Patio regrading
by Erika
(Dallas, TX)
Our brick patio is rippled and causing significant drainage problems. There are two large trees growing out of the center of the patio. The patio should be regraded and everything raised 6 to 8inches with a slope away from the house. If I regrade the patio will be above the foundation line and the steps that lead up to a door will be partially covered. What do I do?
ANSWERHi Erika,
Your patio should not be above the foundation line. It should ideally be 8 inches below it. That is not always possible for various reasons, but definitely do not raise it at the foundation if you only have 6 or 8 inches to spare.
What you need to do is work from the elevation where the patio now meets your foundation. Slope it away from the house at a minimum of 1/4" per foot (even a bit more would be fine). Once that is done, I will assume the outer edge of the patio will now be below your existing grade. This area of the ground must be re-graded away from the patio, also at 1/4" per foot.
For what distance it should be graded away depends on other elevations further out. I don't know the lay of your land, but then you must lead the water away. This can be done with a swale or a perforated pipe along the edge of the patio which would lead elsewhere. A swale is a drainage ditch that slopes to take the water away to a designated area. This might be a lawn drain, woods, etc. A perforated pipe must lead the water elsewhere also. It might connect to a solid pipe beneath the ground and lead to a drain, woods, etc.
Either way, re-grading of your land will be necessary. Let me know if I can be of further help. I have had drainage issues myself and research is needed to find the correct way to handle your individual problem. Regardless, you will most likely find these pages helpful.
Landscape GradingLawn DrainagePerforated Pipe