How to install a rubble trench correctly

Hi Everyone,

I have a question that I can't seem to find the answer to. A rubble trench foundation seems to be ideal but there is a problem with them. They incorporate a French drain along with the foundation trench. (See Pic) The problem also arises when dealing with a permanent wood foundation with plumbing lines. How do you provide support for the building above (via compaction of the foundation material) while not damaging the 4" PVC drain and allowing proper drainage? Contractors who deal with backfilling problem basements after putting down drain tile would never use compacted gravel around a PVC pipe. Most would say to use compacted soil free of stones but that would completely plug up the French drain. Permanent wood foundations usually cover the plumbing lines with 6" of gravel and then use a plate compactor. Since most plate compactors are not that big and only apply a limited amount of force I can see damage to piping being not a big concern. If I was using a Jumping Jack in a rubble trench that PVC pipe would be toast.

Thanks Y'all

I would think sleeving the drain pipe with one of those sock things and then using a foot of sand around it before filling with gravel would protect the pipe and keep it from clogging.

In my house, which I did not build, the drain pipe sits to the left .

Hi Jp!

I'm not a builder or engineer or anything like that but I was involved in a large part of building my home, starting with the footing. Maybe having a french drain directly under the point load of a footing could be done in some areas under certain conditions, but I am unfamiliar with it. I can see how if the french drain pipe began to collapse under the weight of the structure above, then everything above it will begin to settle as well and could pose serious threats to footing and foundation wall integrity. In Tennessee, foundation and footing drains are placed to the exterior of the footing as shown in the attached graphic. It's what I did on my home. Rigid 4 inch PVC was used, the kind with holes about the size of a quarter in them, and this was run around the perimeter with a gentle slope to a common exit. The pipe was then covered and entombed with #57's crushed limestone gravel. By placing the french drain to the exterior side, the same water conveyance will be achieved without the weight of the point load forces from the structure compromising the footing and everything above it.

Jp I've been wondering about the same issue.

Running water and greywater pipes into the house. Which I suppose would be no big thing if frost wasn't an issue.

Anyone with ideas or experience with that?

I was confused about this very issue.  James where on Earth did you find the smooth wall PVC with holes?  And did you line with geotextile fabric?

I think James is talking about a product called septic leach field piping.  Most building supply places have it or can get it:

Home Depot link

You know when I looked at the septic pipe before I thought it had too many holes.  But now I see you can select it with two holes.  Thanks!