Leveling the slab

[Tom Bender]

How about some advise on leveling the floor of an existing garage shop.

The floor slopes down about 1 1/2" for slush drainage. I want to eliminate that so it is flat enough for mobile machines. I will bring in a car and will just deal with any water, probably by parking outside on those days.

The floor has 2 expansion joints with 1/2" isolation board. The shrinkage cracks are not moving or spalling but there is some spalling to fill.

The surface is not slippery when wet or dusty and needs to be that way when finished. Want to top with epoxy.

The floor has to survive freezing temps so SoCal solutions may not work.

[Jim Becker]

What you have to be careful of here is how a garage would be treated upon resale if you did this leveling and it was permanent. If you dedicated the space to woodworking and put in a leveled wood floor..."fun" because of all the tapered furring that would be required...it could easily be removed in the future. If permanent is the choice, there are pourable products that can be utilized. They may or may not need to be done in steps, depending on acceptable one coat thickness for curing.

[Frank Pratt]

You don't need level for mobile machines. My floor slopes 3" over about 24' & about the only time I notice it is when my table saw wants to roll down hill toward the door. I just don't let go of it while moving. The mobile drill press, jointer, workbench and planer/sander flip cart don't have that issue.

[Jim Becker]

Frank, that's true, level isn't required, but you do have to choose up-hill or across hill orientation when using them for best results just as that's true for fully stationary machines. My shop building was constructed as a garage by the previous owners and I have had to deal with this for a long time now. Some kinds of tools demand level for best results...my slider and my CNC are examples. The other challenge is the work bench...mine is mobile capable, but I have to keep one end blocked up for it to be level, so it rarely gets moved. In hindsight, I should have asked the same question that Tom asks years ago and done something about it...and I will say that it's a factor for whatever my next shop is as we move through the downsizing process.

[David Walser]

Tom -- You have lots of options. A few years ago, we enclosed a covered patio to expand our kitchen and dining area. The patio floor was sloped and it was about 4" lower than the kitchen floor where the door opened onto the patio. Also, the patio floor had several expansion joints that we did not want in the floor of our new room. To address all these issues, a new concrete floor was poured on top of the patio. It had additional steel in it to help reduce cracking. (It's been over 10 years and there is no cracking, so far.) We finished the floor acid staining to match the rest of the kitchen. You could do something similar with your garage floor. If you went this route, I'd suggest installing a floor drain and, perhaps, heating the floor. The downsides are this would reduce ceiling height, would create a small curb at the entrance to the shop, and would be expensive.

Another option would be to level the floor with one of the pourable self-leveling products available for this purpose. Again, this would create a small curb at the door opening, but it would be smaller than the one created in the approach described above. Again, I would suggest installing a floor drain and, possibly, radiant heating. It's not as expensive and the ceiling height loss would not be noticeable. Depending on your heating needs, this may be your best option.

Or, as others have suggested, ignore the gentle slope of the floor. 1.5" over the length of the typical garage isn't much. With the possible exception of a lathe (where the bed needs to be level to avoid vibrations and to ensure alignment of the head and tail stocks), your equipment should work just fine with that kind of slope. But, no radiant heat! (Oh, my!)

[Frank Pratt]

Frank, that's true, level isn't required, but you do have to choose up-hill or across hill orientation when using them for best results just as that's true for fully stationary machines. My shop building was constructed as a garage by the previous owners and I have had to deal with this for a long time now. Some kinds of tools demand level for best results...my slider and my CNC are examples. The other challenge is the work bench...mine is mobile capable, but I have to keep one end blocked up for it to be level, so it rarely gets moved. In hindsight, I should have asked the same question that Tom asks years ago and done something about it...and I will say that it's a factor for whatever my next shop is as we move through the downsizing process.

Ya, I can see that a slider or CNC would want to be level.

[Bill Dufour]

What will you do with the 1+1/2 " step at the entrance? Leave it at 90 degree and it is a trip hazard and makes running anything in and out a bit troublesome. Fill it with a angle ripped 2x4? Make a short ramp and car drivers will complain why is it not a smooth gradual transition.
Bil lD

[Lee Schierer]

You can mount a push - pull toggle clamp to raise the down hill end and lock the equipment in place. I have a pair of these on one end of may mobile jointer to prevent it from moving during use.

pp-302f-push-pull-toggle-clamp-cross-referenced-605-18.gif

Some models will lift 800 pounds each.

[Wes Grass]

The slope is only slightly annoying in mine. Creates an auto retract on the slider if its lined up that way.

What annoys me a lot more is that it's not even remotely flat. If I move anything, it's going to rock, and I have to tweak the feet or find a shim of some sort.

[Ryan Yeaglin]

my basement slopes for a floor drain, I used the levelers on the table saw to level it. Carts or stands can be had with locking casters so they don't move. 1.5" over 24' or so isn't much at all.

[John Goodin]

My garage has a similar slope and the biggest issue is an outfeed table on the table saw. Eventually I will buy an outfeed table that attaches to back of the saw and the problem will be solved. I also have placed a 1.75 inch concrete cap on a roughed up slab that was our dining room. A high strength concrete was used and it lasted at least until we sold the house several years later. Keep in mind my wife never let keep my table saw in there.

[Jack Llewyllson]

What you have to be careful of here is how a garage would be treated upon resale if you did this leveling and it was permanent.

Although it probably marks me as a person of dubious character, I don't guess I would worry too much about that. If someone buys this property and wants the shop ("detached garage") floor to drain rather than be level, they can address it at that time. Just as we've had to address water running downgrade into the attached garage (French drain FTW) and Dog knows how many other issues since buying this house.

Used houses are like used cars, only with better resale value. They come with issues, and part of the challenge is sorting those out.

It's your shop. If you want your shop floor level, I'd recommend that you pour a self-leveling product that makes you happy, and call it good. Someone can always come in and gypcrete over it to recover some slope, or just demo out whatever you laid down.

[Jim Becker]

Jack, I was referring more to inspections upon sale, etc. There probably wouldn't be an issue in many places, but woah to you if you happen to be in "that place" where it got flagged. I may be in a situation where a new shop building may come into the picture if the stars align and it's going to be interesting to see if the jurisdiction will permit the building, which necessarily would be referred to as an "Accessory Garage Building" for permitting purposes, to have a level floor or not. I sure hope so if that comes to pass, but will deal with it if otherwise...probably by just living with it and parking equipment like I have in my current shop. The expense of adding a leveled floating wood floor over it would likely be more than I'll be willing to invest. It would already be smaller than I'd prefer, but thems the breaks...

[Charles Lent]

If it has A GARAGE DOOR, I believe the building codes require that the floor be sloped toward the door for drainage and to reduce "heavier than air" vapor build up in the space.

My shop has a floor that is sloped in several directions (old building) by as much as 2". I have had no problems using my machinery and workbenches even though they sit at angles. I can check to see that my projects are square, but not using a level. I can set my table saw to cut at desired angles (to the saw table) and get good results. If I want to get the 4 legs of a chair or table not to wobble, I place them on a flat bench surface and then trim the longer leg to eliminate the wobble. My shop floor has never been a real problem for me.

Charley

[Bob Riefer]

If it has A GARAGE DOOR, I believe the building codes require that the floor be sloped toward the door for drainage and to reduce "heavier than air" vapor build up in the space.

Perhaps a regional thing? I was involved in the process to build many garages and even a fire station in the PA/NJ/MD/DE/NY area, and not a single one of them had any code requirements against flat floors. We advised most customers that flat floors were preferable unless they wash vehicles in the garage, or have enormous amounts of consistent snow melt considerations. About 90% of builds were flat floors.

In fact, floor drains were the bigger sticking point... not allowed on many of those builds.