85 Year Old Concrete Floor - can it be leveled?

[TimInChicago]

Hey guys - I'm pretty new to this site as a poster but have learned a ton reading it over the last year - thanks!

I've been building my collection of shop tools at a pretty good clip over the last year or so - (spending my money now before we start having kids!) During this time I've had a small ugly shop in the basement and it's just not big enough anymore. So, I've moved everything out, relocated the washer and dryer, and am taking over what used to be the laundry room as an annex onto the old shop space. I'm starting from scratch to rebuild a basement shop.

Here's the rub - the poured concrete basement floor, original to the house, is 85 years old and really showing its age. It's cracked, heaved and generally uneven - not a good recipe for a woodshop.

I'm looking for some advice on levelling a concrete floor. I've looked at the BORG and others places but all the products I find seems to be designed for prepping a surface for tile or some other floor covering.

These old houses don't have much headroom in the basement either so vertical space is at a premium and in looking around it seems that an all-out repouring of the floor would take a few inches or more to do it right - that's too much vertical realestate for me to give up.

Anybody done something like this? Any and all advice is much appreciated. Thanks in advance!

[Scottydont]

They do make self leveling concrete but it's a bit spendy buying it by th bag. Try contacting a concrete supply vendor and see what they might have for you.

[JohnnyTest]

Could you give us some idea of the size we are talking about, also I'd be interested in knowing how far off the floor is.

Another idea would be to basically build a wood floor slightly above the concrete and have that level.

Alot of the desision has to do with the size of the room in question.

[twistsol]

My sister had a house with the same issue. The consensus from the contractors we talked to was if the floor has moved, or is conitnuing to move, it won't make a good base for a new floor and you'll end up with the same problem a few years down the road.

We ended up breaking up the floor with sledge hammers, removing about a foot and a half of dirt and putting in a foot of compacted class V and repoured a new 4" floor. We gained about two inches of ceiling height. It gaveus the opportunity to put in a drain tile, vapor barrier and sump basket.

[TimInChicago]

Incredible - thanks for all the input guys. Even with the annex of the former laundry room, the shop still won't be that that big (compared to what I'm sure a lot of you guys are used to) - it will be about 12x22, so 264 sq ft - give or take.

If I do anything too dramatic I'll run into trouble at the doorways into the shop and, I suppose, there's the pitch to the floor drain that I need to consider. At most, I would say the low spots are low by an inch - granted that's a lot.

I would love to do what twistsol did at his sister's place - pound out the old floor and put in a new one, but I fear that's probably beyond the budget at this point. I can spend some money on this (improves the value of the house, etc), but that sounds like a 5 figure project. I'm thinking a structural engineer, permits, etc. - ouch! twistsol, did you have to do all that? Would you be willing to share the ballpark cost of that project?

Thanks again!

[JohnnyTest]

I would try to basically build a sub-floor. You could glue down furring stips to the floor and then lay some tongue and groove sheets on top. Obviously the challege would be to make the cuts so that it adds enough to each part of the floor over the length of it.

[twistsol]

We did this about ten years ago and it cost $3,500 to have the new floor poured and about $500 more for everything else. The only structural part was that we put in footings for four posts where there used to be three rotting posts each sitting on a thick piece of limestone. We did that with a portable cement mixer and I think we used about 60 bags of ready mix. We used steel jackable posts and were eventurally able to level out the first floor. I used to have about a three inch sag.

The rest of it was almost pure physical labor.We (my dad, her husband she and I) did the rest of the work. Digging out the old floor was all done with sledge hammers shovels and buckets ... sort of like Hogan's Heros. My sister did all the plumbing for the drain tile, sump, and a basement bathroom (she's taken guys).

I'd guess you could squeak in under 5 figures if you did it all yourself. Concrete is supposed to go over $100 a yard by the end of the year around here. I'd imagine the rules and regulations will cost you alot more in Chicago than they cost us in rural Minnesota.

[r.palmer]

Use A laser level, and check the level of the entire floor, noticing the high spots, low spots, with all the rotten crap remeoved, and the place clean. See how bad it REALLY IS, look for leaks, wetness, anything that is coming down from above, and deal with those issues first. Sometimes getting rid of the worst high spots with heavy labor first, is a big help, if it gets you an inch before you deal with the solution, short of removing the floor.

[TimInChicago]

Thanks guys - as you can tell from the time of this post, I'm literally losing sleep over this. You have presented me with some good ideas though. Thank you.

I put the laser level down and it turns out that I've got a little more ground to make up than I had originally thought - up to two inches + from very high to very low areas. The problem is a floor drain in the center of the shop area.

Well, that's not the only problem - I neglected to mention that I do get some "seepage" into the shop when my neighbors or I don't clean out the gutters (houses in Chicago are pretty close together so it matters what my neighbors do in this regard). I'm obviously making efforts to correct that problem as well - changing the grade outside the house, hydrualic cement in chissled out cracks, Drylok paint, etc. Even if I do fix the water problems, I'm reluctant to put down a wood subfloor given this history. But I do like that idea.

If there was time and budget - the 'right thing to do' seems to tear out and repour the floor all together for the entire basement. It's just not in the cards right now. I may look into repouring just one section of the floor?

But, I think my plan at this point is to make it at least a little more even using some self-leveling concrete repair product and just learning to live with it not being level.

Thanks again for all your input.