Search the forums

Loading

Concrete driveway specifications

charlybuse's picture

I am replacing and adding to an existing concrete driveway.  I obtained several estimates from concrete/landscaping contractors.  Upon reviewing them I noted that there is significant variation between them in what items are mentioned and how they are specified.  I then asked around to people I knew who had had driveways done and was given minimum specs that seem to be above what the estimates were suggesting.  I want to request the contractors to resubmit estimates to a consistent set of specifications and am wondering what to require of them.  I want a top quality, long lasting result and don't mind paying appropriately for it but at the same time I don't want to go off the deep end and specify something that is beyond what I reasonably need.


Here is what has been suggested I specify:



  1. 8" to 12" crushed limestone base

  2. 4" steel wire mesh reinforcement

  3. Low chirt, 6 bag mix, fibermesh reinforced concrete, 5" to 6" thick

  4. Broom finish

  5. Saw cut expansion joints

  6. Sealer

Is this a reasonable specification?  Is there anything else I should specify?  Anything else I should ask about or be aware of?  Should I stick with a contractor who only does concrete or is this something one of the landscape contractors are capable of?


One friend who has had several concrete jobs done insists that proper curing is critical to a long lasting surface (even with the sprayed on sealer coat applied).  He recommends laying a soaker hose with a slow trickle going and plastic sheeting over the surface for 7 days followed by another 21 days of continued plastic sheeting coverage without the soaker hose.  Is this the best way to do it?  Any other recommendations?


 

(post #90418, reply #1 of 7)

Find the a local contractor for these folks http://www.patternedconcrete.ca/

or http://www.bowmanite.com

.

Phill Giles

The Unionville Woodwright

Unionville, Ontario

<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /> 

Phill Giles

The Unionville Woodwright

(post #90418, reply #2 of 7)

I just read an article on this subject over at the JLC site.   Unfortunately, you'll have to pay to read it.


http://www.jlconline.com/cgi-bin/jlconline.storefront/3d64d9c800130327271a401e1d2905ce/Product/View/9006rura


They stressed the need to provide proper drainage on both sides of the drive.  They also recommend the use of geotextile fabric between the soil and the gravel.   Other than that, their advice followed yours pretty closely.  They suggest 6" to 8" of 3/4" to 1" aggregate as a base, 6" of concrete, reinforced with 4" wire mesh and #4 rebar across the saw cuts, sawcuts 1.5" deep every 12' (or 1/4 of the depth at a spacing of 3' for every 1" of depth, if you use a depth other than 6"). 

"Listen, strange women lying in ponds distributing swords is no basis for a system of government."

Jon

(post #90418, reply #3 of 7)

Gabe Martel, who answers post here occassionally, wrote an excellent article about concrete flat work for JLC a few years ago. He is the resident expert, so let's hope he jumps in here.

The one thing that should be added to your spec. is "compacted" soil and stone. It won't make any difference how strong a mix you use, or how well it is cured if the stuff it is setting on moves in a few months or years. That is right out of Gabes' article, and based on my own experience over the last 28 years, he is right.

(post #90418, reply #4 of 7)

8 to 12" of crushed limestone seems a little excessive to me, this is usually 4"-6" tamped--are there specuial circumstances that require this (living in a floodplain for example)


5"--6" is also thicker than usual for a driveway slab, here in CA (on flat, theyre usually 4'--5''


I also don't know where you live--concrete mixes should be designed for specific conditions--there are people who do just this, go down and talk to someone at a local batch plant and see what they use.


The curing is especially necessary where weather is more extreme--snow to blazing sun--and also depends on the weather when poured.  Youre mix sounds basically right to me--why did the contractors come up with something different? Perhaps they know something you don't--In CA, contractors are required to guarantee our work for a year, this would include cracks--long ago I had to redo a whole driveway for messing up the exposed agg (don't EVER work it after spraying the retardant!!) With that kind of gurantee, I've turned down jobs that had specs I couldn't live with, I'd rather stay home and go broke than work my #### off and go broke.


More importantthan the mix here is to review references and see past work, talk with past clients--did the guy do a good job and work well with people? these are more important qustions.


in CA we have special ACI and ICBO certed inspectors that inspect the mix, rebar,placement. you might hire one of these where you live


Edited 8/22/2002 9:22:28 AM ET by EXLRRP


Edited 8/22/2002 9:24:07 AM ET by EXLRRP

(post #90418, reply #5 of 7)

Two things that I did not see.

Air entranted (sp?) concrete. That is a must if you are in a freezing climate.

And a requirement for support for the wire mesh so that it is centered in the slab.

Just throwing it in to the form so that it is on the bottom does not do anygood.

. William the Geezer, the sequel to Billy the Kid - Shoe

(post #90418, reply #6 of 7)

If you are replacing an existing driveway make sure the price includes hauling away of the old pavement if thats what you intend them to do..............

(post #90418, reply #7 of 7)

Skip the mesh,and use a rebar mat instead, particularly if you have poor soil or lots of frost. Compacted base , thickness depends on substrate. 6 Bag aka 4000 psi mix, air entrained if in frost climate , as was said. Oh , and 6" slab. Best of luck!


 Brudoggie