Resurfacing over a bad slab
An overlay is a surface. It bonds to what is underneath and it inherits everything that is wrong with it. Put one over a slab that is settling and the new surface cracks along the same line within a season, because the movement causing the crack has not gone anywhere. Put one over a slab with a failed base and it will spall off in sheets the first time water gets under the bond. That is the expensive mistake in this category, and it is expensive twice — you pay for the overlay, then you pay for the demolition and replacement you were trying to avoid, now with an extra layer to remove.



