concrete slab for carport

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Old 06-15-06, 10:06 PM
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Question concrete slab for carport

How thick should the slab be? We are in the desert so don't have to worry to much about the ground freezing up, it gets cold, but not that cold or for very long.

Do I have to reinforce it with wire or rebar? I have heard they have cement that has fiberglass in it that works well for this type of project.

Do I need to pour a footer? What about where the corner posts are going to set?

How do figure how much cement to order?

Just doing figuring and seeing if I want to tackle this job. Any advice would be appreciated.
 
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Old 06-16-06, 05:41 AM
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Wink

The size of the slab and weight of the vehicle(s) might be useful info when the pro's come along with an answer, Devil Dog. Given your location, you're not a tanker by any chance are you? You would need a stronger slab if you drove your "work vehicle" home than if you were parking a couple of Geo Metros.
 
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Old 06-16-06, 08:41 AM
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Not a tanker....retired radar/computer technician. I will assume, you don't drive a tow truck either?!?

The slab will be approximately 16 X 20, at the most. It is on rental property, so will have a variety of vehicles, but just normal POV's (Privately Owned Vehicle).

Hope that helps. I am still in the planning phase, so trying to get all the information I may need, to make a good decision on this.
 
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Old 06-17-06, 03:39 AM
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1: Mak sure the soil has good weight bearing qualities.....i.e. free of debris and well compacted.

2: Form with a 2 X 8 and keep the slab thickened around the perimeter with 4mil viquine beneath and at least one course of 1/2 " re-rod before tapering the rest of the thickness o 4".

3:Fibre reinforcing can't compare to reinfoorcing entire floor with 6 X 6 welded steel mesh in addition to the 1/2"rerod perimeter.

4: have some experienced help from your fellow marines when the truck arrives............good luck and "Semper
Fi" to you also.

bs5
 
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Old 06-17-06, 03:46 AM
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5. figure 80 square feet o the yard of concrete @ 4" thickness and 40 square ft @ 8" of thickness.
 
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Old 06-17-06, 05:37 AM
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Talking That's "Marines" with a capital "M", bull.

Retired aircraft maintenance chief (fixed wing); now flying a tow truck.

6. When you get to paragraph three of your operations order ("execution" for you civilians), cover the finished pour with a plastic sheet to slow down the curing, which in your neighborhood would happen PRETTY fast in the hot dry climate.
 
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Old 06-19-06, 04:16 PM
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carport slab

Absolute minimum thickness should be 4" thick...and go and extra 2" deep around the edges for about 10" in...Concretes always weakest around the edges..... It's a good idea to run a perimeter of 1/2 inch rebar around the edge.. The fiber-mesh additive, which is added at the plant will probably run about 8 bucks a yard more which is nothing compared to the added strength....The 6x6 mesh is a good idea but it may be somewhat of a pain to wheelbarrow and pour the slab since it HAS to be elevated off the ground at least 2 " Any steel lying on the ground is useless...It has to be in the concrete....If you have a really well compacted area, you can skip the 6 x 6 mesh, But only if you go with the fiber-mesh additive.(Even still, not recommended) .As for your measure.....Take your width x length (in feet) and average out the depth...multiply all three....divide by 27...That'll give you the cubic yards...It's best to tack on 1/2 a yard for the pump and 1/4 yard for spillage....The extra $100 bucks will be less than a stand-by charge. Use good thick poly(Plastic) for the vapor barrier, and you can also have a retardent added to slow the curing process.. (I'm in Canada, and the measures here are in metric, and the price are according to that, a cubic metre at 25 mpa is $150.00, and $13 per metre for the fiber mesh additive. So given the metric/imperial conversion..and the value of the canadian dollar..lol...It shoud be pretty cheap..)
 
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Old 06-19-06, 07:11 PM
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concrete slab for carport

Do not forget to use control joints. Sawed (the next day) are preferred for your type of application. After a couple of weeks, clean the saw cut out and caulk. Tooled joints will work IF you make them deep enough. You have some wide temperature swings in the high desert, so cracking is more of a possibility than near the coast.

You will need more than one 1/2" bar around the perimeter for a carport. The concrete at the edge is not weaker unless you have a poor contractor that doesn't know how to place concrete.

Fiber mesh will minimize the shrinkage cracks, but I would use steel wire mesh (6x6) and consider the fiber mesh as option. This is especially true for your climate, where you will have rapid curing and a tendancy for the concrete to dry out from both above and below, which will increase the shrinkage.

Keep the slab moist as long as possible to avoid having it curl (edges raise) due to the climate.

Dick
 
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Old 06-19-06, 07:21 PM
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1/2" rebar not enough?

considering it's a slab with fiber mesh concrete, what would the added gain of rebar thicker than 1/2" be? Or would you go 2 rows on the perimeter? And considering he's not going with some poor contractor that doesn't know how to place concrete...Wasn't that just good friendly advice Dick?
 
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Old 06-19-06, 07:47 PM
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concrete slab for carport

I was suggesting more than just one 1/2" bar while he is at it. The slab may start out with a carport with 6 or 8 posts, but often these things tend to change function (full garage or addition?).

Since this is in California, there might be some minimum requirements that I have not considered. You can get some nasty winds around there and there is always the seismic situation (only a few miles from some nasty, active faults).

Dick
 
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Old 06-19-06, 07:54 PM
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true true

Well then given those conditions...If the slab was deepened, to say 8"...a 5/8 rebar grid on 1 foot centers...Throw in the fiber mesh for added measure....It'd pretty much be a bullet-proof pad for any garage kept vehicle, or addition..Wouldn't you say?
 
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