"kzin" wrote in message
...

On 18-Nov-2007, "Will" wrote:

I'm trying to design a footpath for a muddy long area with poor
drainage.
Path is about 100 ft long and four feet wide. During heavy rain it
builds
up a two inch lake of water. Could someone criticize the following
design
for draining this area and building a walkway over it?

1) Dig a ditch and test that it drains correctly.

Do you mean drain by running off or drain by percolation? If the former
are
you able to maintain a slope? If the latter if it gets muddy now why do
you
think it will percolate better after digging the ditch?

We need drainage, and thankfully the area has a good slope.


2) Line ditch with plastic allowing about 1 to 1.5 feet of extra plastic
on either side of ditch.

Why? This will impede percolation if anything. It might provide a more
freely flowing watercourse if that's your intention but I doubt it's worth
the effort and expense just for that. I suppose it would cut down on

The intent with plastic was to stop erosion and possible caving in of the
trench sidewalls.


4) Lay down 1.5 to 2" thick flagstone, approximate 2 foot square slabs,
along the path, left loose on top of drainage rock and pressed down to
settle flat on that rock.

You'll want to top the drainage rock with sand and tamp it down well to
provide a solid level surface for the flagstone.

What about using Pea Gravel instead of Sand as the top layer above the
drainage rock?

Would we need to rent one of those big rollers that is used to compress
material? What's the best procedure for making the top layer as
compressed as possible?


That's very thick flagstone. Flagstone I'm familiar with is more like
1/2"
- 3/4" thick. Using the thicker stone will raise the cost quite a bit and
be that much harder to install (weight). Any reason for selecting stone
so
thick?

What is the appropriate thickness to support a 300 pound person (let's use
that as a VERY worst case).

--
Will