Just finished (before winter frost) putting in the modified base for a paver driveway. I put the base in nice and deep at 12" and want to let it go in and out a few frost cycles (philadelphia) and then put the pavers (1,000 sq ft) in come spring.

My question is whether or not 2 3/8" thickness (3x6, 6x6, 6x9, 9x9 modular sizes) pavers is adequate for a driveway or do I need to move up to the big 3 1/8" ones? The driveway is residential for cars - no garage so cars will be parked on the surface (SUV and sports car). I was told by some as long as the max paver length divided by the thickness is less than 4 - I should be ok; but others have said go to the thicker pavers - any concensus?

 

You could get away with the 60 mm (2 3/8") to save a buck or two, but since you are using your own free labor, you are still cheaper than other materials and add more value. The thinner pavers are fine for patios and lightly loaded areas.

The 80 mm (3 1/8") pavers are used for streets and the 100 mm ( 4") are used for airport taxiways and major ocen-going ship unloading facilities, but these are usually installed over controlled well compacted base. Do not forget the 1" concrete sand setting bed. The base compaction to match the sub-base is often more important than the base thickness. You must sweep masonry sand into the joints and vibrate the driveway well for leveling and create a good interlock. I am not a great fan of polymeric sand because often the interlock is not that good. I have rarely seen polymeric used in a critical application.

The pattern and shape of the pavers also add to the stability. A "zee" shaped or irregular interlocking paver in a herringbone pattern or running bond give very good stability and load capacity. The larger (wider and/or longer), antiqued pavers in a random pattern will give less stability.

If you have a quality paver, it not question of cracking, but stability for the base since a paver driveway is designed to be a "flexible" pavement and not a rigid pavement like concrete that is subject to cracking. In your general area, you have several good manufacturers of pavers with access to technical support, including the Interlocking Concrete Paving Institute (icpi dot org.)

Dick

 

It's all in the base and it sounds like you have provided a good one consisting of 12" of compacted 22A crushed gravel. 2 3/8" pavers are plenty adequate. My sons and I constructed a niceriveway of 2 3/8 " brick pavers. The guys driveway was at the end of a dead end street so every truck that came down the street ended up backing into his drive to turn around. Since I lived across the street I had occasion to keep track of the drive way over the years.

In short, this driveway of 2 3/8 brick stayed nice and flat for the last 17 years as it was built in 93. I always killed sprayed any dandelions pronto if they dared air their ugly mugs. I can only recall replacing one paver that cracked. In addition we had another can of solution we kept the ants in check with as it was a sprayable insectacide. Left unchecked ants can excavate too much of that nice 1" layer of screeded sand we worked so hard to preserve beneath. The site of this home was basically a sandy Dune area

Good luck with your job.

bullshooter5