Portable building foundation questions

[Kris Cook]

This video for conduit bending was helpful to me.

https://www.youtube.com/watch?v=5L5Kujr98Cg

[Steve Rozmiarek]

I didn't see a specific answer on making long skids from short lumber, apologies if someone already said this. Build them of from shorter pressure treated 2x, with joints staggered and PL400 adhesive. Minimum of three layers with at least 16" of distance between seams.

Back in the 1920's when my great grandparents settled in this area, most buildings were built this way on their ranches. They would move them periodically to reconfigure the homestead for whatever was needed at the time. Some of them still exist, most have rotted into the ground. Back then, they moved them with horses. The buildings that survived were used as a shed to keep whatever feeding equipment that needed to be used daily, out of the winter weather. After the war when my grandparents took over, they quit using horses and switched to little John Deere "caterpillars". Those little tractors were still in use on the ranches into the 90's, and their use for feeding cows remained the same throughout their 50 plus year service life. During that caterpillar era, the little shed became the "cat house" that the caterpillars were stored in so they would start better in our rather extreme winter. The sheds would still get drug around when I was a kid to whatever valley cows were being fed in. One thing that struck me was the number of varmints under their floors when that shed started to move away. Snakes, mice, moles, possums, coons, etc. I never saw rattlers, but grandpa had a story about moving one and coming across hundreds of them under one. Point is, make sure the creepy crawlies can't make a comfortable home under it.

[Zachary Hoyt]

Thank you very much, that's very helpful. I have built and moved small buildings on skids here over the years for similar reasons to what you describe, but I haven't had to move them that far. I have never done this with anything bigger than a small shed, so the skids were always made from full length boards. I had been figuring on 3 layers of 2x6 per skid, but I hadn't thought about the PL400, that is wise. I'd figured I could stagger the joints 4 feet, and use deck screws to hold the boards together. I'm still wondering if I should make 4 or 5 skids for a 14 foot wide building. I'm always tempted to overbuild, but on the other hand it's more money and time.

[Jim Becker]

I didn't see a specific answer on making long skids from short lumber, apologies if someone already said this. Build them of from shorter pressure treated 2x, with joints staggered and PL400 adhesive. Minimum of three layers with at least 16" of distance between seams.

I agree with this. In fact, this is the preferred method for the posts in modern post frame construction to be made, the only difference being that in that case, just the lowest portion is made from PT. Laminated skids will be strong, resilient and likely much straighter than trying to source really long ones milled directly from a tree.

[Clark Hussey]

I recently had a Tuff Shed, 16X30 shed built. With a barn style roof. They built the floor with galvanized Steel 2X6s 16” on center. The roof height is 15’5” giving me plenty of storage space

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[Zachary Hoyt]

Jim Becker, that's true, and it's especially hard to get overlength PT lumber since it has to be able to fit in the tank or whatever they use to treat it, I imagine.

Clark Hussey, that looks very nice in there. I've thought about a taller roof like that, and have not yet decided if the potential ability to move the building in the future is a good trade off for not having much upper storage space. Luckily I've got all winter to think before having to decide.

[Clark Hussey]

Zachary, nothing like those lake effect snows you get out there. We have had about a foot here so far and it’s all melted. I love the extra height just to be able to stand projects up and move them.. storage is an added bonus.

[james glenn]

Since you want to keep this long term, I will offer the following:

You should use galvanized bolts rated for pt wood and thru bolt the laminations with the PL400 on the skids. Screws will pull and move eventually with water saturation, not to mention if you move it, the screws are weak in general unless they are structural Timerlocs.

Use pressure treated plywood on the floor as well, it's worth not having to deal with the aggravation later to replace.

Make sure the gravel doesn't have any large stones in it, and make it deep (10inches plus). Pack the gravel hard in 3" lifts as well with a tamper and make it wide enough so the edges don't erode, or use something to keep them in place. You only need a few inches raised above grade though.

I live in NY too, and the frost will move the building trust me. That size will then allow it to sink slowly over time during thawing, so the more gravel and harder it is, the better. I have to lift one of mine every 4-5yrs because I was in a hurry, but it's only for farm tools so doesn't matter.

[Zachary Hoyt]

Thanks, that's helpful. I can see the advantage of bolts. I will have to see if the frost bends or tilts the building. If it just goes up and down I don't mind that. It's all an experiment in some ways, as this is bigger than anything I've built before on this kind of (non)foundation.