Pressure treated or not?

Old 12-19-17, 04:08 PM
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Pressure treated or not?

Designing a storage shed/barn. It is 16' x 20' and will set on a gravel foundation with five 20' long 4x4 PT skids. Do I/Should I use PT wood for the floor joist that sit on the skids? Is that over kill?

Old 12-19-17, 04:17 PM
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Yes, due to its close proximity to the ground, both the joists and decking should be treated.
Old 12-20-17, 01:58 AM
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PT for anything in contact with ground so technically not needed but peace of mind might be worth a few extra $.
Old 12-20-17, 02:40 AM
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I'd use PT for 2 reasons; being close to the ground if moisture collects under the shed the lack of air movement will make it dry slow ... although the gravel helps. and you never know when nature/rodents might change the elevation enough to cause that lumber to come in contact with the earth.
Old 12-20-17, 03:38 AM
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Make sure the PT is for ground contact. There is a difference.
Old 12-20-17, 05:46 AM
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Your shed might start out 3.5" above the gravel but will eventually sink and eliminate most of that gap. In addition to the gravel (compacted) and the skids I would position several 4" solid blocks under each skid. The added height will help with the ventilation underneath and ensure your shed doesn't eventually sit flat on the ground. I see you are in CAL which may be warm or both so if in a frosty zone it gets worse.

Also, the extra elevation will help protect the siding from the rain coming off of the roof.


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