Years ago my basement was waterproofed on the inside by the method of breaking up the concrete, digging a trench next to the wall then laying pipe and adding gravel over the pipe for drainage. Then they covered if up with about a 1/2" (give or take, i'm not sure exactly how thick it is) layer of concrete.

My question is, If I want to attach a framed wall to this section of concrete, will the tapcon screws work on concrete that is on about 1/2" thick or does it have to be thicker. I am not sure if there is enough there for the screws to grab onto.

If you don't think these screws will work is there any other way to attach the wall to the 1/2" of concrete.

Thanks

 

bobstar,

You can use your tapcon screws as these will prevent any lateral movement. This is better than using a Hilti or pounding nails. You won't need many, like every 4' O.C. is more than enough. It isn't so much a need for grabbing power as it is to prevent movemnet side to sdie. If you want, place a little construction adhesive under your W/T plate.

Hope this helps!

 

I think you are asking for a moisture problem by putting a hole down into a drainage bed. Tapcons do not provide a watertight seal and moisture could easily move up into the bottom plate. While the plate should be pressure treated, the moisture can easily wick into untreated wood if the plate becomes wet. I would consider fastening a steel bracket to the wall and then securing the bottom plate to the bracket.

 

brickeyee,

Since bobstar has an interior drain tile system installed, it is not going to create problems with wicking as the 4" drain tile itself is covered with pea gravel then concrete is patched in to existing floor level height. The drain tile is directing any water that it collects and taking this to the sump basket. The installation of these screws will not create a "gusher" as you seem to think it will. His drain tile is apparently functioning properly. The use of the screws is a better option than using nails and hammering, if in fact the concrete is 1/2" but I think it is more like 1" to 2". Even still, screws are only for the purpose of preventing side movement.

Fastening a steel bracket to a wall could do more harm than good. I have done that and to my surprise, I had a flow of water come out - not a nice thing to see.

Bobstar has a good idea and will work fine.

 

If the gravel bed fills up for any reason he will have water intrusion. Take your chances as you wish.

 

brickeyee,

Theres no way the gravel bed would fill up with water, as the water would fill up the sump basket first. There are very rare cases when silt blocks holes in the drain tile but again we are talking allot of holes that would have to be filled to create this problem. Bear in mind that the 4" drain tile and the bed of gracel is below the already top of the existing 4" of concrete. Gravity does work wonders. Look at this, for a better understanding of how the system works,

http://www.dspinspections.com/basementwater.htm

http://www.absoluteconstruction.net/wetbasements/

I've installaed this myself and for all those basement projects that have been remodeled and clients had the system installed, not one ever had problems that you are presuming would occur.

Just thought I'd help educate everyone on how these work.

 

I understand how the system works. If the bed fills up the water comes in. If the power is out, the bed fills up, the water comes in. you seem to have to strong an assumption about gravity. Moisture will move by capillary action against gravity for a significant distance. The propsed holes will penetrate into a drainage system. If the system fills for any reason you have created a source for leakage.
You could probably drill a 1/4 inch hole in the vent stack down in the basement. Gravity is making the water drain. Why would it ever leak?