DIY Message Boards
shed on oversized concrete

This topic can be found at:
http://boards.diynetwork.com/eve/forums/a/tpc/f/9321916776/m/7463999377

Sep 22, 2013, 11:31 AM
baseballbuzz
shed on oversized concrete
hello everyone.
I need some advice for the shed I am about to build.
I have a big area, about 50' x 50', of concrete for which I am going to put a 10x12 shed on. I am going to stucco it when finished to match my house here in San Diego.
I am concerned with what to set it on. I am leaning towards 4x4 pt skids but want to have the skids all the way around the shed to prevent any animals from getting underneath. I then want to either stucco the pt skids or paint them. I am worried about moisture. and I was thinking of anchoring it to the concrete.
thanks in advance.
Sep 22, 2013, 11:54 AM
redoverfarm
I would tapcon/wedge bolt 2X PT material at the location where the skids would rest upon and across the ends. Once the skids were slid upon the You may need to place a piece of 2X material to the bottom of the floor joist to anchor the end panels to the shed. Use Simpson or metal tie stap to connect the anchored plate to the skid.

OK we got it anchored now to animal proof. Your skids will be set under the shed (not on the outside edge)so you will have to enclose the ends and on top of the skids where the floor joist bay is located. Generally the floor joist are perpendicular to the skids. This can be done with hardware cloth nailed to the joist sides, floor bottom and skids. Depending on how far the skids are from the sides you may be able to sheet from the skid to the outside wall(underneath ) to enclose. I would use PT ply on the front and back covering the skid ends. In doing so you should cut and install a Crawlspace vent in each end to allow the area between the skids to be ventilated so that the floor and joist will not rot.

It is going to be extremely difficult to stucco the area under the shed and I would opt to paint a corresponding color as the stucco.

This message has been edited. Last edited by: redoverfarm,
Sep 22, 2013, 12:03 PM
baseballbuzz
thanks for the reply. I will tapcon the skids in place and the floor joists will be across the skids. if I do pt plywood around the edge with vents that sounds like the air flow underneath will keep the moisture out. I am a little concerned with the pt plywood going down the sides to the concrete. the water will be running towards it a little but will not puddle up.
Sep 22, 2013, 12:29 PM
redoverfarm
If this is a delivered shed then there is no way (easily) to anchor the skids to the concrete. You would anchor the plate to the conrete and then strap tie or plate the skid to the floor plate.

Your floor joist bottom will be in essence 5" from the conrete. The regular crawlspace vents may be more demensional than you have room. Maybe a rectangular soffit vent would be better suited ( smaller).

This message has been edited. Last edited by: redoverfarm,
Sep 22, 2013, 12:43 PM
baseballbuzz
I am building the shed and I am ready to go except for what to set it on. I am just concerned with moisture and blocking access to underneath.
Sep 22, 2013, 02:09 PM
redoverfarm
I believe if it were mine I would use 6X6 PT instead of 4X4. That would give more room for air. In addition I would use hardware cloth ( Rabbit wire) to block out the critters. You could use that as well for the ends and cover with a lattice material painted to match. The plate could be 2X6PT to match the width of your skids. Try to get "ground contact" 2X material. Most sold are not that.
Sep 22, 2013, 02:13 PM
Jaybee
Will this shed have a floor?

If not, then you could pour a 2" to 4" slab that is sized to the shed. This will give you a good, solid floor that you can also anchor the shed to. It will also keep the floor level up above rainwater on the slab. Down-side is that it will have to remain in that one place. An alternate would be to use pavers to make a raised floor. You will need to strap between the shed and the existing concrete slab to anchor.

If there will be a floor on joists them just build a perimeter of 4x8x16 solid block. You could mortar in place or just dry-stack. Here too, you would want to strap to the concrete for tie-downs.


Jaybee
Sep 22, 2013, 07:14 PM
baseballbuzz
I will have a floor. using 6x6 skids is a thought. I would prefer a concrete pad that is 10x12 on top of the existing concrete but am worried about how it would adhere to it.
Sep 22, 2013, 07:37 PM
redoverfarm
If this is permanent then why not build it convientional on the existing slab. You can use a plate (anchored) as mentioned before and build on top of that with 2X6 or 2X8 rim joist. The later being the best size given the demensions of your building(10') Use the same demensional lumber(PT) for your floor joist and use PT ply. Then you can use white wood after that. Fasten your rim joist to the plate with straps or plate connectors. Just don't run your sheeting all the way to the concrete so it does not wick water.
Sep 23, 2013, 03:35 PM
Frodo
in my humble opinion,,,rendoverfarm's suggestion makes the most sence, money wise...thats how i'd do it