Repairing Concrete: Window Sills Exterior [upd]
Apply an epoxy adhesive to the chipped area and reshape it using a trowel to match the original profile. 3. Addressing Major Damage (Resurfacing)
While DIY is great for surface repairs, call a masonry professional if: repairing concrete window sills exterior
Before beginning, gather the following:
If the damage is widespread but the sill is still structurally sound, resurfacing is the best option: How To Repair a Damaged Sill, Step By Step Apply an epoxy adhesive to the chipped area