Hi all, was hoping for some input. Sort of a noob to shed building and trying to put up an 8x12 on skids. I'm in the midwest and best I can tell (no clear cut answer beating google to death) the frost line's around 20" or less.
The plan is to create a gravel base around 6" deep (maybe an inch more or less since the ground is sloped) using 1" minus - what the guy I called for gravel said they use for crusher run/road base around here. My soil consists of little top soil with a lot of clay (unfortunately). Is this the best plan of action without pouring a solid slab or using sonotubes? Is 6" (planning to compact with a compactor) enough with a timber retaining frame and landscape cloth underneath to prevent the gravel from mixing into the clay?
Planning to use 4 4x4 pressure treated skids - would there be an issue placing them on 8x16x4" thick concrete blocks set into the gravel? Not sure how far apart to space them running the length of the 12' 4x4's - 16" apart (basically place a block, skip one, place one) or up to maybe 2 block lengths in between (32")? Some have said this will cause pressure points which cause the shed to sink, but I'm not sure if this is only when blocks alone are set directly on the ground. I know many people like the 4x6 or 6x6 skids, but I don't have access to 4x6 and 6x6x12 pressure treated are close to $40 in my area - vs 4x4x12's pressure treated which run under $15 each. 4x4's should work well enough shouldn't they?
Also I know there should be something between the 4x4 skids and the concrete blocks to prevent moisture wicking. Some just cut a piece of shingle to put underneath as a barrier, but I'm planning on a sheet metal roof and seems like a waste to buy a pack of shingles just for this. Would tar paper work? Maybe even folded over or something to double up the thickness.
Sorry for all the questions, last time I built anything like this I was in the southwest where it was nice and arid, no mushy clay to fight with and much better drainage. Dealing with humidity and clay soil definitely adds to the adventure. I just don't want to invest time and money into this only to have a pile of junk in a year or two half sunk into the ground. Thanks for any ideas or advice.
The plan is to create a gravel base around 6" deep (maybe an inch more or less since the ground is sloped) using 1" minus - what the guy I called for gravel said they use for crusher run/road base around here. My soil consists of little top soil with a lot of clay (unfortunately). Is this the best plan of action without pouring a solid slab or using sonotubes? Is 6" (planning to compact with a compactor) enough with a timber retaining frame and landscape cloth underneath to prevent the gravel from mixing into the clay?
Planning to use 4 4x4 pressure treated skids - would there be an issue placing them on 8x16x4" thick concrete blocks set into the gravel? Not sure how far apart to space them running the length of the 12' 4x4's - 16" apart (basically place a block, skip one, place one) or up to maybe 2 block lengths in between (32")? Some have said this will cause pressure points which cause the shed to sink, but I'm not sure if this is only when blocks alone are set directly on the ground. I know many people like the 4x6 or 6x6 skids, but I don't have access to 4x6 and 6x6x12 pressure treated are close to $40 in my area - vs 4x4x12's pressure treated which run under $15 each. 4x4's should work well enough shouldn't they?
Also I know there should be something between the 4x4 skids and the concrete blocks to prevent moisture wicking. Some just cut a piece of shingle to put underneath as a barrier, but I'm planning on a sheet metal roof and seems like a waste to buy a pack of shingles just for this. Would tar paper work? Maybe even folded over or something to double up the thickness.
Sorry for all the questions, last time I built anything like this I was in the southwest where it was nice and arid, no mushy clay to fight with and much better drainage. Dealing with humidity and clay soil definitely adds to the adventure. I just don't want to invest time and money into this only to have a pile of junk in a year or two half sunk into the ground. Thanks for any ideas or advice.