I hate being the guy to squelch anybody's enthusiasm, especially when it comes to a nice size patio project, but unfortunately things aren't always that simple. My first site visit confirmed my suspicions.
I never saw the tree while it was standing, but based on the woman's description and the enormous crater just off the back of the house, it must have been massive. What I saw was a crater approximately 10-15' in diameter, with a depth of at least 2' where the stump had been ground out. The center of the crater was filled with woodchips from the grinding process, and the perimeter of the crater showed the remains of the root system, with a network of large 6"+ roots spidering out from the center of the crater.
"I hate being the bearer of bad news," I told the woman, "but I have some serious reservations about putting in a patio this soon after the tree was removed." The problem is that all those woodchips and all the remaining root system will soon begin decomposing. And as it decomposes, the area will settle. And no matter how much gravel is put in, no matter how well its compacted, it will soon settle once again, wreaking havoc on the patio.
That decomposing/settling process can take years to complete.
So what's a person to do?
In most cases when a tree this size is removed, it's in an area far from the house. Planting another tree in the spot is often the easiest and best solution. Or turning the area into a garden can work great as well.
The problem in this case was that the tree was originally planted much too close to the house. The crater was literally right outside the back door. We certainly couldn't just leave a muddy crater there.
But for now we excavated the woodchip/soil/root footprint as best as we could, compacted approximately 8" of crushed gravel, screeded a thin layer of sand, and set the 1.5" thick bluestones atop the sand. A very typical dryset installation. How long will it last before some settling occurs? Tough to say for sure, but my guess is we'll most likely need to do a little bit of resetting in the next two years or so.
But with the dryset technique we used, any future maintenance or repairs will be minor, and the stones can be used again without incurring additional material costs. And the client gets a great walkway in the mean time. Not a bad compromise.
Quick. Simple. Effective. And expert advice too, if I do say so myself. Got a problem area in your yard that you're looking to do something with? Give us a call, and let us know what we can do for you!