Advice on how to level slab

[asciutto]

Hello!

I'm new to the forum having discovered it through various searches about leveling a garage slab. What a wealth of knowledge here!

The previous homeowner built this garage about 10 years ago and the attention to detail on the slab was not great. Finish is poor and there are significant low spots throughout. I'm not looking for epoxy smooth but smooth enough to roll cabinets and some woodworking equipment on caters without getting snagged.

My plan is to finish the space (insulation / plywood walls) and put in a split unit. Fixing the pad will fit somewhere in there!

e:
I should have included this information from the beginning.

• Space is 25' deep x 3' wide.
• 4" thick pad, with 6" thick for a 4-post lift on the man door side.
• Dual-purpose. Car parking in the 2-bay area and workshop on the other side.

This picture is about 5 years old but its the best one I could find showing the condition of the slab. The amount of stuff has grown... substantially in recent years.


Shot from behind showing the uneven pour where the garage door is:


I'm not against getting a cap poured if that is the most cost effective solution but I'm hoping there might be another way. Everything I've read indicates you want at minimum 2" which means the door would have to be raised up so I'm redoing the header and now the scope has grown more significantly than just hiring a concrete contractor.

Would this be a good candidate for using the quikrete re-cap or the ARDEX concrete restoration system?

Please help educate me! I'm sure my ignorance is showing here

 

[Rusted Nut]

Sounds like you could use a self leveling cementitious compound. I’d recommend CTS Rapid Set Self Leveling. It cures to 5000 psi. I think it goes to 2”. Good product. Follow prep directions closely, chip off anything that is loose.

 

[ConCretin]

I'd be tempted to make a saw cut behind the overhead door and remove an inch or so of concrete to create a level strip for the overhead door to land. This would result in a better seal under the door and the shelf would keep water from coming under the door and onto the floor.

 

[asciutto]

I'd be tempted to make a saw cut behind the overhead door and remove an inch or so of concrete to create a level strip for the overhead door to land. This would result in a better seal under the door and the shelf would keep water from coming under the door and onto the floor.

I like that idea!

Would you recommend doing that first and then using the lip as the edge for a short form to set the height for the self-leveling compound that Rusted Nut suggested?

 

[asciutto]

Sounds like you could use a self leveling cementitious compound. I’d recommend CTS Rapid Set Self Leveling. It cures to 5000 psi. I think it goes to 2”. Good product. Follow prep directions closely, chip off anything that is loose.

I looked into this product and the only one I can find is the "Rapid Set Concrete Leveler® Quick-Setting, Self-Leveling Floor Underlayment". Is that what you are referring to? If so, the instructions it says it should not be used as the finished floor surface. My intention is to park our cars back in the garage as well.

 

[Built To Work]

watching this thread, as I too, have the same issues.

 

[duneslider]

self-levelers are not designed to be the final floor, you would need to put something like epoxy over it. The surface of the self leveler just doesn't get really hard like concrete and shouldn't be the wear surface, it will wear down with traffic. For something this big I wouldn't want to try and do it myself either. Probably worth hiring it to a company that does it and has a crew and big mixer truck/trailer for it.

 

[asciutto]

self-levelers are not designed to be the final floor, you would need to put something like epoxy over it. The surface of the self leveler just doesn't get really hard like concrete and shouldn't be the wear surface, it will wear down with traffic. For something this big I wouldn't want to try and do it myself either. Probably worth hiring it to a company that does it and has a crew and big mixer truck/trailer for it.

Thanks! I was definitely planning on subbing this out. It is well beyond my comfort zone.

I hate to ask the question like this, but having to do a second layer of something different over a self-leveler was not what I anticipated. What would the least expensive 'final floor' option be?

It seems like doing DIY epoxy can be reasonably cost-effective, especially depending on the state of the existing floor. With a fresh layer of self-leveler being applied will there be much surface prep necessary?

 

[duneslider]

I'm not an epoxy expert but I would think a fresh layer of self-leveler would not need anything else. If you aren't trying to change the color you could probably just do a clear on top and not do anything else. You would want to check with one of the vendors on here for proper procedure for a coating over self-leveler. I would think a clear polysporatic would be a good option though.

 

[Rusted Nut]

I looked into this product and the only one I can find is the "Rapid Set Concrete Leveler® Quick-Setting, Self-Leveling Floor Underlayment". Is that what you are referring to? If so, the instructions it says it should not be used as the finished floor surface. My intention is to park our cars back in the garage as well.

Check out this product:

TRU® SELF-LEVELING Datasheet | CTS Cement

www.ctscement.com

We used this in a maintenance shop, turned out well.

 

[geneg]

Ardex makes some of the best self levelling products that I know of. Used their products on industrial projects.

Levels to a feather edge, extremely hard, & can be left uncoated. Absolutely not cheap, but you'll only have to do it once. Follow all of the prep instructions. Either divide the area into smaller segments with edge forms, or do the entire at once. Just maake sure you have enough material available to cover everything & have one person mixing while a couple others pour & spread.

 

[Sumboodie]

self-levelers are not designed to be the final floor, you would need to put something like epoxy over it. The surface of the self leveler just doesn't get really hard like concrete and shouldn't be the wear surface, it will wear down with traffic. For something this big I wouldn't want to try and do it myself either. Probably worth hiring it to a company that does it and has a crew and big mixer truck/trailer for it.

Definitely are self leveling products that are better than concrete for wear and strength.

I've seen it used to renew worn floors in industrial settings.

 

[duneslider]

Most self levelers I have worked with they suggest a sealer over them. Even all the concrete in warehouses and industrial buildings get a sealer of some sort even if just to help prevent dusting. I have never seen someone put a leveler down and not at least put something on it to prevent dusting. I am sure there are people that do but I just haven't seen it done.

 

[BillK]

What is the space going to be used for ? Any car parking or just workshop ?

 

[asciutto]

What is the space going to be used for ? Any car parking or just workshop ?

I should have included that in the OP!

Car parking and workshop to the side.

Dimensions are 25' deep, 30' wide. 4" thick pad with four spots at 6" for a 4-post lift.

 

[BillK]

I know a lot of guys don't like it but I would consider Commercial Vinyl Tile. I had it in most of the first building I had my business in and actually held up very good in a machine shop environment. I think it might be a little more forgiving of a not so perfect surface. You will still have to do something with the area where the door sits but its just another option. A lot of it depends on installation costs in your area.

Here are some examples:

VCT Tile - Vinyl Flooring - The Home Depot

Get free shipping on qualified VCT Tile products or Buy Online Pick Up in Store today in the Flooring Department.

www.homedepot.com

 

[Dig Doug]

Get some good knee pads and a 6 ft level and a pencil and a pencil sharpener

run that level around looking for low points mark it up w/ pencil
Then I think I would saw cut and remove & replace it
dowel into existing concrete all around

25ft X4Ft X 4 inch is 1 1/4 yard of concrete

it’s a lot of work to remove but you’ll get a better end product

 

[flyingblind]

Fix the stuff around the doors and clean it real well. Mortar and Tile it.

 

[ConCretin]

Self leveling products sound a lot easier and foolproof then they are. Proper surface prep is labor intensive and product application isn't realistically a DIY operation for most. I'd just address the condition at the overhead door and do some selective grinding to smooth things out. I doubt you'll even notice the defects once you start using the space.

 

[Built To Work]

I doubt you'll even notice the defects once you start using the space.

Words of wisdom for me. I will just get bigger caster wheels and call it a day. Not motivated enough to cut out concrete and re-pour. Not skilled enough to properly prep, level and tile the floor.

 

[Armorpoxy]

Many of the self levelers like Ardex and Rapid Set make versions that can be coated. An ideal/inexpensive protection could be our Coval spray on sealing system. More impervious to oils and fluids and super easy to apply with almost no prep.

 

[Busted Knucles]

Rent a concrete grinder and get your hose out and grind the surface flat then epoxy coat it. Did mine like that years ago and still looks the same as it did when i finished it. I ground my 2 car garage in one day.

 

[asciutto]

Thanks all for the suggestions! The pictures don't quite capture the unevenness of the floor. It has high and low spots up to 2" in difference.

I had a concrete company out to look it over. Plan is to demo out the driveway leading up to the garage door so that is level, saw cut expansion joints into the current floor, then pour a 2" cap.

 

[ColorMeOrange]

+ 1 for self levelling concrete. I helped someone do an extra large forya entrance with it. There was a dark slate tile border already in place it worked out real good.

It never even dawned on me to use it for one of the two interior rooms I'm 1/3 into right now. For the smaller adjacent mud room with side entrance. I like this idea the very best atm. I have to investigate it further.

It looks like most if not all of a form is already in place there. But isn't it a no-no to rest un-treated sill plate right on the exposed concrete how it looks like they did? Due to potential of rot over long term.

Pardon my post if its a very dry climate and earth under it all and that doesn't apply.

Nice big open canvass to work with over there btw