Page 1 of 1

basement floor - control joints

Posted: Wed Dec 06, 2017 8:32 pm
by 49wjd
My basement project required relocation of the rough-in drains placed by the builder, and thus a section of the concrete floor was removed. That section of concrete contained the intersection of two perpendicular control joints. How important is reconstruction of the control joints when the new concrete is poured?

Factors that may (or may not) be relevant:
- house was built 3 years ago, foundation and basement floor poured about the same time
- radon levels were elevated and mitigation system is in place
- the new concrete will be covered by combination of shower base, porcelain tile, walls, and carpet
- house is built on expansive soils

Re: basement floor - control joints

Posted: Wed Dec 06, 2017 9:30 pm
by Shannon
The control joint lines really are not needed in the new portions. IMO. Everything will be covered with flooring so it should not be important.

Re: basement floor - control joints

Posted: Wed Dec 06, 2017 11:07 pm
by A. Spruce
Control joints are used to control how large slabs crack. In this instance, pouring new concrete against old concrete gives you that same control.

The only thing you're probably going to want to consider will be to use an isolation membrane between the concrete and your tile, this way any movement in the slabs won't crack the tile.