Back Filling 8'8" Basement

Hardibuilt

Hello, I'm new on here. I have read many posts before joining and find this site to be great.

I am tackling my first basement home and I was wondering how much gravel was commonly used after placing drainage tile around the footers? I know some who use as little as one foot square to others that go within a few courses of the top with all gravel. On the house I am building this range would vary the amount of gravel from 10 ton (one foot square) to around 100 ton (almost to the top). I do want to use enough gravel but I don't want to go crazy either. I understand that gravel does eliminate the hydropressure that can build up along the walls.

A little more info to help in answering. The house is on a peak of a hill with good drainage and I havn't seen any water seaping out of the walls. I am parging and using a good quality tar in generous amount. I will be using drylock on the interior wall.

Any help is greatly appreciated.

PipeGuy

In the absence of using a filter fabric around the gravel, the gravel pretty much just serves to keep dirt from migrating into the drain tile. If you use filter fabric you can reduce the gravel envelope. Conversely, if you don't want to use filter fabric then use more gravel.

If it were my house, I'd use at least 18" of gravel backfill alongside and above the drain tile and I'd cover the gravel in a non-woven filter fabric. I'd use 30" of gravel in the absence of using filter fabric.

Just as important as keeping the drain tile clear of dirt is making sure it has a good outfall to daylight. With your hill top location that shouldn't be a problem. Try to maintain a slope along the drain tile to daylight of at least 1/4" per foot - never less than an 1/8"er foot.

Use SCH-40 PVC pipe or better. The typical corrugated black stuff is subject to deterioration and certain rodents will try to eat it.

Commercial structures frequently use a drainage membrane on the exterior of the foundation wall. If it were my house I'd probably do so. This facilitates good drainage along the entire face of the foundation wall to the drain tile system.

With a proper foundation drain there should be no need for an interior application of sealant. Good luck.

Hardibuilt

I do appreciate the info and thanks to a good day of work the basement is now ready and prepped for drain tile and gravel.

I used masonry sand along the outside of the wall where the drain tile would go prior to the block being laid and the mud cleaned up like a dream leaving a clean footer for tile.

Everything should turn out nicely.

Thanks again.