Geofabric under footings

[maarass]

Hello, I posted a previous queries titles Water Table Issues- HELP and How much does a house weigh? My G.C. is getting back some answers reguarding the water table that we hit at our site. He seems to think (what I heard all along) if we lay down the geofabric right on the ground in the wet mud then compact 10" of 3/4 crushed with a Jumping jack compresser and beef up the footer that it will suffice. I have the geofabric under our gravel driveway and it works good. Another excavator told me they put it down under gravel under footings when they hit ground water. Well it seems it may happen now. My experience is limited to hearsay when it comes to this stuff. Any first hand experience with geofabric (woven) under gravel under footings ? Thanks

[maarass]

Just an update for the benifit of the forum. Geotech came out and took a look at the site. He recommended scraping off the top layer of silt (the mucky mess) and at the same time laying down 8-10 inches of "clean fill gravel". He was very familiar with this area. We have to dig a sump pit first and have the stone ready and waiting. About the geotextile fabric, he said would only be really benificial for live loads such as roadways. I think someone else posted about it to. I'd post some pics but not sure how yet. Also the lime slurry would be very expensive and not help much in my situation. I guess lime is expensive now or something. Thanks

[RobBase]

Your geo tech guy is spot on. We only use geo fabric under roadways or parking lots.

The last job we did had muck under the footing elevation. We dug down 2' to better soil, placed a 4" perforated drain pipe around the entire circumference of the footings, covered it with filter fabric, then covered that with 2' of 3/4" crushed stone, followed by a plate tamper. Poured the footings on top of all that.

Should add, that this was near a hillside, so the footing drain was easy to run to daylight.

[maarass]

Thanks for the reply. Geo probed the area and said a foot will do. Geo also said to use 3/4 crushed as well. IS that different the washed gravel ? I asked about compacting and he said not nessessary and just to tamp it down with the excavator bucket. I wonder if it's still worth getting a compactor.

[Rich]

It depends.. many times washed gravel is 3/4" round rock - not crushed.