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Posted by carolyn on November 3, 2006, 3:55 am
RicodJour wrote:
> Robert Allison wrote:
>> AndyS wrote:
>>
>> > I just got a bid on a 310 long driveway, 14 feet wide.
>> > It is to be 4" thick with rebar 18" OC.
>> > The bid is for $2.65 per sq foot.
>> > Is this a competitive bid ???
>> > The area is North Texas
>> >
>> > Andy in Eureka
>> >
>>
>> That is way cheap. And way too thin. I would go with at
>> least 5" of concrete for a driveway. Sidewalks are 4" thick.
>>
>> Does that include base and prep work? To give you an example,
>> for flatwork like that, the going rate around here is about
>> 5-6.00 a square foot with base and prep. I would be careful
>> about the prep especially. Without it, you are going to be
>> unhappy.
>
> I don't like rebar in such a thin slab, or in driveways at all for that
> matter. A thicker slab and no rebar is better than a thinner slab with
> rebar. As RA opined, the prep work is where corners would be cut and
> what would cause the driveway to fail.
Can you tell us why you don't like rebar in a thin slab? My understanding
is that concrete has great compression strength, but snaps easily when
pulled apart. The weight of a car on the top of a slab pushes down on the
top of the slab, applying compression strength to the top, while the bottom
of the pad is being pulled apart. Enough weight, and the cracks form in
the bottom of the pad and tear through the top. Put the rebar in the lower
half of the slab, and it will hold the bottom together and prevent that
tear through.
I don't know how think it needs to be for what weights, and 5" may be enough
for cars, but what about the 18 wheeler delivery truck, dropping off a new
table saw? (Yeah, my saw and drill press were delivered in an 18 wheeler.
5" and rebar may be over minimum code for a driveway - but the worst that
will happen is that it will be too strong and last much longer than it
otherwise would.
Carolyn
> I'd be nervous with a price that low. You need some additional bids.
Additional bids, and detailed bids, including the subbed. (I think that is
the term.)
Carolyn
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Carolyn Marenger
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