• Garage floor is cement
  • 24'x32' (except where the car will park.)
  • far side is approximately 6"lower than the other. (~1° slope)
  • large crack running the full length.
  • a number of smaller cracks.
  • some old oil stains.

What I've got so far:

  1. Power wash the floor of the garage.
  2. Scrub and remove oil stains. (What do I use?)
  3. Let fully dry. (How long?)
  4. Use angle grinder with concrete cutting wheel to clean up and widened crack.
    Update: Recommended to use a concrete saw instead.
  5. Fill crack. (Bondo All Purpose Putty?)
  6. Update: Use a Bonding Agent between the layers. (Something like Latex Drylok Bonding Agent?)
  7. Use something between 2x4 studs/base plate to separate the cement and the wood and keep the cement from filling the stud bay. (Flashing maybe?)
  8. Caulk cracks at base plate. (Silicone?)
  9. Build Walls and seal gaps. (Silicone?)
  10. Mix and pour cement. (What cement should I use keeping cost and simplicity in mind?)
  11. Tool the cement so it's level.


  • planning to use epoxy coating for floor.
  • prefer to use something that is simple but cost effective. (If you can call any of this simple)
  • will not pour where car is going to park.
  • will be both a workshop and a garage.


  • Am I missing any steps?
  • What are good products to use given the depth of the pour goes from 0" to 6"?
  • 2
    Does the garage floor slope to promote drainage or is it totally a nuisance? Generally, you want some slope to a garage floor so if you park your car inside after a rain/snow, water runs out toward the door opening. For cleaning up a crack dozens of feet long, consider renting a concrete saw or buy a 7-inch dry concrete saw blade for your circular saw. It will be a lot easier than using an angle grinder. Dec 5, 2020 at 11:05
  • Concrete doesn’t just crack for no reason - something caused it to crack and it’s likely to get worse unless you find out why/fix it. Dec 5, 2020 at 11:08
  • Regarding levelling out the slab - you can’t make concrete “zero inches” thin - it needs steel and small rocks for strength and generally 150mm (6”) thick for a small car or 200mm (8”) for a large car or two small cars. Usually a slab has gravel under it - concrete on top of concrete needs some kind of bonding layer between the two. You’ve asked for something simple, but I don’t think this is a simple project. Dec 5, 2020 at 11:13
  • My guess is that it slopes for drainage, However, I only need the slope for the part where the car sits. I'm not planning to level the cement where the car sits, just where the shop tools and tables will go. Good call with the concrete saw.
    – ScrappyDev
    Dec 8, 2020 at 3:49
  • @AbhiBeckert - I've heard of a process that can be used to reinforce the foundation, but not really sure who to contact for that. Other options would also be appreciated.
    – ScrappyDev
    Dec 8, 2020 at 3:56

1 Answer 1


I’ve used Gypcrete over concrete slabs and various wood structures.

I think it’s rated up to 8” thick per lift. However, it can’t be walked on, etc. because it will wear. You’ll need provide a covering.

It goes in like tomato soup, so it will seek its natural level. It hardens in a couple of days.

  • Would an epoxy coat count for a covering, or is it so loose that it would just flake off. Most of the photos I see for it seem to be for underpayment and heated floors.
    – ScrappyDev
    Dec 12, 2020 at 1:38
  • 1
    I don’t think an epoxy coating would last.
    – Lee Sam
    Dec 12, 2020 at 2:04
  • Thanks, I'll keep researching.
    – ScrappyDev
    Dec 16, 2020 at 3:12

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