Footing Drain C33 Sand + slotted pipe. 1/2gallon discharge per minute.

[For The Good-Solutions.]

I installed about 75ft of slotted cheapo pipe and c33 sand around the back and side of a fixer upper house. The other day we had snow melt and rain. I recorded a max of 1/2 Gallon per minute of very clear water coming through the discharge pipe where it daylights into my creek. I stuck a temporary fitting on the outflow so it would fill up and spill over for me to measure the discharge.

I was very excited to see the footing drain work. I have never lived in a house where I could see the discharge point.

I have always hated buying filter fabrics. After studying Oldestguy's c33 sand discussions I was convinced it would work great and it does. I'm not sure what the flow would be with larger size aggregate and filter fabric, but I'm happy with the results I have and how easy it was to install.

My foundation here sucks, it's not as tall as it should be and I am pretty sure there is not even a footing, at least not on the outside. So I opted for the c33 sand style drain because I didn't want big air voids using drain rock. I had to cap it with backfill to also keep cold air from dropping down easily and freezing the soil too deep. I had to keep things very minimal as far as depth and amount of sand around the slotted pipe.

Figured I share since I have results that I can measure. Thanks Oldestguy for sharing the old school wisdom.

 

[EireChch]

Glad it worked so well. Credit to OG. Would like to see him back active!

 

[Milliontown]

There's a reason we keep stockpiles of C33 sand on our dam sites for emergencies. There's not really a better gradation material for filtering soil, outside of extremes in coarse and fine grained soil. Even with some of the clay foundations I've worked on with >90% passing the #200 sieve, the C33 didn't meet filter criteria strictly, but laboratory testing showed pinholes clogged and eventually filtered the material. Plus it is so readily available I almost always spec it for filters. My only caveat working on dam safety projects is we required the C33 to not contain limestone. It's a small risk but there is a potential for the material to cement and clog the filter.