I usually hang out in Knots but I have a question that the Breaktime crowd is probably much better at answering.
I have a 100 year old house with a basement concrete floor that is a wreck. Lots of sections with big chunks of surface missing, cracks, etc. The floor is perpetually producing cement dust from the bad areas. The basement is my workshop so rolling big woodworking machines is nearly impossible.
Any suggestions? Is there any chance that a skim coat of concrete will adhere? Other product suggestions? What should I do to prep?
I’d like to avoid adding too much thickness as I’ve already got places where I hit my head on the ceiling.
Thanks in advance!
Replies
I'd use a self-levelling compound to fill the dips, sand/cement to fill the holes and fix down 3/4" ply over the whole area -- but that's just my opinion!
'Skim' coats of concrete don't work -- the minimum thickness needs to be 2" and even that takes a lot of effort to make sure it doesn't delaminate, curl or crack.
IanDG
Forget the skim coat, it will break up immediately.There are several alternatives. Remove entire floor, dig several inches down and repour new floor. I saw this last year, remove old floor, dig 4" of dirt out and place 2" of concrete sand (orange sand).Then paving bricks. This method was used because the homeowner wanted a brick floor.Whatever method you use I would remove old and loose concrete entirely.
One other possible idea, after removing loose stuff, pour concrete to replace, level off with gypsum levelers, fasten t&g plywood or osb over a vapor barrier.You will loose at least 3/4" of headroom.
mike
Thanks for the advice. I was afraid that the answer was going to be removing the old floor - but this seems to be the only alternative.