Blog Archive

Wednesday, July 1, 2009

How to Build a Patio in Expansive Soil: Part III

Monday, June 15: After about 18 hours in the summer heat, the concrete was cured enough to remove the forms.

My dad made notches for the treated lumber to slide into. Here in Davis we have expansive, clay-rich soils (vertisols, if you must know). This means that in the winter the clay absorbs the water and expands. Then, in the summer it dries out and cracks, much like in the desert. So most concrete walkways, driveways, and sadly, slabs that most houses sit on (Davis houses don't have perimeter foundations) are all cracked. To avoid having a cracked patio in a few short years, we decided to use lumber edging instead of concrete.
Since the yard is sloped (a good thing, for drainage), we used 2"x8" for most of the edging and then 2"x10" for the others.
Not much else on the patio was done that day. Dave and my dad decided to redo the concrete guard they'd built a few months ago under the front yard 6' wide utility gate. I don't have pictures of it, but they basically extended it outward, ramped it to facilitate driving the boat trailer over it more easily, and increased the height so that it meets up with the bottom of the wooden gate. We call it the "Nose guard" since it is there mainly to keep Potatoes (aka, Noses) from digging his way out of the yard.

We also went to Home Depot and bought the paving stones. If you want people to stare at you, I recommend loading 480 paving stones into your car and trailer in the middle of a hot afternoon...while very pregnant. The sales guy gave me a quizzical look when I told him that my dad and I could handle loading them ourselves. To reassure him I said, "Don't worry, this is just a watermelon under my shirt."

Tuesday, 6/16: Once the treated lumber was slipped into place we all--yes, me included--began hauling in wheelbarrows full of aggregate base (aka, road base) into the patio form. Dave calculated that we'd need 3 yards (that's about 9000 pounds!!) of base once it was compacted.
Edward flew in from Pittsburgh that morning so I went and picked him up at the airport while Dave and my dad finished hauling the base.

Once it was all in place, it was raked out evenly. Dave used an extra piece of lumber laid across the patio's edges as a skive to evenly spread the base out. (That's the wood you see at the bottom right of the picture.)
Poor Edward had been up since 2am California time traveling but his fatigue (read: his insistent sister) didn't stop him from helping out with the tamping.
While Dave was manning the tamper I was chatting with my dad. Then I realized that he was just distracting me so Edward could take candid pictures of my big belly. Har, har, har.
Then they used the vibrating plate compactor to make a very smooth surface. The smoother the better in this case because we put down a layer of fine sand afterward.The sand was only about 1" thick and was made completely even and smooth by using a skive and wetting it down before tamping.
This made a perfect surface for laying the paving stones...which, after all that hard work that day, Edward and I started doing as it was getting dark.
Once the mosquitoes came out, we went inside.

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