By James Allen
Carol of St. Clair Shores MI:
We are considering having a replacement driveway poured. I have received three estimates but I have questions before the work is done.
(1) One estimate includes cement, mesh wire in the driveway, steel rods in the garage, expansion paper, crushed concrete for a solid base.
(2) Second estimate includes cement, no mesh wire in the driveway, no steel rods in the garage, asphalt expansion instead of expansion, crush concrete for a solid base. They did not use expansion paper because of deterioation and did not feel it necessary to use steel rods nor wire mess.
Question: what is the best decision for residential driveways? Why? Please let me know very soon. It will influence my decision.
If youre going to drive on it, then, IMHO, you need steel rod. Thats reinforcing rods. For a driveway, #3 (3/8" diameter) or #4 (" diameter). They say you can use 16-gauge wire mesh to reinforce the concrete. But I think that the mesh doesnt much reinforce the slab against cracking, it only helps to keep the pieces from moving around too much, after it's cracked. Steel rod reinforces the concrete. You might be able to get away with mesh, or even nothing, if the concrete is thick enough and/or if it's on a really good substrate. But if you put enough steel in it, it wont matter too much what is or isn't under it. Considering costs, you want to achieve a balance between substrate prep,
reinforcement, and thickness. Many contractors and builders do driveways on the cheap, but I never did like the sight of cracked slabs.
I havent done concrete in a good while, but I did do a few driveways. The substrate is number one. I dont know whats being used for subbase these days, but I always used a type of graded bluestone called A21. Even crusher-run is okay for driveways. As thick as you can afford it, say, at least 4" compacted, over compacted the earth. (Many builders just pour over dirt).
Inside you may want a vapor barrier over the compacted gravel. Then I set up slab bar bolsters for 5-1/2" concrete, and wired my steel rebar to that, about 12" apart. Then I wired down another layer of rebar at right angles, again, at about 12". The expansion joints are usually " thick asphalt impregnated paper, but can be anything that resists rot and insects. Thats the set-up. The type of concrete used is also very important. Make sure the contractor isnt using a weak mix. Each concrete company has what they call a standard mix. Call the company providing the concrete to see what they offer, and ask whats best for driveways in you! r area. Be sure its in the contract.
Another possible area to be addressed is tying the slabs together at the expansion joints. Also, sometimes we would rip a half inch off the expansion joint material, then tack it back on with nails. After the cure, we could easily pull up the half-inch strip for a ready sealant reservoir. I understand that you can buy ready made expansion material already ripped (or so Ive seen used around swimming pools).
Some would say I overbuild. But I can drive down the road and see concrete jobs I did 20 years ago that look almost new. Thats a lot to digest, I know. There are plenty of books about concrete construction at your library. Also, your local municipal building department may have some free reading materials available. Give them a call.
Once you have the information, then you can decide how far you want to go, and what you can live with.
PV of Tracy CA:
I have the nastiest rust stain (from the previous owner!) on my driveway. I've tried CLR, but to no avail - I think it's deep in the cement. Any other products you can reccomend??
Try this: first, wire brush the stain heavily and thoroughly. If you have a grinder with a brush cup, all the better. This will help open the pores of the concrete. Then try a strong anti-grease cleaner. Pour some on the stain, work it with a stiff bristle brush, pour on some more, brush again, and then rinse. Let the sun dry it out. Still looks bad? The next morning, before it gets hot, apply some full strength bleach to the stain, then let the sun work on it.
Basically, youre abrading the stain away, and using the degreaser and bleach to lighten some, or all, of whats left. I believe its impossible to remove all of a staining agent that has penetrated deep into the pores of the concrete. But, you can sure lighten it up.