[Raj Venugopal]

A buddy who did drainage work told me he switched to using pea-stone instead of 3/4" clean rock for drainage trenches....drain tile.

Anyone else do that, and my real question...has anyone used that as clean fill in a retaining wall application?

Thanks,

[Matt Kulp]

My first question would be why do you want to use "Pea-Stone" instead of 3/4 clean? We use 3/4 and up for drainage work. What are the supposed benefits of "Pea-Stone"? Just curious.

As far as the retaining wall application, you said clean fill? Do you mean fill for the drainage zone, or for the reinforcement zone? Drainage zone, I guess it would not be a problem if the gravel was the right size. For the reinforcment zone you need some filler material to achieve the desired proctor.

[Pelican]

If you're using perforated PVC pipe, you'll want to sock it, or cover it with filter fabric before using pea stone. You risk having the stone clog the pipe due to its size. Pea stone will also be slower to drain since the air space between the individual stones will be smaller than the 3/4".

The only advantage to pea stone I know of is it's a little easier to shovel and rake out. I don't think the drainage performance is on par with 3/4" or larger clear stone.

[TrickyDick]

I don't think it matters except that pea stone is easier to work with. The pore space is still plenty big enough for water flow... unless you're draining the floor of a molasses factory or something. Around here people use everything from pea stone to 1.5 inch.

[Raj Venugopal]

The fill area is the drainage zone only, and the thought was that it drains as well as 3/4 clean unless you're in a deluged area, and is easy to work with. We used socked perforated tile, and contain the drain field with fabric as well, so I'm not too concerned about the tile clogging.

[Pelican]

Has your buddy explained why he switched? I'm curious.....

[Raj Venugopal]

He simply said it worked better in the applications he used it in, and that it was easier to work with.

We used it on a curved retaining wall we did this weekend. The small peastone really did a good job in filling in the open wedges on the wall's backside.