I have a 125 year old townhouse with a large (700 sq ft) basement. We had waterproofing done (vapor barrier, perimeter drains, sump pumps) last year that dried everything out and made the space usable. We would like to finish the basement by adding walls and a floor. The problem is the relatively thin concrete slab that has a few spots where it swelled up, and other spots that go down, mostly in the range of 1-2 inches. I was able to knock down the highest spots with a sledge hammer, and can patch those as necessary. But I’d like to put down a vinyl plank floor and don’t know what the best way is to level everything. Self leveling concrete seems like it would work, but it would be expensive. A full subfloor with shims is an option, but that seems excessive too. I don't really care about it being actually level – I just need it flat enough for a vapor barrier of some sort, thin underlayment and vinyl plank. What’s the best option for topping old concrete in as needed between 1/2 to 2 inches? The floor right now seems stable – most of the issues were moisture related.
Concrete – Leveling options for bumpy basement floor
basementfloorlevelingself-leveling-concrete
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Honestly if you have a contractor talking about basement flooring in a basement were there is a fear of moisture I would fire him on the spot if he mentioned installing real wood floors. Even in a basement with no "water" problems the humidity levels can reek havoc on wood and warp it. I see a bad wood install in a basement a couple times a year. I can't tell you the last time I saw a good wood install in a basement.
XPS and plywood can work in a lot of cases. However most of the time we carpet over this type of install. For real vinyl click lock - the good kind that is thick and pure rubber... we slap this right down on the concrete with no barrier per manufacturers instructions. If you give me a link to the flooring you are getting I can get more specific.
ok guys, here's what I did. Of the highs and low spots, I found that there were a couple dips that were significant, by the door and by the stairs/bedroom. I filled both of these in with SLC (self level concrete) and the results were pretty good.
Suggestions:
- follow the directions exactly, do not over water, it will be too runny.. I used 5.5L/bag and it worked out somewhat perfect.. I had a couple of dry clumps that some how got missed. I had to scoop them up with the trowel and re-mix them with some water. I would recommend that you get a stir stick and check the mix before dumping to make sure that none was missed. I was using a paint type mixer and I think that an egg beater type would have been better.
- get the straightest 1x4x8 and uses a screed. This is how id did SLC by the back door. The screed will slide along the high points and will push the material along, creating a perfect amount of SLC. Touch ups or moving smaller amounts of SLC with a trowel. I then feathered in the edges using a clean push brush.
- Find some soccer cleats as it will displace the SLC way less than walking with a boot. You won't even see your foot prints after walking through.
- don't freak out about this. If I can do it anyone can.
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Best Answer
Leveling compound really is the way to go with this job, are there any tricks to save money on doing it - I am sure there might be. But it is always cheaper to do it right the first time than to do it right the second time.
This is the area where most people make the mistakes : COSTS. To do something right costs this much and they don't want to spend the money, so they do it wrong, later they have issues and wish they had done it right - some then ask a pro to come in and do it right (More money) others tear up what they have and do it right the second time (More money). Then you have the others who simply sell the house to an unsuspecting soul and go their way, possibly to make the same mistake in their new home and never learning this simple rule..
Cheaper to do it right the first time than to do it right the second time.
I know it will cost you up front, but in the long run it will be cheaper both in terms of laying your flooring and having it right. You could even put heating elements under the plank if you were so inclined.