Author Topic: 10x20 shed in MD  (Read 273 times)

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Offline LatinForLiar

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10x20 shed in MD
« on: September 07, 2017, 08:53:58 PM »
Starting to construct a 10x20 shed on skids in Southern Maryland. Skids will be 2 20' treated 6x6s. 8' walls with a loft over half of the space. 12:12 roof.

So far I've just been working on prepping the ground for the skids. I dug trenches to remove some of the topsoil and clay. I filled it with bank run and compacted the bank run with a jumping jack until it was about 3-4" below grade, then filled it with marble chips and compacted that.

The site is fairly level. It loses about 8" of elevation along the 20' length. I will use solid concrete block to lift up the low side of the skids.

Any thoughts or suggestions are appreciated.







Offline ChugiakTinkerer

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Re: 10x20 shed in MD
« Reply #1 on: September 08, 2017, 10:55:59 AM »
Depending on your intentions for the shed your footing prep could be overkill.  Were it me, I'd try to level out the marble chips and set the skids directly on it.  If drainage is adequate then your PT skids will be fine resting on the gravel.  If you want to put down concrete block, I'd put several in under each skid to help distribute the load.  As it is you can probably forego the blocks altogether, unless you have concerns about lots of standing water.

Edit to add: A little info on where it's located would be a big help.
My cabin build thread: Alaskan remote 16x28 1.5 story

Offline LatinForLiar

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Re: 10x20 shed in MD
« Reply #2 on: September 08, 2017, 01:04:05 PM »
Location is southern Maryland. Off the grid with only marginal vehicle access (To bring the skids in I am going to have to unload about 1/3 mile away and use a logging arch to get them the rest of the way).  Densely wooded all around. Structure will provide storage and shelter and hopefully be heated with a wood stove.

The skids will be resting on the gravel at the high end. The cement blocks are just to create a level foundation at the low end. I will use several stacks of increasing height in order to distribute the weight across as much of the foundation as possible (the soil is primarily clay).

A couple questions: do people think rebar driven through the skids is necessary? Supposedly it anchors the structure to the ground (though it also eliminates any ability to move the structure later).

Would you use PT plywood as subfloor? I will be using foam board insulation between the joists, which should act as a vapor barrier. I asked this in the general forum as well. Not sure which is the better place to post specific questions.

Offline NathanS

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Re: 10x20 shed in MD
« Reply #3 on: September 09, 2017, 06:07:14 AM »
The rebar won't do anything.

Pressure treated subfloor is also overkill in my opinion, once you have your water barrier and siding it shouldn't get wet. It is definitely wise to use pressure treated rim joists, the interior joists could safely be non treated too to save a little money there. (As long as there is no ground contact)

Plywood ratings are standardized by the APA. There are different exposure categories. Those are the stamps you want to look for at stores. Stores also like to use their own self made categories that are not standardized and just confuse the issue.

In my opinion spend the slightly more money on advantech. That stuff is awesome. Note that sizes are a bit under 4x8 when you are planning you layout.

One thing with the foam underneath is that ants will tunnel into it. You may want to put a screen underneath the joists.

Offline GaryT

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Re: 10x20 shed in MD
« Reply #4 on: September 09, 2017, 11:26:39 AM »
"Pressure treated subfloor is also overkill in my opinion, once you have your water barrier and siding it shouldn't get wet. It is definitely wise to use pressure treated rim joists, the interior joists could safely be non treated too to save a little money there. (As long as there is no ground contact)"

With respect, I am going to disagree with the above...unless the OP puts a VERY good vapor barrier down over the soil, extending a ways out beyond the rims.  I've been in WAY too many dirt floor crawl spaces - even those with some sort of air circulation - where all the joists are severely damaged/rotted via moisture.  Were it I in this situation, I would use all PT joists and subfloor.  Which is exactly what I did in my own back yard (12X16 over gravel bed) 15 years ago, and it's still solid as a rock.

Gary