how to level an incredibly uneven cement basement?

rbes

I'd like to use my basement as an office, but it's very uneven, several inches off in one dip.

There's not a lot of headroom (6-7 ft) so I want to keep as much as possible. As the basement is very dry, my provisional plan is to lay 1x3 strips directly over the cement, with shims and risers as needed to keep it perfectly level, then nail 3/4" plywood or OSB on top of that.

Or would I be better off just getting cement poured into the dips and laying those fancy subfloor panels (dri-core, etc) over it?

Bud Cline

Self Levelling Compound would be the easiest thing to do with it.

rbes

That would be great, but I was under the impression self-levelling compounds would not be up to this degree of uneven-ness. The floor is so bad it's impossible to even tell if there's a gradient. One dip is about 5 inches off the highest point, and about 5 feet wide (sloping down to a disused drain) -- is self-levelling compound up to it?

sandersonandsons

From using self-leveling compound several times (perhaps incorrectly, beware) I've noticed that while it does spread out very nicely it's very difficult to use in patches but would handle and degree of uneveness. Any edge that doesn't meet a wall or a previous dumped bucket uncured will dry with a lip that's about 1/4" to 1/2" tall. I've tried smoothing this lip out with marginal results. Also, each bucket only seeks maybe a 10' x 10' to 15' x 15' area and in order to keep an uncured edge, you need to work very fast to get the next bucket ready to dump. One last point, I've tried floating the stuff and that turned out horrible. In other words, I wouldn't recommend self-leveling the whole room or basement, unless someone else knows how to make it work.

I'd recommend flash patching if the dips are small and can be filled quickly or maybe a small grained cement (like cement patcher). Use a long enough board to match the level of the floor to level the patches off. Maybe use concrete etcher and bonding agent to ensure adhesion.

I'd avoid the strips and plywood because the wood will warp over time and no matter what fasteners you use they would probably pop out eventually in that thin a wood and heavy traffic.

Being my first post on this site, take my advice lightly I suppose. Your post actually inspired me to join because I pictured a floor with horrible self-leveling blotches (flashbacks to previous jobs?).

Bud Cline

Let me be the first to second that!

Jheeeezh!

If you have dips that deep fill them with cement patch. Fill everything with cement patch and get the floor in-range then use SLC. It doesn't get any easier than that.

Sandersonandson had no idea what he was doing. Don't let his experience discourage you. His mess is certainly the exception and not the rule.

SLC's are the best thing to come along since sliced bread and canned cheese. It is very easy to work with and does an excellent job on its own.

sandersonandsons

F this forum, I'm out. I actually shared with rbes some actual advise on my experience, not just " SLC's are the best thing to come along since sliced bread and canned cheese." How useful Bud Cline.

You know, doing home remodeling on my own since I was 16 (and now being almost 24) and being trained since I was old enough to hold a mud knife, I regret you saying I had no idea what I was doing. I hope you drive a really big F-350 because you're obviously lacking in some area, including usefulness to this planet, Bud Cline.

rbes, good luck on the project. I thought a DIY forum would be the place for someone like me, to share my less trained experience with others as well as learn some actual useful knowledge. As I feared, the trades business really is done by jocks who couldn't play sports and they apparently infest this site. With that, F this, I'm out.

Bud Cline

Another inexperienced hot-head!!!

Folks do come here to learn but taking the advice of someone to NOT DO SOMETHING based on that someone's failed attempt would be an even bigger disaster than the fiasco mentioned above.

SLC's are by far one of the best products to come along in a very long time. They work. They are very easy to work with. They do an excellent job with a minimum of effort. The results are most acceptable. If you can read the instructions and follow the instructions you can't go wrong. THAT'S my experience with SLC's. To try to scare-off someone isn't at all reasonable to me. The problem was likely with the do-er and not the product.

Even the use of the language displayed here on a family forum tells me a lot about the guy TRYING to use the product. Eight years in remodeling hasn't seemed to have taught you a thing my friend.