anyways other than an outhouse I built earlier this spring. But today we're going to start a cabin foundation, 16 by 20. The foundation is a post style construction which has become one of my favorites, but first we need to talk about orientation and get this site cleaned out. So we have this spot here, we've got a nice big spruce, we've got this area here where there used to be huge spruce trees and there's a giant pine cone midden here, and then we've got this stand of black spruce over here. And I think the idea is going to be something like that, but I may have to turn it kind of based on where the morning sun comes up. For right now there's a whole lot of clearing that needs to be done to get this site ready and I may have a couple different options of how to fit this cabin in, but the spot itself is really nice. It's got good views pretty much every direction and if you want to see the morning sun in the front of the house, underneath the porch, it needs to go this way. And if you want the afternoon sun, it needs to go this way. I may put a porch on the front and the back so you can always have a shady option too. And one of the things I love the most about a post style foundation is you don't break ground. There's no excavation, there's no gravel work, there's no concrete work, there's no backfill, there's no need for heavy equipment. And when you're done, I've said this before, it looks like the place has always been there and that's generally what I'm shooting for. I want a building project to look like it's been there for 50 years, not like an area that's just been bulldozed with a new little McMansion in the middle of it. I want to sit in there and have charm and character right from day one. So we're going to clean out this site and the biggest problem on this site is there is 45 billion spruce cones. The squirrels have been living in a tree that doesn't exist here anymore for 300 years shelling pine cones and now there's a Mount Everest of spruce cones right in the middle of this building site. I need to get rid of all that. Ironically you would think it'd be a fire hazard but I've tried burning these spruce cones and they just don't like to burn. They'll smolder but they're really not as flammable as you'd think. I also got to remove as much of this stump as I can because when I start digging in the holes for the posts if a post lands where the stump is I'll have to take it out then and I may have stuff in the way. I probably took 30 trips with this tarp hauling as many spruce cones as I could at one time and dumped them on a brush pile. Then it took a lot of time to clean out all the dead wood too because there was quite a bit of that. Now the site looked really good to start with. It didn't look like it needed much clearing but it turned out I was wrong. I spent hours and hours cleaning out this site and it didn't look like it needed much to start with but it did. Also there was a whole lot of decaying wood from trees that had fallen down a long time ago and there I just built a new midden for the squirrels. They can live here now. I think that's about right. Site looks good. Okay so here's our spot. This is kind of the idea. You've got this large spruce here. You got this stand of black spruce over here and I can either set the cabin in like so right there and you'd have this view. Thin these trees out quite a bit. It would be quite nice. It's a very lovely view. Problem is this is north roughly and if the cabin's sitting like this you're going to be in the shade on the porch almost all the time. Right there's the sun and the porch would be sitting like this. Sun comes up this way. Porch is in the shade. So what I think I'm going to do, I think I'm going to put the cabin this way so that the porch faces to the east. So you're getting all that morning sun and it's going to be backed up against the stand of spruce back here. Later on I may trim out some of that spruce and put a porch on the back. Then you'd get the morning sun this way and you would get the evening sun on the other side. I'm going to start by trimming out just enough of these branches so I can work in this corner, but not too many. I think that will be the back wall roughly. So it kind of takes this opening, kind of runs this cabin in kind of a kitty corner angle in this spot and you get nice morning sun that way. Now that we've got land clearing out of the way and we've got our orientation figured out, we're ready to put in our first post. Putting in the first post is always the most fun because you can put it anywhere you want. All the other ones have to go exactly where they're supposed to be and they all depend on this very first post. I like to buy 10 foot posts. That will give you two five foot six by sixes out of each post. That'll get you about a foot and a half out of the ground and about three and a half feet into the ground, which I think is about right. When you get a post set like this, you want to keep checking it one side to the next, one side to the next, as you're tamping it down. If it's just a little out of plum, you can really tamp one side, sputter it in really good, put a little bit of force on it and you can true it back up. This one needs to go that way a fuzz. We'll spend some time on this side. Now all pole barns are built pretty much this way. A lot of times people will put a concrete footing at the bottom of the hole. Sometimes they'll fill the entire hole with concrete. Sometimes they'll treat the post with an additional preservative like tar. Do whatever makes the most sense to you and what you feel is the best practice. So when I ran out the tape measure, I put it where I thought it was in parallel with the edge of this post and then I put this spud in place. Now I'm siting it just to make sure. Now we're going to dig on this side of the spud we put in the ground. You can see that this lines up really good. Now we'll dig in that second hole. Make sure we got our post perfect with our tape measure and we're ready to set our first rim joist. I'm just setting a nail underneath this board. I want to make sure it's in the right spot before I hard nail anything. That looks about right. I run out and double check it in the center to make sure it's level and I can take it with a screw. I'll hard nail all this later. Now we have two posts set in. We've got one rim board on and those two posts are in the perfect spot. 19 foot 9 inches from outside edge to outside edge. The additional three inches is the rim joist that's going to go all the way around. Now we need to find our corner and dig our corner post hole. I've pulled square three times now, put the stake in there the first time, the spud bar, and pulling square is a lot like reading a compass. You gotta trust the compass. If your math is right, that's where the hole goes. The lay of the land sometimes, just the just the way things are set, you might get to the corner where the corner is supposed to be and it doesn't look right and then you go back and check your math and you come back and you're like yeah the math is right and you pull it and you're like well that's where it goes. This morning it was kind of a little dark and cloudy and I don't know that makes a difference but I pulled square and stuck the spud in. I'm like it doesn't look right. So I went and head launched and checked my numbers and it's the right spot. I don't think it's an exaggeration to say that the third post you set in a post style foundation is half the job. We're going to break that down in just a minute but it's a good thing to keep in mind. First two are easy, the third one's the real chore. Everything else falls into place. Let me tell you why. Okay the corner of that post 25 foot 3 and 8 and that's my diagonal. So I know the diagonal is right. I know this side is right because I set a board in it, tacked it in place. I also know that as it sits right now, plumb both ways. Every time I do one of these post foundations like this, the first post you just sink it you make sure it's plumb and the way you want your building to set because it's a six by six, you make sure that it's turned so it's lining up. You don't want it cattywampus because it's really difficult to turn once you pack that hole. But if it's in line, you know if it's square the way you want it to be, it's in the ground far enough and it's plumb both directions, it's good. The second one's pretty easy. You pull off it if your number is right and your post is plumb both directions, pack it in and it's good. But the third one is always the trick. The third post has to be the right measurement, which is easy to set with a board one direction, but then it also has to match the diagonal and it's got to be plumb both directions. So the third post is always the trick. But once you have the third post set, the fourth one is very easy to get in and then we can put the rest of our rim joists on. I like to just tack them into place and triple check them with a good quality level. Once I know that they're all level, we can go around and we can nail them off good and hard. If all your numbers are perfect and your square is good, trim off any excess rim joists on the corners and we're about done with this part. So now we have all four posts in and we've got them packed. They're plumb both directions and we know that they're square corner to corner. So the building is square. Now it's time to do a layout. Now layouts are very basic. They're very simple, especially for a floor. You're not compensating for windows. You're not trying to figure out where a doorway will land on a layout. On a floor layout, you're just laying out either 16 on center, maybe 12 inches on center. If you're doing something special, generally 24 inches on center. Now for this floor, we're going to do 24 inches on center, but this is a long span for a 2x8 floor at 24 on center. It would be like a wrestling ring. It would be really spongy. So we will set another row of posts in the middle and we'll put two 2x8s sandwiched on those posts as a girder to hold the center of this floor. That way the floor will be nice and rigid. Now we're laying it out so that our rafters land the center of the rafter on the two foot mark, on the four foot mark, on the six foot mark. So why is the layout X amount of inches on center? It's just because of plywood. That's all there really is to it. Plywood's four feet wide, eight feet long. Every sheet's exactly the same. And what you want is you want the very edge of the plywood, the end of the plywood sheet, to land right dead center in the middle of a floor joist. So when we do layout, we're going to start right from the corner. We're going to go to our first layout mark, which is two feet. So we're going to go two foot, three quarters of an inch. And on this side, we're going to go three quarters of an inch short of two feet. That way, if we have a seam in our plywood, it's going to land right in the center of this floor joist. We're going to do the exact same thing here at the four foot mark. Same thing here at six foot, eight foot, ten foot, twelve, fourteen, sixteen, and eighteen. Now one thing to keep in mind is to make sure that there's some tension on your tape measure. You might bump it or wiggle it, or if you move the tape measure just a fuzz, you can actually get off of your corner. And that's going to throw your layout out. Make sure that there is tension on that tape before you make your marks. Now you could also do a layout 16 inches on center. Just depends on what you want to do. 16 inches on center, you would go 16, 32, 48. And there are special marks on your tape measure for a 16 inch on center layout. But I like 24. 24 is simple. Now we're going to put in two more posts. Two more 6x6 posts. We want them to be spaced equally. So we're going to measure from the inside face of our corner 6x6 down to the other inside face of our corner 6x6 on the other corner. Then we're going to take that number, whatever this span between those two inside faces is, and we're going to divide it by three. Because we're going to have one post, which means there's going to be one gap right here. To the next post, there's two gaps. And from this post down to the corner. So that's three spaces between the posts. So we're going to divide this measurement by three. And that measurement is 225. Divided by three, seven. Three into fifteen, five. 75 inches. Unlike dimensional lumber, these posts are actually a true six inches. So we'll make our measurements. Make our mark. And this is actually going to be the center of the post. So what we're going to end up doing is we're going to go three inches on one side and three inches on the other side of this center mark. Make our marks and that's where that post is going to go. Truth is, the way this foundation goes together, it's not hypercritical to get these perfect. But you know, it's just a good idea to make sure that they're as close to the same span, one post to the next, as possible. And from there, it's just back to digging in posts. Which is not a lot of fun, but needs to get done. Check and plumb both ways. Also, sighting down that rim joist. Make sure you're not pushing the rim joist out. You can always tell if there's a gap between the post and the rim joist. But if there is no gap, you may be shoving that rim joist out. So just keep an eye on it. Now that all of our posts are in on the sides, we need to put a run of posts right up the middle for our beam. Now this wall is 16 feet. So we're going to go down to the middle, which would be eight feet. Make a mark. Then again, we're going to go three inches on either side of that mark. Because that eight foot is the center of our post. Three on either side, that's where that post is going to sit. I know a lot of this is probably self-explanatory. But somebody's always going to ask me a question if I don't put the information in there. And of course, ignoring everything I tell you is a good option too. Because a little foundation like this is very simple. And there's a thousand ways to do it. But I'm not going to tell you you're doing it wrong. One of the biggest problems in the world today, in my opinion, is the terrorist reign of experts. Where you only have one approved method to do anything. This foundation is going to get the job done just as well as any other. And being 50 years old, I'm sure it's going to last me the rest of my life. And what I really want, is I want a little cabin in this spot. I don't want a degree in engineering. And I don't want to hire some architect to come out here and waste my time and money designing something that's quote-unquote industry standard. I don't need that in my life. Not to mention the access to this site is kind of difficult to get to. So you'd have to develop a drive in here quite a bit to get heavy equipment and concrete trucks in. And I don't want it to look like that. I want it to look like it's been here. After digging in all those posts and setting them, with that string line, I've been able to mark level across all the posts of where I want my beam to go up the middle. Now let me explain this beam just a fuzz. I kind of got an idea what I'd like to do. So this is where the string was. And this is going to be the bottom of the floor joist. But underneath of the floor joist, I'm going to screw on a 1x4. It's going to make a little ledge on both sides of that floor joist to set the plywood bottom on. That way I don't have to get up underneath the floor to insulate it. I can insulate it from above. It'd take five minutes to explain that. Here in just a couple minutes I'll show you exactly what I'm talking about. But right now what I'm doing is just making a 90 degree mark on all of these posts because we're ready to cut them all off flush. Now the only thing to really keep in mind when you're trimming off these posts is they can be just a little low, but they cannot be high. Otherwise they'll be holding the plywood up from being nailed down tight to the framing. We don't want that. On this back wall you can see there's a little crown in that board. Now before I cut those posts I need to take that out. So I'm going to tack a nail in, put a knee on that board. Pretty high tech here. Nail her off and then I can cut the rest of those posts off. Of course I'll sight down this board to make sure it's perfect before I do the trimming, but we're ready to go trim those off and be done with this side. Nice. Now one thing to keep in mind with this style of construction. The wall itself, when you build the wall later on, it's going to be sitting right on top of these posts. So the floor system is not taking the weight of the building itself. All that weight is sitting right on the posts. Just make sure they're nice and true and that there's no bumps when you put the plywood on. You can see the teeth just barely scuffing the top of that rim joist. That's about right because you know you're down to it. You don't want that high. It'd be okay if it's just a fuzz low. Chuff it down with a saw if you need to. That looks about good to me. I'm cutting four 2x8s at exactly 20 feet. These are going to be my inside ledgers and the beam down the center. Once I have my center beam boards in place and I've got my ledgers sitting at least inside of the building where they need to go, I can start putting my 1x4s on the bottom of my floor joist. Now this might not make a lot of sense to just say it, but as soon as you see the process, you see what the point is, it's going to make a ton of sense. I'm going to cut all of these at 15 foot 9 inches because they need to go inside of this 16 foot span. They're going to be about the same length as the floor joists themselves. Maybe just a fuzz shorter because I don't want them to get in the way. Now on the end, I'm taking a block of wood and scribing a line 3 quarters inch from the outside edge. I'm going to put screws in it. Doesn't make any sense at the moment, but it'll make perfect sense here in just a second. Once I get this 1x4 filled with screws, I'm going to put it underneath the edge of the building and then screw it off to that end rim joist. And it's going to act like a little tray so later on I can drop a plywood bottom between the floor joist and the floor joist next to it and the rim joist on the end of the building and I can make a floor from the inside to hold the insulation. I don't have to crawl underneath this stupid thing and try to hold plywood up and screw a plywood bottom to this foundation. I'll be able to drop the plywood bottoms in just like drawer bottoms. There, that looks fantastic. You get the idea. Now I'm going to take the ledger board. That's the second board that's on the inside of the foundation opposite the rim joist. I'm just going to tack it into place. Not hard nail it, just throw a couple nails in it just to hold it in place. The reason I want these ledgers in place right now is I'm going to need them to set my floor joists on. Kind of just like a work rest as I put them in place. I'm going to make a mark on this little scrap of wood and I'm going to use it as a gauge so when I put these 1x4s on the bottom of the joists, I can be sure that they're sticking out the same amount on both sides. That's about right. As I go down this 1x4 and screw it off, I'll check it every now and then to make sure that it's dead center of where it's supposed to be and I've got the same amount sticking out left and right. Then we'll just roll this guy over and put it in place. It's right on our layout mark. Nice and flush on the top. My brother Ryan built this style of foundation years ago on a little cabin project he did and I loved it. I thought it was great. It's so easy to put this type of foundation anywhere you want. You can put it way back in the woods, carry it all in on your shoulder. It's a great way to go. I've been using it ever since. You know I have to say one of the best things you could possibly have on hand to make this job easier is bug dope. Lots of bug dope. This year I finally broke down and I bought one of those thermocells that sit on top of like a tank of fuel and I got the big tall tanks. You can buy these at Walmart. They're right next to the Coleman Camp Fuel. Just the butane cylinder stove tank thing. I have yet to run that out of juice. I've been fighting off mosquitoes for months on end and it just keeps going and going and going. I think they say 300 hours with that big butane tank on one of those thermocells. Best money you can spend. Now that ledger is holding this joist up but it doesn't mean that it's flush. So make sure you check every single one of these and make sure that they are flush at the top before you sink that first nail. That looks about right. Once you take that first nail of course make sure it's plumb to the line and stuff the rest in. Once all the floor joists are nailed off I'm going to pull this ledger up tight. What I'm doing right now is I'm just setting a nail underneath of the ledger. I'm going to pull the other nails and that way I can get it tapped down so it's in the perfect place. Get it nice and true on the end. Oh that's lovely. Set a nail and I can really get some upward pull with this pry bar to get it good and tight. Now this might seem a little backwards to nail this ledger board off last but the fact is there's always little discrepancies in these 2x8s and if you nailed the ledger off completely solid all the way down before you put the floor joists in place, well if you got one floor joist that's a little wider it's going to be sticking up higher than the outside rim board. So I want them all to be flush and then I'll pull the ledger up and get it nice and snug. Once both outside ledgers are nailed off hard I'm going to pull up these two center beam 2x8s. On one end I'll use a ratchet strap. We'll get all the slack out of it get it up as high as we can. Now on the other end we'll pull them up and just set a nail underneath just to hold them in place. The purpose here is that way we can adjust them so that they're perfectly true on both ends. Snug this guy up get them right up tight. Nice we like that. Once they're all nice and snugged up and they're trued up on the ends we're ready to start taking them. I'll hard nail the ends first then we'll go back to the center once we're done there and kind of pull them up with our pry bar just to take any of that slack out. We don't want to force a crown by reefing on the bottom of that and pulling them up super super tight. We just want them to touch. We want them to be in contact with the floor joists. That way when the floor is loaded up with the plywood decking it's going to sit on there just perfect. Now some of these joists have a bit more crown and they're not even touching. Some of these other ones like this one are nice and snug. Kind of just got to find a happy medium because there are differences in the height just slightly and it only takes a little bit. You don't want to pull up on that center girder so much that you that you're putting more crown into already crowned boards. Just get it up there where it's touching. Now comes my favorite part just nailing everything off. Anything that needs a nail that didn't get a nail just go around like a trained monkey and drive all the nails in. Now I love this cabin foundation for so many different reasons. Number one all of it can come on a pickup truck. You can bring it all in on the pipe rack of a pickup truck or with a trailer. You're not going to need heavy equipment. You're not going to need to get a concrete truck to the site. You're not going to have to bring in gravel or do any excavation work. A lot of people would like to tuck a cabin way back in the woods in an area where there isn't even a drivable trail. Every piece of this foundation can be carried in on your shoulder. All the tools can be brought in on your shoulder. You're not going to mar up a site with excavators and skid steers and dozers. So this is basically a foundation you can put anywhere. You don't need good access. You don't need expensive equipment. You don't need to rent anything. It's just kind of a perfect little solution for the problem of how to build a cabin foundation. Thank you guys so much for watching. My name is Dave Whipple. You've been watching Bush Radical. Be Radical, eh? See you soon.