Shed Building question

[fitzhue]

We have a concrete slab in our backyard that was poured by the previous owner to build an over sized 1 car garage. It's about 16x20' with a sloped apron about 4.5x16'. Since we don't exactly have the funds right now to build a garage, I would like to get one of those ready to assemble sheds at Lowe's and I found an 8x12' one that I like.

The instructions say if you're building it on a slab to anchor pressure treated 2x4's to the ground to form the foundation. The problem is I want to put the shed in the corner of the yard on part concrete slab that is sloped (about 2 feet of it as shown). What would be the best thing to use to shim/support that side and would I need to worry about anchoring that side to the concrete? Thanks.

Here are a couple pictures: http://imgur.com/DZyLfuy,fgwhgDZ#0

 

[DrPizza]

I'm not 100% certain, but aren't those kits more expensive than simply purchasing the supplies separately? Especially if you purchase the lumber from a lumberyard. OSB is dirt cheap right now; I think around $8 per sheet last I looked. Steel roofing is only about 70 cents per square foot if you shop around.

How many years do you want the shed to last? I think that I would bring the concrete up level first - drill and put my anchor bolts in first, with the threads at the right finished level, then build a 4 to 6" wide form to fill with concrete to bring it all up level. I don't think I would bring the entire floor up level - just where the walls will be. With the anchors in the original concrete, you won't have to worry too much about the bonding between the new concrete and the old. This would be a good thing if you went with a garage 5 or 10 years from now - you could easily chisel off that concrete and grind off those bolts.

Or, you could install all the 2×4's level with one another, and rip some 2x6's or 2x8's as necessary to fill the gap underneath on the sloped sides. I'd especially consider that if the difference in height were close to a multiple of 2x4 thicknesses.

Or, you could trim down the height of the high side, and also adjust the slanted sides accordingly to match the contour of the slope. Personally, I think this would be the most frustrating - that comes after reframing a few walls with a second layer of wall, where the base and top were of slightly varying slopes from years of settling. Measuring and cutting one 2x4 at a time was annoying (not enough space to build the wall, stand up, and shim.)

I am an amateur though, so I'll defer to someone like Greenman's judgment.

 

[Greenman]

I would anchor the PT to the flat part of the slab, then shim the part over the sloped section with wood shims, then pack it with engineered grout available at Home Depot. Once dry, anchor down the part where the grout is. Wedge anchors would be best, tapcons will do.
The other method would be to rip a 2x4 to make a continuous shim, but that's a bit tougher and probably more effort than is necessary.

 

[DrPizza]

Another point generally in favor of non-kits: many, if not most of the kits are 2x3's spaced 24" on center, not 2x4's 16" on center.

 

[fitzhue]

The kits are more expensive but I just don't have the time right now to build one from scratch. The wife wants me to pay someone to build it so it's done quicker - but I don't feel like paying an extra $1,000 for that luxury. They also have kits that are 2x4 and 16" OC.

Greenman, I'm having trouble visualizing your suggestion. The gap is about 1.75 inches, so just a little less than the thickness of a 2x4. Would I just place 2x4 blocks under the gap and then use shims to take up any additional space, and then pack the whole thing with grout? Thanks.

 

[Greenman]

The kits are more expensive but I just don't have the time right now to build one from scratch. The wife wants me to pay someone to build it so it's done quicker - but I don't feel like paying an extra $1,000 for that luxury. They also have kits that are 2x4 and 16" OC.

Greenman, I'm having trouble visualizing your suggestion. The gap is about 1.75 inches, so just a little less than the thickness of a 2x4. Would I just place 2x4 blocks under the gap and then use shims to take up any additional space, and then pack the whole thing with grout? Thanks.

That's exactly right, but that's a big gap. If you have access to a rotohammer a better method would be to drill 3 or 4 bolts into the concrete pad and use a nut and plate washer to support the bottom plate, then another nut and washer on top of the plate.

Btw, the doc is right, you can build a better shed for less money than buying a kit. Though you do give up convenience.

 

[DrPizza]

That's it? Less than 2"? Somehow, I was thinking it was 4 or 5 inches. what I suggested is too much effort for that little bit of a difference.

Those kits come pre-cut?

 

[twinrider1]

Putting a shed on concrete may increase your property tax.

A 2x4 is actually 1.5x3.5.

Maybe I missed it, would that slop be on the back or the side?

I'd rip pieces to cover that gap, and bevel them if needed. Just be sure to run them perpendicular to the floor joists.

I don't see a need to anchor the shed.

 

[olds]

I can't see the image at work and I am unsure how big a gap you are trying to fill.
I built a shed on an uneven concrete pad. It was skid mounted and I built the skids out of
4X6s with one side ripped down to make up the height difference.

xx...XX

 

[TheGardener]

A garage will likely increase your property value. Sorry you can't afford that. Some how I don't see the shed doing that.