GIMME SHELTER- Time tested: Dry-laid stone, brick are best
Q: I'd like to replace my worn-out outdoor patio with new brick or stone. What's the best way to go about it?
A: In Virginia, we have an existing freeze-frost factor, so you want to accommodate the environmental circumstances with whatever project you're creating or making a foundation for. If the slab or the mortar has decayed or cracked, winter water gets down in that crack when it rains or snows, then expands as it freezes and enlarges the crack each time. The bond between the mortar is now in a state of decay, and that will break the bond between the mortar and the stone over time.
I suggest laying a stone patio or a brick patio without mortar. You can create a very accommodating footer by using a gravel bed tamped down hard. Whatever the circumference of the existing patio, you want to make your dig a foot wider to accommodate the weight distribution of the stone and the watershed. The thickness of the stone will dictate how high you bring in the gravel. You can then decide how you want to border it–- with wood or a plastic liner. You can lay the stone by yourself if you run a string line. Start at the corners and then do the perimeters first.
Doing a patio that's like a watershed simply works better with the environment. The gravel below will wick the water away from your surface instead of causing maintenance issues over time. The same thing goes for brick–- you want to make the joints between your brick very tight so that you can sweep sand between any crevices and then there will be no movement.
Q: What about prevention and maintenance for my patio?
A: I would definitely inspect to find cracks in the mortar. Look for shifts in the integrity of the mortar. Then study to see what's causing them. Even if they're really small, it could be a root structure, for example. You could get a landscaper to see what can be done to control the roots, then go to the source of what's causing the cracks– maybe there's a gutter that's not following the right path that's causing erosion. If we take the time to align ourselves with nature, things will go a lot more smoothly.
Q: What about the upcoming Downtown Mall renovation? Is it better to replace the mortar between the bricks with a system of bricks set in sand-swept joints?
A: Yes. As time goes by, there will be fewer problems with the mortar cracking. They just need to really pound the bricks into place with rubber mallets. The dry-laid concept is time-tested. It's why a lot of the structures and projects that were done thousands of years ago are still standing: Mayan temples, the beautiful old squares in Europe. Time was taken to do it correctly and smoothly without mortar. You always want to do it in a way that the stone is placed upon stone instead of relying on mortar to hold the stone in place. Use the weight of the stone, and the shape of it.