How high off gravel base?

Started by Swamphunter, April 21, 2012, 08:31:08 AM

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Swamphunter

My 20x24 cabin will be on 6x6 skids. I am setting it on a gravel pad in an area with adequate drainage. Should the cabin be raised higher than just the 6x6 skids by putting it on concrete block? If so, I was thinking 2 courses of block so I can shimmy under it should I need to. Even though there is no power or water. I forgot to mention, everything is PT flooring....


Redoverfarm

Quote from: Swamphunter on April 21, 2012, 08:31:08 AM
My 20x24 cabin will be on 6x6 skids. I am setting it on a gravel pad in an area with adequate drainage. Should the cabin be raised higher than just the 6x6 skids by putting it on concrete block? If so, I was thinking 2 courses of block so I can shimmy under it should I need to. Even though there is no power or water. I forgot to mention, everything is PT flooring....

Personally skids are OK for a shed or storage building but a living quarters I would have to be higher off the ground. Not that it would make any difference ocupancy wise but it would get the skids off the ground and provide better air circulation to prolong the life of the foundation.  But when you raise it up you should anchor it because the foundation area has decreased and could be like a big sail on the ocean. ;D


alex trent

If the 6x6 are PT and the gravel is well drained, not a whole lot to gain from a couple of blocks.  Where the blocks meet the wood, you still have rot potential.  You may even get more moisture blowing under in heavy wind.

And as mentioned, you now start to have considerations with lift, differential settling with the blocks.

Squirl

If raising it with blocks, the 6x6 skids become girders if there are any spaces between the blocks. 

MountainDon

Swamphunter; not a lot of responses to the question you posed.

My thoughts;
1. that size of building is too big for sitting on skids.

2. as Squirl pointed out raising on blocks gets you into another area; when there are spaces between blocks the skids become beams. The blocks become columns or piers. They don't have a good footing. The load from the building will not be evenly distributed over all the blocks/columns/piers.  It's not a good foundation.

3. Rather than sitting on blocks, waiting for something to happen, I'd leave it sitting on gravel/ground. But then how do you deal with settling. To me it is inevitable that there will be some settling issue down the road. Pretty much impossible, IMO.

Not what you wanted to hear,.....
Just because something has been done and has not failed, doesn't mean it is good design.