Your local municipal zoning and engineering departments should be able to answer a few of your questions. They certainly can comment on zoning specs. They may also offer advice on whether you should "over-engineer" some of the specs for your driveway.
Around here, it is very typical for the contractor to skim off the old asphalt, topdress new aggregate in a few spots, recompact the aggregrate, and lay down the new asphalt.
Often the original base wasn't up to spec and the inspectors sometimes do a rather poor job of inspecting the crushed stone before the new asphalt is applied. There seems to be an attitude which assumes that "specs for the old base and the new base haven't changed, we inspected it originally, so we don't need to exert much effort inspecting the base now." Whenever possible, I like to examine any new driveway installation in our neighborhood, and I have observed many which had as little as 1" of gravel in some portions of the base.
Price? You've got to get some folks out for estimates. The cost is going to vary by local market. You may be able to find some general guidelines on the Internet. There are free construction cost estimators available online.
Advice? Get this work done during the hottest part of the summer. You want that new asphalt to stay hot during delivery, when being dumped, and during the entire rolling process. The hotter the mix at the end of the job, the better the driveway you will wind up with.
If you are skeptical, then try an experiment working with some repair material (plaster, Bondo, fiberglass resin, etc.) which starts off "plastic" and eventually sets up. Apply some to a work surface, wait until it is nearly set up, and then continue working (eg: smoothing) the material while it is finally setting up. You will notice a very poor result in which there are many small, localized areas of well bonded material. But those areas are bonded to one another very poorly and the overall intergrity of the work is severely compromised. The same thing happens with asphalt which is allowed to cool too much while it is still being worked. The driveway may look good, but it will have a much shorter life.
More advice: Try to be around when the work is being performed. You want to examine the bed of crushed stone and the compaction. You'll want to confirm the thickness of the aggregate bed at multiple spots prior to final compaction. You are doing that prior to compaction so that you aren't disturbing the final gravel bed.
It is also helpful to watch the asphalt being applied and rolled. I would seriously consider using a non-contact, laser-aimed thermometer to monitor the surface temp of the asphalt as it is being applied and rolled.
Observing other driveways being replaced gives you a lot of input, and certainly you'll want to get references. It is obviously wise to walk through the neighborhood and look at driveways which were replaced 5-10 years ago, check out their condition now, and get the names of the contractors.
Final advice: When getting estimates, check on the extra cost of having an additional 2" of asphalt applied. Of course, this may not always be practical if you are reusing the current gravel base. But, in my opinion, it is a worthwhile option to consider in northern climates, which are particularly rough on driveways.
Good luck, Gideon
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Robert11 wrote
I posted this some time ago, but received only one reply with a suggested Link, which doesn't work.
Thought I'd try again, as really hoping to get some info on. It's such a big expense. Thanks.
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Hello,
Have a home driveway that has to be repaved.
It's been so many years since it was last, I really don't remember any of the details.
I believe a bed of crushed stone was put down first.
Questions:
a. Assuming there is a bed of crushed stones there now, do I want the contractor to remove all this old stone, and put down a new stone bed before putting down the new asphalt ? Why ?
Or, can he just remove the old asphalt, and leave the stones in place ? (seems almost impossible to do, I would think, but am not sure ?)
b. What should the stone bed thickness be ?
c. What should the asphalt thickness be ?
d. What's a "typical" price (per square foot, I guess) for a complete job including the new stone bed ? (live outside of Boston)
Not too sure what else to really ask.
Any other thoughts on would be most appreciated.