[Ford]

_Paver, Patio Drainage Problem.

First post-this is an awesome site!

I am designing a large paver, patio for a client. The total area is about 2000 square feet.
The patio would be a 50x40' rectangle, with four 10' circles, interlocked in the center.

My problem is drainage. I live in the mountains of North Central Pa., which have strong freeze/thaw urges in the winter, so I am having bad dreams about drainage.

The soil is a good clay loam, with a harder clay base about a foot down, and drains very well. Even after hard rain, there are no puddles.

The patio extends about 40 feet along an existing concrete porch. The pavers will be laid level with that porch, which is about 6" above the existing sod. I would build a short stone wall from that point, to step down that 6", extending that wall/step 50' at a right angle to the concrete,as a border.

At the end of that proposed step/wall is an existing, mortared stone wall, 4' high. which makes the opposing border to the concrete porch.
That stone wall is 40' long, continuing to a right angle, then it returns to the house, 50', and so joins the beginning point . ( the concrete porch)

I cannot figure out how to slope this thing.

If I slope the pavers towards the proposed short wall, it will show as a gradual slope along the exposed ,6" drop of the porch. This would cause to be, no step on one end of the paver edge, and a 5" drop/exposure at the other end of the 40', considering 1/8" per foot for drainage. (In this case I would not use a step/wall at all) This seems to me both dangerous and ugly.)

Which made me consider some kind of pipe/drainage system, like a sewer grid, in or under the subbase. I can run the pipe to daylight under my short step/wall.
Perhaps perforated sewer pipe, laid in clean stone with a silt fabric on top?

Have any of you run into this kind of problem? If so, how was it solved.

Sorry for being so long winded. I tried to explain the situation in the shortest terms I could think of.

Thanks in advance for any help.

Ford


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[Stonehenge]

Maybe it's late, but I'm finding it too hard to follow your description of the layout. Can you post a sketch?

[Lanelle]

I agree. (I thought it was just me not following)
I guess we're a visual bunch.
Let us know if you have any difficulties posting.

BTW, welcome aboard and hope that you enjoy your time here.

[Raj Venugopal]

If I'm understanding you...can you account for the elevation change by embedding a large natural rock outcropping into the patio/wall? You can then account for the elevation change by butting up to the natural rock at different points, and it won't look as unnatural as a stepped down wall. Since you're only dealing with 6" your stones could be 3-4' buried 2/3rds and you'll have enough space to make the bridge.

I live and work in high clay areas. Get any clay above the frost line out, do not compact the subgrade, geotextile and lift it with crushed rock. Clay will cause you untold amounts of misery if it decides to heave on your work.

[Raj Venugopal]

Regarding drainage, we've used perforated tile with a prefitted filter sock on it with success for drainage. An engineer friend suggested installing a chimney drain extending below frost line, which is around 4' here) at the end of one driveways, which we didn't do, but might be an option for you...someone here may have experiences with vertical drainage. Daylighting fabriced drain pipe in clean stone is a safe bet in any event.

[Stonehenge]

All that was needed was to crop this pic to the appropo size.

Anyway, here's the area in question:

[Stonehenge]

Looking at this pic, you should be able to keep the pavers at a consistent height along the porch - you just need to pitch it like I've got in the pic below:

[Stonehenge]

You'll have a more gradual pitch at the bottom right of the patio, and more steep at the bottom left, all pitching toward the middle, with the middle pitched to your "water must exit" point.

[Raj Venugopal]

I've never used channel drains myself, but it could be an option too.

[Mac]

Jeff, that just gave me terrible flashbacks to one of my landscape architecture courses. Wow, the pain you can endure and then completely forget. Its amazing how our brains work sometimes.

[Ford]

Thanks all
Your suggestions have gotten me thinking, which is of course the first step to solution. Minds of experience are usually practical, in this case considerably . I like the idea that Raj has come up with, the incorporation of boulders in the short wall, to make the grade/slope look more gradual.
Again, thanks all for the help.
Ford

I'll post some pictures, if I do this, I am pretty sure I have the job, it is just a matter of doing the estimate, and figuring out the extra costs of the drainage procedure.