regrading, patios, drainage & bucks
Hello to all. I’ll try to make this short but I know it isn’t!
I am hiring an excavation co. to regrade the land (cutting a huge swail) so that rain water will be diverted around 2 sides of my stone house into a stream and down a small hill. On one side there are two garage doors that in which each have in font of them, a 1′ x 2′ grate over a concrete box that goes down about 3′ and that has a 6″ clay tile pipe (apparently clogged at some point) coming out of the front of the box, leading away from the house. The ground in front of the garage is a shallow depression of blacktop but the outer edge of this is about 6″ above the grade of the garage floor. Also, the area beyond the depression is blacktop that’s sloped toward the house. Are you still with me?
SO, in a light to moderate rainfall, this arrangement actually works OK–the water comes sreaming down the blacktop into the depression and the drains (if they’re not filled up with silt) drain slowly but steadily. But in a sustained heavy rain, the drains don’t empty quickly enough and a pond forms spilling into the garage.
Meanwhile, we want to make the garage (1100sf) into a studio for my photographer wife, so we thought we’d turn the garage doors into windows with doors leading out to either a stone patio (6″ above the garage floor, but the window frame would come up this high or higher on the bottom) that’s pitched away from house or a wood (Ipe) deck built 6″ up but with some kind of drainage setup underneath.
The big question is: Is it better, from a drainage standpoint, to do the wood deck or the stone patio? Is it ok to have water draining down through the deck into a drain of some kind? Won’t silt etc. eventually clog up that drain? Is it OK to have a stone patio which will send water away from the house and into our swail, but that’s 6″ above the garage (studio) floor?
Thanks for listening, Rob
Replies
While your excavator is there, you might want to have him dig up the drain tiles that run from the catch basins. Replace them with solid PVC, at least 4" diameter -- 6" is way better. And be absolutely certain that the pipe is sloped sufficiently into the swayles, or over the side of the hill. The more slope, the better to keep the silt and leaves washed out.
Then you should consider the net effect of having an outside "floor" that is 6" higher than the inside floor. Sounds to me like a recipe for minor flooding at some point. You might want to convert the garage floor into a crawlspace, or lower the exterior grade. Then you could use whatever patio material suits your fancy.
Thank you very much. I thought about bigger pipe but I didn't think about the velosity of the water (& the other stuff) to help keep the line clear, which is what you're saying with having more pitch. Who said you're just a yes man? --Rob