"Lumpy" Basement Floors

[Tony Daniels]

Has anyone had problems with basement floors which seem "lumpy" in several spots? We're planning a basement remodel but I'm concerned that the lumps in the concrete floor (currently under carpet) could be something serious. Also, have you used flooring contractors you'd recommend?  

[TheWindyCity]

We have a floor in our unfinished basement that is lumpy.  They only poured 2-3 inches of concrete in the basements on our block back then.  Our bungalow, we determined from permits, was built in the winter, on clay soil - so water absorption is not very good.   Our theory is that that the concrete and soil below froze during construction, causing the ground to heave and crack the thin concrete in spots.   We have repaired sections though out our basement.

I have seen bungalow rehabs where they remove ALL the concrete in the basement, dig down a little further, and add the right depth of new concrete.  That might be the better way to go, as you need a solid foundation for your project.  At least you could rest assured that you would not have problems down the road after you put money into a remodel.

[Pamela Conroy]

We have no flooring covering our concrete basement floor and we have a big spot of efflorescence.  I showed it to a handyman and he said it would be easy to fix.  I imagine he will dig it out and fill in.  It is a spot about a foot in diameter and it is a little higher than the floor around it, so that could be what your lumps are.  This particular spot has been there since we moved in seven years ago and has not gotten that much worse.  The home inspector at the time was not too worried about it.  The rest of the floor has a gray paint or coating on it that seems pretty old but has held up pretty well, although there are some cracks and peeling.  We do not haev flooding issues, just a little seepage now and then.  Pam

[dcol...@gmail.com]

Hum,per Mike Holmes [Canada] on his "Holmes Makes It Right" show on HGTV and several other shows on that cable station 'lumpy' concrete is indicative of a serious issue that can expand later into high cost damages. 'Ground-freezing' and not-thick-enough' concrete foundations are most usual causes as well as water absorbency and/or 'settling'. In most cases it is strongly advised by most experts like Holmes to 1st) Discover actual depth of concrete layer in inconspicuous spot (preferably edge & center of foundation). 2nd)If original concrete layer is too thin (not up-to-modern-bldg.-codes) then prepare to strengthen & add additional layer until proper depth is attained. Holmes advises that this may requure digging up existent layer of concrete and digging further down a bit and then re-laying a new foundation. Also walls will have to be supported as this work is done. And yes, it is not cheap! But when all is done you can be assured of no future problems for the strongest and most dependent portion of your major investment. Basements, roofs and walls are crucial areas!