In an effort to reduce this overall moisture under my basement floor and walls, I am installing an interior weeping tile. My foundation walls have no footing (this is known from foundation repair and exterior excavation last year). The bottom of the wall is at the bottom of the floor slab level. The contractor will dig a trench 1 foot wide and 1 foot deep. The question is: How far from the wall should this trench be (again noting that there is no footing)? My understanding is that the rule is 1:3, i.e. 3 feet away for 1 foot down so as not to undermine the foundation walls. Of course, the trench will contain a sock-covered weeping tile will appropriate gravel all around. Additionally, I would like to run some "tentacle" trenches, i.e. pieces of weeping tile perpendicular to the wall in order to get closer to the wall than the "main loop" described above. These would run from a T-connector on the main loop and then perpendicular towards the wall. If we want to put these tentacles every 5 feet, then how close can I go to the wall? An engineer indicated approximately 1 foot away from the wall for these 1 foot deep tentalces, although I think this was just a guess. Can I go closer, or even right under the wall itself? This would be 1 foot dug for every 4 feet existing earth, etc. Note that my soil is about 80-90% sand content (from using a simple jar and water test). (Note that I am installing the interior weeping tile because I still have some wetness on the interior of the basement wall after an exterior foundation repair last year. This included full mortar repair, waterproofing and membrane down to bottom of wall, and insulation. Due to there being no footing, of course digging could not go below the wall and hence weeping tile level is not below wall - and bottom of wall happens to be floor level. The result is that some wetness is now "wicking" up the bottom of the wall from moist soil underneath. The objective of the interior weeping tile is to generally lower the moisture content at that level, although it is understood that the problem may not go away 100%.) Thanks.