How to Do a Fill-In on an Overlay

Clear away any loose dirt or debris from the section of overlay you need to fill with a wire brush. Clean the cleared area with a pH-neutral cleaner and a scrub brush to remove any oil or ground-in dirt. Rinse the surface with water then dry the overlay surface with clean rags.

Brush a layer of epoxy adhesive over the fill-in section to serve as a binding layer between the overlay surface and the new filler material. Allow the adhesive to dry slightly until it loses its wet look but is still sticky to the touch.

Mix a batch of self-leveling compound in a 5-gallon bucket, adding water to the compound until it’s pourable and mixing it with a wooden stirring stick.

Pour the self-leveling compound into the fill-in area, filling the space in 1/2-inch increments until the compound is even with the surface of the overlay. Use a trowel to smooth each layer, filling in any voids within the section and pressing out any air trapped under the compound.

Overlap the fill area slightly with the self-leveling compound and spread the compound over the edges with the trowel. Feather the sides lightly along the overlay surface, helping to create a seamless continuous surface between the overlay and patch.

Allow the self-leveling compound to dry, according to for the compound manufacturer's recommendations, before stepping onto the surface.