I have some 4x4x8' PT for the skids. I was going to then put 5, 12' -
2x'4s spaces 24" OC atop those for the floor joists with an 8' 2x4 to cap off the ends. The load bearing walls will be along the 12' side. Is this OK? Or should I start with 12' skids and then atop those run 8' joists?
I guess the question is -- does it make any difference which side supports the load bearing walls? I have the 8' 4x4s, so I'm trying to use then vs having to buy 12' ones.
What are you using for the actual floor and what loading are you putting on it?
24" pitch is a bit wide, 16" centres are more usual, with 18mm thick T&G boarding for "normal", loading 22mm thick for heavier loading. For a workshop I would recommend you go for 22mm (all finished sizes)
My own shed is 6'x 6' with end supported 2x4, 16" apart and 22mm floor boards.
Stuart, Thanks. The flooring I bought was 3/4"-ish t/g. I'm seriously thinking to go 16" o.c. as it just adds 2 more joists. I made a chicken coop based on the same basic design and went 24" o.c. with 1/2" plywood. Chickens don't mind, but it's pretty spongy if you walk around. But primary question is does it matter which way the joists run? Right now I planned to lay down 8' 4x4 skids, then put
12' joists perpendicular to those. The load bearing wall will sit atop the 12' side walls -parallel to the joists (perpendicular to the skids). It somewhat seems like it would be better to put the load bearing wall perpendicular to the joists -- thereby having 8' joists, and then 12' skids. I already "have" the 4x4 PT skids, else I need to go buy 3 12' - 4x4 PT or possibly join together the 8' ones.
I would recommend using pressure treated 2X6 for floor joists, 16" OC. It won't be that much more expensive and your FOUNDATION will be sufficient for any future use of the shed, should you want to change its use from simple storage (?) to something more substantial, later. Don't skimp with your foundation construction, you'll possibly regret it. Now is the time to, also, consider possible future use, different needs/requirements, etc., not just your immediate use/needs. What might you be doing in/with the shed in 3, 5 years from now? Invest in the surety of the foundation, not just in what will be above the foundation.
Sonny - thanks, generally agree, but 2x4 flooring I think will be sufficient. What I most need to know now is whether the layout of the load bearing wall on the joists is OK. As-is, I was planning four
4x4 8' skids, then 12' 2x4 16" o.c. joists perpendicular to the skids, and then the load bearing wall along the 12' length, which means the wall sits parallel atop the outside 12' 2x4 rather than perpendicular to the joists. Is that OK?
12' 2x4 joists on 16" centers is going to make for a springy floor with little loading capacity. For that span you'd want 2x6" joists
16"OC. If you really want to use 2x4 joists, run them the other way and put them 12"OC
Pick up a couple treated 4X6X12 (or 14s even better- the extra length can support a nice step in front) for your skids, cut an angle on the bottom corners so they can actually perform as skids if you move it later. Set them level on 4 concrete pads. Use treated 8' 2x6s for your joists. Cantilever the joists out over the edges of the skids about a foot or so (effective joist span 6'). Use a double rim joist if you want under the load bearing walls. Square up the joist system and hurricane tie the joists to skids. I built a similar shed 10X14, and use the space under the joists between the skids to store utility lumber. Nothing really wrong with the direction your proposed joists run, its just that they run 12 ' unsupported and will be spongy at best.
Right now I can't think of any particular reasons one way or the other, although it might depend exactly how your walls are constructed.
In my own case, and this is partly because of sloping ground, the construction is somewhat different. I first dug out a hole about 15" deep, laid down a couple of inches of concrete, and then built a brickwork square, which finishes a couple of inches above ground level on one side but, because of the sloping ground, is largely exposed on the other.
Air-bricks were let into the exposed side and on the other 6" drain-pipe was used to provide an air passage so allowing under-floor ventilation. Well creosoted 4x4s were then laid on top of the brickwork, on a mortar bed, to form a square and the shed built on top of that.
Three sides were constructed using four 2x2s to form a square with two further intermediate 2x2s vertical. A layer of polythene was laid across before nailing on the "Feather edge" board which forms the side. The fourth side was constructed the same except that the vertical 2x2s were replaced by 4x2 to form the opening for the door.
It was originally built for use as a photographic dark-room so the provision of any windows was felt unnecessary. I still think this was a good idea as it means increased security. The door was also constructed of feather-boards on a 4x2 frame, allowing the use of a five-lever mortice lock.
Brick pillars were then built inside the brick square at appropriate places to carry the ends of the (also well creosoted) floor joists.
Once the sides were erected and the whole fixed together, 2x2 beams were laid across, raised at one end to provide a fall, to carry the boarded, felted roof.
Since then the original inside hardboard skin has been removed and insulation to walls and ceiling added, before replacement.
Note that he is using four 4x4 skids so, as I read it, with those spaced equidistant, the joists will be supported at intermediate points and the maximum required span only 4'
It appears that you have not gotten a permit. For a building that size the cost of the permit would be minimal. You would have a qualified person that you could get all of these questions answered.
Some of the answers you have received would not be to code in many locals. I gather from your question that this shed is one of your first projects. Do yourself a favor and get a permit and build it right.
If the outer 12 foot 2X4s are directly supported on the 4X4X8 sleepers, putting the load bearing wall directly on top of the 4X4 would appear to be the best solution, assuming you are using solid lumber for the floor decking, and that decking extends to the outside of the platform so the sill of the load bearing wall rests on top of the flooring. I would not try that with OSB floor decking. I'd have the sill extend 1/2 inch past the end of the floor (basically center the joist under the sill) to adeqately sheild the ends of the floor deck from the elements - and bring the siding about the same distance below the sill. Just my opinion/observation
I would also strongly suggest 2X6 for the floor joists though - even on 16" centers.
In many areas (mine included) with no permanent foundation and under
100Sq Ft no permit is required or issued and no "code" applies. Put a permanent foundation (concrete slab or sonotube frost foundation included) under it and a 30 sq foot shed requires a permit and has to meet all applicable codes.
Pour a 100 sq foot slab this year, and drop a 50 sq foot shed on it next year, and no permit is required. Bolt (lag) a 100 sq foot shed to that slab, and you better have a permit.
It does not make any difference which way the skids are oriented - at least in regards to the "bearing" walls. Think of a house - there is no change in wall construction or framing between a house with a gable roof or one with a hip roof. The floor platform can take whatever you throw at it...as long as your floor platform is built to standards.
If you're ever going to move the shed, it would be better to have the skids running the long way - it'd be a bit easier to move.
Floor joists should be 2x6 material 16 inches on center.
Beams (your 4x4's) really should be 2x6 material, too - doubled up / sistered together.
If you go to LOWES (or equivalent) and use their design tool to build a deck of the imensions required, you will get a "foundation plan for your shed that will carry the load of a single-story shed with ease.
The metal re-enforcing stuff (forgot the name) is a good place to look for details on deck building as they produce a booklet on it which provides load factors and joist spacing for different size beams and joists. And diagrams.
I used these tools to build a 12 x 16 deck and it's as solid as the house - maybe better!
If you are intent upon placing your"skids" i ground contact, consider laying a few inches of gravel underneath each skid. It will elp with leveling and water run-off.
And if not on gravel that can run off - and I suggest making a tray of cement that holds the gravel - keeping it from just sinking into the ground - but have the tray that holds piles of stone have holes in all corners. e.g. just have plastic pipe act as a form to keep out the cement - then knock them out.
They will drain - they will hold up the stone from just being driven into the ground.
This is a lesson learned on doing driveways. Never pave them with stone when muddy. Only dry and hard - lay down stone.
Mart> >> I'm about to build a 12' x 8' gambrel roof shed.
I plan to sit the skids on a few inches of concrete blocks.
I built an 8x8 of similar design, and pulled it with my 20hp tractor. Now then 8x12 is going to be 50% heavier, so not sure dragging it around is going to be much of an option, but if I had to, then it could be possible.
Planning 6' sidewall studs and a gambrel roof. I tend to sort of play with the layout to optimize the standard building materials.
So it sounds like the 8' skids are fine; I also got that from a reputable contractor I know.
It appears that you have not gotten a permit. For a building that size the cost of the permit would be minimal. You would have a qualified person that you could get all of these questions answered.
Some of the answers you have received would not be to code in many locals. I gather from your question that this shed is one of your first projects. Do yourself a favor and get a permit and build it right.
In many or areas, if it is built on skids, it is portable, and no permit is required, or perhaps even impossible to get on such a building. That is why most sheds are built on skids, even if they are never moved.
I would add to put a hole in a 4x6 skid for a chain to pull the shed, and fasten the joists to the skid with metal connectors, like the hurricane clips that are used to attach roofs to the wall. You would likely pull the skid loose, if you ever moved it without clips. Also get a tiedown kit and keep it from blowing over in a strong wind storm.
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