Question
Hi -

I am looking to build two brick paver patios in my backyard.

One will be about 6' by 8' and will be used to set an outdoor dinette set on for eating outdoors etc...

The other will be about 3' by 4', in a different section of the yard, and will simply used to stand the grill on.

Ive been reading online articles about how to install these patios; 4 inches of gravel, 2 inches of sand, 2inch thick pavers....in a nutshell. My question(s) are:

1) Is the gravel/sand combo under the pavers used for drainage purposes?

2) How nessecary are all the above steps? Ie. How catastorphic would it be to leave out the gravel, or the sand?

3) Do the steps to build the patio change (or the requirements change) based on the purpose of the patio - one to just hold a grill and one to actually have people sit, have dinner on...etc...

Thanks.

Answer
1.) No the gravel is for compaction and provides a suitable compacted foundation that is less likely to move or compress when wet or frozen compare to topsoil in your yard. The sand is to provide a layer to work on that is easy to "screed" and level but also has the same functionality as the crushed aggregate. The pavers slightly settle into the sand and become locked into place.

2.) It depends on your soil. If you already have a sandy well drained soil (such as southern Florida) then you can probably live with out the crushed aggregates but you will always need the sand as a leveling course. However it is definitely a standard for everyone to put in the crushed aggregates. No professional would install without it. You risk movement and settlement without it. I would never define the lack of a few sq feet of aggregate as catastrophic, the worst thing that can happen is your pavers will settle and you will have to re-set them.

3.) Yes, in the case of patios only to hold lighter items you can lessen the amount of aggregate to 2-3" instead of 4" or more. Paver where cars drive over often have 6 to 8" of crushed aggregate. Also if you live in the south you can use less as frost is less of an issue.

Good Luck
Sean J Murphy, LA,ISA, LEED AP
Please check out my blogs and articles on landscape topics like this on my websites.
http://www.seanjmurphy.com
http://amenityarchitects.com