How to get water to hop from patio over brick wall?

Question

I have a concrete patio elevated a few feet above the lawn. The patio is bordered by a brick wall (on 3 sides, with the house on the 4th) that extends higher than the top of the concrete of the patio by about an inch. Currently, the original owner's caulk has deteriorated, so rainwater flows down between the concrete and the brick, seeping through the bricks to weaken the wall and cause mildew.

In addition, the water pools and flows between the patio and the house, leading to moisture in my crawl space.

If I repair the caulk, I will have a 1-inch deep swimming pool, and the water has to go somewhere eventually.

How can I get this patio to drain to the lawn?

Ideas are appreciated!

Answer 1

I would take a 4-1/2" angle grinder with a diamond wheel and cut out the mortar between the bricks down level with the patio surface, at like 5-10 brick intervals, creating a path for the water to flow out. Then re-caulk the joint tapering the caulk at each "drain".

Answer 2

It can't go over without a pump of some sort (even a siphon needs energy input to start it), so if you want a passive solution it has to go through, by installing some sort of drainage pipe through that wall. Maybe more than one. Yes, this may require disassembling and reassembling the top few courses of the wall, unless you want to try drilling through a mortar line.

I'd make sure this was lined with a nice strong pipe, to guard against ice expansion hazard.

Think of it this way: you have a perfect opportunity to install a functioning gargoyle!

The better answer would involve a drainage system across the whole field, feeding out thru a pipe. The grading might want to be adjusted to help that flow properly.

Answer 3

Raise the patio surface above the brick, or lower the brick below the patio surface.

If you install any type of drain system. You'll have to either slope the surface towards the drains, or install a continuous drain. Otherwise you'll have puddles.

Answer 4

You could consider outdoor tile/outdoor-rated mortar, aiming for a total thickness (including the thickness of any decoupling underlayment like Wedi board or Schluter DITRA or EasyMat or RedGard) that would bring the tile surface up high enough so the water could flow off of it out toward the perimiter between the bricks. You would have to make sure the grade allows such an outflow.