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Home > Archive > Building and Construction > August 2006 > Evaluating bids for concrete driveway
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Evaluating bids for concrete driveway
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| allan230@mailinator.com 2006-08-11, 3:25 am |
| Have obtained 2 bids for an approx 3400 sq ft driveway
Both bids specify 4" of 4000# concrete, finished and sealed, with sawed
control joints. One bid specifies 6x6 6 ga. wire reinforcement, the
other specifies 3/8" rebar 3' on center. Would one be preferable to
the other? Is 4" enough thickness, for a residential driveway? I'm in
Indiana, so winters almost always have a couple of periods where the
lows are below zero.
Existing driveway is gravel, depth unknown, about 5-6 years old.
Getting pretty weedy.
The bids vary a lot, one being $4.60/sq ft the other about $3.10.
Anything else to consider, or ask for clarification on? Neither bid
mentions much about excavation and sub-grade prep, though it was
discussed verbally with both contractors.
Allan
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| go with the welded wire mesh and pick up some #4 bar from lowes or
wherever put some bars where the street transition is and the garage
entry and if you park your truck outside around where the tires are. If
you have a culvert under the driveway put some in there as well. I also
live in Indiana. Expect your property taxes to go up in 2 years as
well. Rebar is cheap and not rocket science to put down. One word of
warning the mesh MUST be pulled up into the concrete, leaving it flat on
the ground is useless
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| Kickstart 2006-08-11, 9:25 am |
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>
> Both bids specify 4" of 4000# concrete,
> Existing driveway is gravel, depth unknown, about 5-6 years old.
> Getting pretty weedy.
>
>
> Anything else to consider, or ask for clarification on? Neither bid
> mentions much about excavation and sub-grade prep, though it was
> discussed verbally with both contractors.
>
> Allan
>
6" works best if your long term and don't want cracks
Wire mesh or fibremesh equal
Rebar on thickened perimeter and @ tie in areas
No decision as to removing the gravel ?
Concrete should be over compacted soil with vapor barrier although driveways
don't necessarily need the vapor barrier
kickstart
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| <allan230@mailinator.com> wrote in message
news:1155264533.526064.60270@h48g2000cwc.googlegroups.com...
> Have obtained 2 bids for an approx 3400 sq ft driveway
>
> Both bids specify 4" of 4000# concrete, finished and sealed, with sawed
> control joints. One bid specifies 6x6 6 ga. wire reinforcement, the
> other specifies 3/8" rebar 3' on center. Would one be preferable to
> the other? Is 4" enough thickness, for a residential driveway? I'm in
> Indiana, so winters almost always have a couple of periods where the
> lows are below zero.
>
> Existing driveway is gravel, depth unknown, about 5-6 years old.
> Getting pretty weedy.
>
> The bids vary a lot, one being $4.60/sq ft the other about $3.10.
>
> Anything else to consider, or ask for clarification on? Neither bid
> mentions much about excavation and sub-grade prep, though it was
> discussed verbally with both contractors.
>
> Allan
>
Thickness is adequate for standard residential automobile traffic. But, not
concrete trucks or heavily laden delivery trucks like one delivering topsoil
to the place for instance.
You should have perimeter beams for both water erosion protection, and when
your car may drift off the perimeter of the driveway.
Be sure the apron at the street is well reinforced with rebar as the pointed
edges seem to want to break off first. Be sure the street apron provides
drainage for the shoulder, not diverting water on your property. If the
street has a curb, be sure the curb is replaced properly.
Don't sign anything unless the party specifies excavation and preparation,
and cleanup afterwards. This should also include topsoil replacement where
the forms were removed.
--
Jonny
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| inspector.terry@gmail.com 2006-08-11, 8:25 pm |
| allan230@mailinator.com wrote:
> Have obtained 2 bids for an approx 3400 sq ft driveway
>
> Both bids specify 4" of 4000# concrete, finished and sealed, with sawed
> control joints. One bid specifies 6x6 6 ga. wire reinforcement, the
> other specifies 3/8" rebar 3' on center. Would one be preferable to
> the other? Is 4" enough thickness, for a residential driveway? I'm in
> Indiana, so winters almost always have a couple of periods where the
> lows are below zero.
>
> Existing driveway is gravel, depth unknown, about 5-6 years old.
> Getting pretty weedy.
>
> The bids vary a lot, one being $4.60/sq ft the other about $3.10.
>
> Anything else to consider, or ask for clarification on? Neither bid
> mentions much about excavation and sub-grade prep, though it was
> discussed verbally with both contractors.
>
> Allan
Allan, The APWA suggests that 4" is not a sufficent depth for vehicle
traffic and that 6" be installed. However, many 4" drives have been in
for years without major problems. If #4 bar is installed it must have
3" of cover between it and the earth. It must also have 1 1/2" minimum
cover over the top. This would be 3 + 1/2 + 1 1/2 or 5" minimum.
Mesh can be used, however it is hard to get it into proper placement
and keep it there. If mesh is used i would suggest that mat and not
roll material be used and that you get chairs to maintain proper
placement.
Bar can then be placed at the perimiter and dowled and epoxied into
existing concrete at locations where the concrete depth can be made to
accomidate.
Terry
Combination Building Inspector
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| Italian 2006-08-12, 9:25 am |
| First of all I would give the contractor that included the rebar extra
consideration. Yes wire is adequate and meets code but if after you
have removed as much concrete as we have in a lifetime you realize that
wire is slightly better than fiber which is completely useless.
You mentioned sealed what are you refering to? A standard finish slab
(not stamped) would not require a sealant..
Also with todays redi mixes I will gaurantee you will get cracks a savy
contractor will know this and place the joints at a proper depth and
orientation to controll these cracks...but unfortinutally even with the
best effort it still cracks where its not supposed to.
4" should be just fine for where you are we allways make the perimiter
a little thicker usually about 3" just for insurance.
Neither bid
> mentions much about excavation and sub-grade prep, though it was
> discussed verbally with both contractors.
Um......this being MORE important than anything else in the job I would
get specific clarification on this. The majority of time (labor cost)
is eaten up in this step, forming and pouring is the easy part. The
condition of the existing drive way must be examined befor proceeding.
Being that it is gravel and has been in use for several years is a plus
you have been essentially compacting it for several years now. On the
other hand areas that collect water must be looked at and fixed. One
final note about rebar VS wire mesh..simple test take a piece of rebar
1 foot long and a piece of wire mesh 1 foot long and see which one you
can bend...
allan230@mailinator.com wrote:
> Have obtained 2 bids for an approx 3400 sq ft driveway
>
> Both bids specify 4" of 4000# concrete, finished and sealed, with sawed
> control joints. One bid specifies 6x6 6 ga. wire reinforcement, the
> other specifies 3/8" rebar 3' on center. Would one be preferable to
> the other? Is 4" enough thickness, for a residential driveway? I'm in
> Indiana, so winters almost always have a couple of periods where the
> lows are below zero.
>
> Existing driveway is gravel, depth unknown, about 5-6 years old.
> Getting pretty weedy.
>
> The bids vary a lot, one being $4.60/sq ft the other about $3.10.
>
> Anything else to consider, or ask for clarification on? Neither bid
> mentions much about excavation and sub-grade prep, though it was
> discussed verbally with both contractors.
>
> Allan
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| allan230@mailinator.com 2006-08-13, 1:25 pm |
|
Italian wrote:
> You mentioned sealed what are you refering to? A standard finish slab
> (not stamped) would not require a sealant..
"Broom" finish was specified, followed up by "commercial grade sealant"
> 4" should be just fine for where you are we allways make the perimiter
> a little thicker usually about 3" just for insurance.
Meaning, 7" at the perimeter?
Allan
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| allan230@mailinator.com 2006-08-13, 1:25 pm |
| MAny thanks for all the info. I am going to get one more bid before I
decide anything.
Allan
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| Concrete Is Green 2006-08-14, 9:25 am |
| Allan,
4 inches is standard thickness for residential driveways in Indiana.
As others have stated, it is rare that wire mesh, either roll or mat,
is located properly in the middle of the slab with sufficient cover to
avoid corrosion. I would suggest fibers instead of mesh. The fibers
make the concrete mix more homogenous, and reduce cracking during the
placement and curing of the concrete, so that there are fewer cracks in
the final product. Make sure that the contractor is placing joints no
more than 10 foot apart, and as square as possible, and is placing
expansion material between the driveway and any other structures or
concrete.
Curing is the most neglected and one of the most important steps in
installing a quality concrete driveway. A driveway installed with 4000
psi concrete mix, properly finished but not cured properly, will have a
top surface of 2500 psi concrete that is very porous, and it will be
more likely to have surface defects with freezing and thawing, and
especially with de-icing chemicals.
The Indiana Ready Mixed Concrete Association, (where I work), is a
Non-Profit organization promoting quality ready mixed concrete in
Indiana. We have residential concrete guidelines available for
homebuilders, contractors, and homeowners. You can go to www.irmca.com
to get in touch with us.
Brian
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