Window Sill Repair Concrete <UPDATED>

Screed the surface flush with the original plane. Create a slight negative slope (approx. 5°) away from the window using a straightedge. Texture to match existing concrete (e.g., broom finish or smooth steel trowel). Cure for a minimum of 7 days using wet burlap, curing compound, or plastic sheeting. Premature drying causes micro-cracking and bond failure.

Concrete deterioration on sills is primarily physical and chemical. According to the Portland Cement Association (PCA), the most aggressive agent is chloride-induced corrosion of embedded steel reinforcement. When rebar corrodes, iron oxide occupies 2–4 times the volume of the original steel, generating tensile hoop stresses that exceed concrete’s low tensile strength (Mehta & Monteiro, 2014). window sill repair concrete