Friday, July 2, 2010

Summer Project: Paver Patio

Out first-time home buyers tax credit left us with some funds. We used the majority to pay down debt, but decided to spend a bit on a home improvement. Since I don't teach this Summer, it was decided that I would undertake a Project in my spare time. (Please note: academics don't really have spare time. We have time where we don't have to be in a classroom, but we are still supposed to be doing other things.)

After much deliberation, we decided to build a low platform deck in the backyard. This would be a good thing since our house came with a small concrete slab that is a) unattractive, b) prone to flooding, and c) not very big.

After doing weeks of scholarly research into decks, my will began to flag. Decks require lots of cuts. Hammering is hard. The Ms. didn't seem very enthused about my Project either. An anonymous gentleman from the Internet suggested we all (i.e. humans generally) build paver patios instead, as they are easier than decks and require less maintenance. Zounds, that is an idea.

So, we decided to do a concrete paver patio because

  1. it is more durable, if built correctly, than a deck.
  2. it requires no tedious nails or screws, nor periodic refinishing
  3. the Ms. prefers the Olde Worlde graveltas of stone
  4. the man from the Internet said it would be easier
The patio, at approx. 22'x16' would be fairly larger than the current slab. Masons cord and stakes were used to make sure the patio would be level from west to east, and gently sloped away from the house for drainage. A curved apron would make things prettier, but annoying.

In a professional job, one would jackhammer that 4 inch thick concrete slab, and haul it away, but I am either lazy, cheap, or reasonable, and so I left it. To remedy the different soil densities, the areas around the slab were excavated to a depth of 2-3 inches and backfilled with crushed gravel.

Normally, a paver patio is done below ground so the tops of the pavers are flush with or slightly above grade. We're building on a slab, so this whole patio needs to be raised 6 inches. So, we need a retaining wall to keep the pavers and delicious patio filling contained.

First we need to order materials. In the end, we had approximately 15 tons of gravel, sand, and block delivered to the driveway, with only a single trusty wheelbarrow to get it all to the backyard.

Then a trench was dug down 5 inches, backfilled with 2 inches of compacted gravel, on which the first row of wall blocks was placed... half below grade to keep them from shifting outwards.

Getting these blocks level was a nightmare. Eventually, 3 inch caps were put on top of the blocks.

Then we added 3 inches / 4 tons of crushed gravel and compacted it with a really heavy orange machine (actually called a plate tamper).


Next we used screed pipes to put down a 1.5 inch bed of sand over the whole area and place the pavers on top. The pavers are designed to be placed randomly. The Ms. thought this should be a pattern that only has the appearance of randomness. But no, the pavers are designed to be laid out in a truly random fashion.

The curved uneven shape of the patio required lots of cut pavers. In lieu of renting a masonry saw, I fit an angle grinder with a diamond blade and commandeered the jungle gym for a work bench, much to the toddler's dismay.


The pavers have small gaps between them to allow for joint sand to get in between them and friction lock them in place. 

Without joint sand: (ignore the swollen pregnancy abdomen obscuring the foreground)

We used a polymeric joint sand that hardens with water. This keeps ants and weeds from infiltrating the sand, as well as protects from rainstorm washouts. Here's a shot after sweeping sand into the joints, compacting, sweeping more sand, compacting, sweeping more sand, then activating with water.

The tops of the new pavers come up flush with the old brick step, so I used leftover pavers to make a new step.

The finished product... (although the color is washed out from joint sand residue)

Final Reckoning:

Time to complete: 4 weeks
Materials Used: 15 tons
Average Working day temperature: 96 F
Tools broken: 1
Fingers smashed: 3
Shins scraped: 3
Gatorade consumed: 3-4 gallons
Toads Displaced: 7