Sorry for my choice of words yesterday. Hope this is better explained: ground water flooded two finished rooms in my basement. Took out rotting, mildewed drywall, studs, sill plate, insulation. A contractor dug a trench 10" wide in the floor at the base of the exterior walls, installed a floor-to-ceiling vapor barrier that drains any/all incoming moisture into that trench and out via a shiny new sump pump. (For the first time in 30+ years, no water ingress.) Now, I'm replacing those walls. The trench the contractor dug was about 15" deep, lined with gravel, fitted with a porous pipe, covered with more gravel and finished with a layer of cement - how thick? Maybe an inch or so... There already are some cracks in the stuff. But the gravel/pipe combo is working very well so no problems yet. Except I need to put down a new sill-plate on the floor and am concerned that trying to drive anything into this cement will shatter it. So I want to use liquid nails. Think I can?

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    I take it these are interior walls since the exterior are attached to the wall with out a plate. If you have a very tight fit on the wall liquid nails might help but a couple cement screws or nails would be better they don't have to go deep they are there to keep the wall from being knocked out of place. With dry/ living spaces I put the plate directly on the cement, just as we do the carpet or other flooring. If there is any chance of the exterior walls weeping do not take the sheet rock all the way to the floor or you will trap moisture and start the rot problem all over again. – Ed Beal Jun 28 '16 at 13:06
  • liquid nails won't last... after say 3-5 years, the glue will lose it's hold. – Ben Welborn Jun 28 '16 at 13:09
  • In most cases I agree with Ben but the last home I remodeled the daylight basement had the exterior walls glued in place I ripped it all out so I could add electrical. They were almost 30 years old. – Ed Beal Jun 28 '16 at 13:12

I wouldn't recommend bonding sill plates directly to a concrete floor. Any wood in direct contact with basement concrete is asking for trouble. Concrete is porous and will wick moisture to anything placed on top of it. In order to prevent moisture wicking into the sill plate and consequent danger of mould, mildew, and rot, it's better to lay a 12" wide sheet of 6 mil polyethylene vapour barrier between the concrete and wood sill plate, then fasten sill plate to concrete with tapcon screws. Wrap the poly up on the inside of the drywall (if you're finishing the walls again) to also protect the drywall from wicking moisture from the concrete.

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