Construction experts...need some suggestions

[kingsransomracing]

who is into construction? I have a few questions about building on a concrete slab.
I am thinking of building a small shed / workshop and just have a few questions. The shed will be 12'x10' (120sq.ft max without permit) It will be wood frame construction.
I don't want water getting into the shed so attaching the 2x4 to the patio slab with .22cal or redheads is probably out of the question. Anyway to seal off so the shed doesn't get water?
Other thought was building a 4.5" x 4.5" concrete base for the walls to mount to in order to keep the walls off of the patio. but then I understand that new concrete doesn't seal or stick well to old concrete slab. so I am sort of lost there..
Any suggestions?

[Mandelon]

When you pour the slab make sure it is up off the grade by several (llike 6) inches. Use treated lumber and put j bolts into the slab. Then you can use them to hold down the bottom plate. Use Jiffy seal under the lumber and wrap it up under the building wrap. Make sure the weep screed is below the plate line when you put the siding on.

[atomickitn]

or ! you could just form a 8" curb around the perimiter (sp) then pour concrete inside of that with dowels from the curb and a rebar mat then just bolt down your bottom plates .........wala! :cool:

[sigepmock]

Is the slab new or existing? If it's existing drill and expoxy some re-bar or bolts into the existing slab, then pour a small 4" curb around the base for the building. The rebar/bolts will help the curb "stick" to the existing slab.
I also like to roughen up the surface of the concrete I'm pouring on top of and use a good concrete "glue" to promote the new sticking to the old.
Chris

[Mandelon]

You are building this on an existing patio slab.......I read it a little closer.
I would use a row of concrete block or form and pour a short stem wall. Scarify the slab first and dowel in some short rebar sticks every 24" or so. To bond them better, roll on a concrete glue prior to pouring. Oil up your form boards so they will release easier. You can hold forms in place with stakes nailed across the tops. If you screw the forms together its less stress on the new concrete if you dissassemble them than if you beat them loose with a hammer.
You can add a few J bolts into the stem wall to hold down the bottom plate. I'd still recommend the Jiffy Seal and wrapping it up under the building paper. Keeps the bugs out much better than not doing it.

[mike37]

we need pics of the slab you are placing the shed on

[NashvilleBound]

Pictures would be very helpfull.....
If you are adding onto a slab with a curb (small stem walls) remember that the cold joint (where old meets new concrete) will NOT be waterproof.
MAKE SURE your above your soils grade and like previously stated install your drip screed (stucco or siding?) below the cold joint. You can drill into your old slab and epoxy "all thread" into it making sure it will be sticking 2 1/2 inches ABOVE the top of your new perimeter concrete walls. This will allow you to bolt your treated wood plate down and keep everything in place.

[kingsransomracing]

ok...I will have to take picture and then put them up for you to look at them. I will have to wait until tomorrow though, since it is already dark outside.
remember that the cold joint (where old meets new concrete) will NOT be waterproof.
This is the area that I was trying to figure out how to waterproof....what can I do in this situation?

[phebus]

Why not just build a stem wall out of block on the existing slab, and run floor joists off of it, and the run the weep screed down over the stem wall.
Just like a new construction raised foundation.

[YeLLowBoaT]

Before you deside to bolt that puppy down make sure you check your local codes... most say somthing about it being "movable" some countys let you bolt it down some don't...

[NashvilleBound]

ok...I will have to take picture and then put them up for you to look at them. I will have to wait until tomorrow though, since it is already dark outside.
This is the area that I was trying to figure out how to waterproof....what can I do in this situation?
If its at all questionable you can get asphalt emulsion (roofing department) and waterproof it with that before framing. But if it is below grade it will eventually leak.....I promise you. There are more expensive waterproofing products but at that point your just better off pouring a new slab on top of the old one and pouring your curbs monolithically with the new pour.

[kingsransomracing]

This is the code:
A building permit is not required for one story, detached accessory structures used as tool or storage sheds, play houses and buildings of similar use provided the floor area, which do not exceed 120 square feet.
Garages, garage conversions, room additions, carports, patio covers, accessory structures and similar improvements which are attached to your home or which exceed the allowable area, require the issuance of a building permit.
Plans for such improvements must be submitted for approval to the Building and Safety Division prior to the issuance of a permit. Permits for smaller projects, which are less complicated, may be approved over the counter provided adequate information is shown on the plans.
It says nothing about attaching it (except to the house)
and here are the pictures:
http://img417.imageshack.us/img417/5264/dsc00730gs0.jpg (http://imageshack.us)
http://img244.imageshack.us/img244/714/dsc00731qv8.jpg (http://imageshack.us)

[NashvilleBound]

Are you going to attach it? If so i reccommend a building permit for the resale of your home someday. How much could it possibly be? Water does not look like a problem the way its pitched to the side....will the door to this shed be on your side yard? If so you should be ok. If not it looks like your going to need to pour a new slab(you will be holding water). No need for stem walls as you'll be outta grade. Just make sure you wrap and frame it right. If you need anything else just let me know.....looks like an easy project. Good luck.
One more thing........ If you do pour a new slab on top of the old one use long fiber in your concrete and 10 10 10 wiremesh. It will be worth the small amount of costs so it holds up instead of crumbling away.

[OCMerrill]

Pretty tough to place a sill plate down on an existing patio like that and make it water tight. If you look at the patio it slopes down to the right of the picture so your new shed will be in the drainage path.
Slab on top of existing or at the very least laminating a 6" high "curb" to build in will be your best bet. Either way scarify the surface first, concrete glue, roto in bolts first just like others have said. When you get done you will have to apply Dry-Loc or water proof the inside if you use the curb idea. It will last for a while but will eventually seep water.
New slab is your best bet.

[Schiada76]

Fire your electrician! :D

[kingsransomracing]

Fire your electrician! :D
haha...that line was from the spa that used to be there. I disconnected it from the spa and am going to use it for the shed (220V)
Are you going to attach it?
I don't plan on attaching it to the house...just to the concrete slab.
will the door to this shed be on your side yard?
The door will be on the side where the other door (left side of the second picture)
The area where I plan on putting this is under a patio cover, so water does not get underthere except for the lower right corner of the second picture (about 1.5feet) if it is a heavy rain like we had a few years ago.
BTW...what about those wood pieces in the slab...should I leave those in or concrete over top of them...and if I take them out, what is the best way to do that?

[sigepmock]

Go down to Home Depot and buy one of their plastic sheds with a floor, it will save you time and money in the long run. The plastic floor won't rot and the raised floor will keep the contents dry. :crossx:

[kingsransomracing]

If I do the curb style.. Looks like I am going to need about 6 cubic feet of concrete (or cement...what would be better? ) That is 12 90lb bags. anyway have a small cement mixer and would like to help out :) free beer :)

[Mandelon]

Cement is an ingredient of concrete, just like flour is to a cookie. So use a concrete mix. I like the plastic shed idea, with a floor...or call Tuff Shed, they deliver and assemble.
Also keep it a foot away from the house. Don't want to block moisture in against the stucco.

[kingsransomracing]

My only concern with the plastic shed is that I would like to install a mill one day and since they way in upwards of 2000lbs, I don't think the plastic floor will handle it :rollside:

[sigepmock]

OK get the plastic/pre-fabbed shed, use your existing concrete patio as the floor. Then just use a good all weather silicone sealant around the bottom between the walls and concrete floor. You may need to touch it up every year or so but it would be a lot easier than building a permant type shed.
I manufacture steel building parts and those pre-fab shed guys have it down to a science. I can't touch what they are producing pricewise or ease of assembly.
Get a door with a threshold, and then just seal the whole shed to concrete floor and be done with it. That's how I'd do it anyway.
Chris

[spectratoad]

A metal flashing may also help with the water intrusion problem and lots of caulk under the mudsill before you attach it to the concrete if you go that way.

[Bradman]

I don't know if this would work for your project, but we built my son's clubhouse up off the ground.
http://i86.photobucket.com/albums/k81/msbladua/DSC00215.jpg http://i86.photobucket.com/albums/k81/msbladua/DSC00216.jpg