Cracked, heaved and sunken sidewalk flags are the most common reason New York City property owners call us. Left alone they become trip hazards, and under NYC Administrative Code the adjoining property owner is responsible for keeping the sidewalk in safe repair.
What sidewalk repair involves
We start by identifying which flags actually need attention. Where a flag is cracked through, lifted above its neighbour, or has sunk and now holds water, it is cut out and removed. The sub-base underneath is inspected, regraded and compacted, because a poorly prepared base is what causes a new flag to fail early. New concrete is then poured to the correct thickness, finished to match the surrounding walk, and jointed so it can move with the seasons without cracking.
Common causes we see in NYC
Street tree roots lifting flags from underneath, freeze and thaw cycles opening hairline cracks into full breaks, settlement over old utility trenches, and heavy delivery traffic on residential walks that were never built for it. Understanding the cause matters, because repairing a flag without addressing the base or the root zone means repeating the job in a few years.
Repair or full replacement?
Not every damaged walk needs a full replacement. If most of the flags are sound and the damage is localised, repairing the affected flags is faster and costs considerably less. If the walk is failing across its length, or the base has broken down, replacement gives a better long term result. We tell you which applies to your property before any work is quoted.
Where we provide this service
Concrete Sidewalk Repair is available across Manhattan, Brooklyn, Queens and The Bronx. Every borough files permits and fails differently, and the borough pages explain what that means for your block.