Messages and Online Forum Q&A

Re: building a patio

From: info@builderswebsource.com
Category: Other/Misc
Remote Name: 63.198.181.43
Date: 03 Jun 2001
Time: 09:22 PM

Comments

If the ground is properly prepared and compacted, concrete pavers can withstand huge compressive forces. Cars and trucks which transfer their weight to tires can safely sit on pavers without adverse effects, so long as installation is done properly.

Generally, we recommend the following process:

1) Excavate about 7.5"-8" of soil and thoroughly compact the native ground with a gas-powered tamper/vibrator. Make sure you slope the patio away from the house at approximately 1" per every 4-8 feet of length. This is essential for maintaining good drainage, which could otherwise undermine your sub-base.

2) Lay drainage filter fabric over the compacted ground to prevent the next layer of gravel from compressing into the soil. This is an optional step, but has proven to help keep patios and driveways more even over time.

3) Bring in a suitable crushed gravel (such as #5 crushed limestone or other base), compacting and wetting in lifts of 1-2" at a time. Continue compacting to greater than 90-95%. Go over the entire area at least twice for each lift. Make sure the sub-base extends about 8" past the edge of the patio to provide adequate edge support.

4) Spread and screed washed, coarse, salt-free sand (1 inch) such that the pavers are about 1/4" higher than the desired final height. Of course, we assume you've already put in place your border anchor, which could be landscaping timbers, concrete, or flexible plastic strips made expressly for anchoring the edge of pavers.

5) After laying the pavers using a string as a guide, use a flat plate vibrator to "lock" the pavers into place. Sand underneath will vibrate up between the pavers, causing the pavers to drop in height by about 1/4". Don't over vibrate, otherwise you'll have dips in the pavers.

6) After you've achieved the desired height, sweep in fine, clean sand between the pavers to finish them off.

You should now have a solid surface on which to put an above-ground swimming pool. Keep in mind, if you live in an area subject to frost, you're pavers may become uneven over time due to ground heaving unless you excavate below the frost line in your area...which may be prohibitive. In severe cases, some people build a sub-base slab with reinforced concrete. This is generally unnecessary but if done right, will provide a monolithic base that should last the life of the structure.

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