My garage floor is not level. The garage doors are level as I have held a spirit level up to each. One side of the garage door gently touches the floor (as desired). The other side has a gap between the bottom of the garage door and the floor of 2 inches.

enter image description here

enter image description here

I have researched how to fix this and videos show that self levelling compound exists. From what I've understood, I use an adhesive such as Eco Prime Grip on the existing concrete, and pour the self levelling compound on top.

The confusion I have is, the levelling compound description on the website says

Coat Depth: 1-10mm

Does this mean that I can only apply up to 10mm at a time? Or can I use this to try to fill this 2 inch gap?

  • 2
    Are you saying the floor slopes sideways 3" in just 20feet? Have you measured with a plumb line to confirm the issue is not partially a crooked hanged garage door?
    – mark f
    Commented Sep 27, 2020 at 14:25
  • Hi @markf. I used a spirit level. I've also added more detail to give the real information. I omitted stuff to try and keep the question simple. It's a double garage door and is 2" (the 3" was a typo) Commented Sep 28, 2020 at 8:05
  • self leveling compound is quite expensive. but if you're made of money you can do it in layers.
    – Jasen
    Commented Sep 28, 2020 at 8:26
  • Related diy.stackexchange.com/q/194492/46271. Modify bottom edge of door or grind out some concrete on the high side where door bottom hits
    – Kris
    Commented Sep 28, 2020 at 18:29

1 Answer 1


Yes, you can only use such products to a certain depth. This is due to shrinkage and lack of aggregate, which means that thicker applications become rather weak.

More importantly, though, is that those products are not intended as a finished flooring surface. They're soft and chalky when cured, and you're supposed to put actual flooring over the top. It will not withstand the rigors of garage life.

Secondly, your garage slab may have been intentionally poured with a drainage slope. This means you can't use self-leveling products without causing a puddling problem. If you're in a freezing climate this is a serious concern.

You'll need to pour a new actual concrete slab--either as a replacement or over the existing in a substantial thickness.

However, if your only goal is a sealed door opening, I'd install a tapered shim onto your door and a new astragal (seal). Much cheaper and just as effective.

  • You'll need to pour a new actual concrete slab--either as a replacement or over the existing in a substantial thickness. Can I assume I would simply clean the existing flooring, a frame around the area I want to 'level', put down a layer of adhesive within the frame and then add and screed the new concrete layer (sounds simple when it's written like this!!) Commented Oct 30, 2020 at 11:25

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.