I would like to ask advice on where to put the 4 inch corrugated drain pipe in a paver patio wall project. Since I have had some heavy rains in the last two days I want to make sure once the patio is in that the rain gets diverted to the right place (away from patio area and into my yard). Should the drain be basically at the level that the soil and gravel start? Should it be higher and if so why? I ask this based on the rains making the soil very wet/muddy. I know that a properly compacted base and enough gravel will avoid this, but I want to attempt to do this right and last a long time.
I am in the middle of a paver patio with some small steps at one end that goes from my house to the concrete wrap around a swimming pool.
There is a natural grade going from the house down to this area. I already have in the design a paver channel drain to divert the surface water.
I am also planning on putting in a 4-inch corrugated drain pipe for base water diversion that will occur from this natural grade and from water run off near the pool concrete.
My question is at what depth should I put the corrugated drain?
Should this be at the low level in contact with the geotextile barrier?
Should this be a few inches above the geotextile?
Should this be or should this definitely not be above or below the first layer of wall block I am using for steps?
How important is fall with a corrugated drain pipe like this? I was planning on a 8:1 ratio so that it would not be too high above the geotextile fabric in the middle.
Take a look at the attached drawing. Apology for my lack of artistic talent.
The brown section at the bottom represents the soil base. Note the grade from house on left sloping down to pool concrete on right.
The purple section is the gravel.
The gray section on the right is the pool concrete wrap. Water will naturally fall into the middle of the drawing from right to left.
The yellow section is the pavers. They will fall 8:1 from the house to the red steps at the pool concrete.
The green notch in the yellow pavers is the channel drain.
The red blocks represent the 4 inch high, 12 inch wide, 8 inch depth pavers being used for steps.
The black line is the geotextile fabric (thick landscape paper like a tarp)
The green circles represent the proposed locations of the corrugated drain pipe I am asking about.
The dimensions are not to scale.
The gravel section will vary greatly. Of most notable dimensions. There will be at least six inches and most areas 9 inches of gravel base below the lowest red steps. The gravel base in the lower section for the pavers will be at least 16 inches. Closer to the house the gravel base will be at least 8 inches. The paver level will be 14-16 inches above the pool concrete.
The size of the patio is 18x48 and I am in Western PA.