driveway pavers installation help needed

[grumpy]

I am replacing 50-years old asphalt driveway with pavers. Talked to several contractors in my area. Some are insisting on excavating down

8 to 10 inches and then backfilling with crashed stone or "QP" and compressing it with a roller. Some are saying that excavating down 4 inches and compressing it with a "jumping jack" is enough since driveway has been in place for so many years and that excavating and backfilling will only make it worst by disturbing existing very solid base. While I don't want to pay more money than I have to, I want to make sure that I am not going to end up with uneven settling pavers all over the driveway. Please help, any advice is appreciated.

[SQLit]

Depending on the traffic 4-6 inches should do the trick. If you have an 2 ton truck or motor home better go deeper. You may never be able to back an cement or dump truck on the driveway. I would not use an jumping jack, I would use a plate vibrator. Jumping jacks are used for trenches, at least around here. Trick to the installation will be the grading of the sub-soil and new compacted material. You surely want it to slope so that there is no standing water on it. Check with some folks locally about weather and wear before jumping off into the project.

[Will Niccolls]

It depends on the stiffness of the existing base soils, and expected moisture content. You can get a soils test relatively cheap considering the peace of mind it provides. Ask a soils test lab to do a modified Proctor test. Pavingstones make a fantastic surface that should last 100 years if installed on a solid base, a crappy surface if they spread and collapse on a mushy base.

In the clay soils of our area (Northern Virginia) 10" to 12" of compacted aggregate base is standard for driveways. On old gravel drives that have been driven over for many years we can go with 6" of base. Costs do add up fast when you have to excavate, haul and dispose of more than a foot of excavated spoil.

As the other poster pointed out, jumping jack or rammer type comactors work best in confined areas like trenches or next to a footing. For a driveway with more than a 500 s.f. or so we find it more efficient to drive a vibratory roller, 10 tons of centrifugal force on the base. Most hand pushed plate compactors can't compress more than a couple of inches of base aggregate so make it very slow to do the job in layers. The 10T roller compresses 6" or so and goes much faster.

Check

for more info.

Will Niccolls

[Greg]

If you can pick that asphalt off somewhat surgically the base under it should be fairely well compacted. I think a little manicuring and hitting it with a plate compactor should do. I suppose it all depends on your local dirt and what they did for the original driveway.