[Tim C.]

I am going to be building a raised paver patio for a customer. It is going to be surrounded on all four sides. One side will be the house and other three sides there will be a two foot tall knee wall . The only opening will be for a four foot wide stairway.

I have built raised patios before, but none surrounded on all four sides.

So, my question is since I will slope patio away from house and toward wall for drainage, should I put some kind of drain or rock buffer between the wall and patio for drainage or will water just drain down through the pavers? I am worried that the water will end up pooling up where patio abuts the wall.

[Matt Kulp]

The water will drain throught the pavers some. What type of "knee wall" are you building? Will it be dry laid or wet set? If it is dry laid you will get some drainage through the wall due to the cracks between the block. Another option we have used would be to use a slot drain. You can get these drains as small as 1" wide and we then paint them to match the pavers or wall. You can also have the pitch go to a far corner and put a surface drain.
I am not sure it you want to do the "rock buffer", I would see some setteling issues arising. JMO

[HardDaysKnight]

What kind of siding is on the wall?

[ecoscapes]

I Know this is an old posting, but I wanted to put in my 2cents. I think you should have the patio over hang the wall -- It give a much nicer look. Put a slope on the whole patio and the wall. compact very well behind wall and install typar fabric on top of the block wall and under the bedding sand to keep the bedding sand from leaking out. glue down all the pavers that sit on top of the block.

[ckcland]

I usually leave a 1/4" gap every 2 to 4 feet on the primary paver level course of wall block. These gaps are mostly unnoticeable and serve as weep holes for any excess/heavy rainfall to migrate outside the sitting walls. Also, make sure the water can run once it flows outside the project.

[Pelican]

In essence, your knee walls are retaining walls, and I follow the the recommended method of installation for retaining walls in this instance. Directly behind the blocks, I put 1' of clear stone, covered by filter fabric and separated from the base material in the same way. This gets compacted the same as the base material and my sand course gets laid on the filter fabric on top of the stone.

If possible, a perforated PVC pipe should be installed at the base of the stone and exit at some point through the wall. This will relieve any hydraulic pressure that could develop due to poor drainage, and will minimize any tendency for a frost push to the wall.