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.
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?
Best Answer
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.