Concrete joint sealing and crack filling
Every open joint is a funnel. Sealing them is the cheapest way to make a lifted slab, or a new one, stay put.
Driveways, walks and patios are divided into sections by control joints, and there's always a joint where flatwork meets the house. Those joints, plus any cracks that open up over time, let water reach the soil under the slab. In Rochester, that water freezes and thaws dozens of times a winter and runs hard during spring melt, loosening and carrying off the base. Flexible joint sealant closes those paths.
Where sealing pays off most
- The joint between a stoop, patio or driveway and the foundation
- Control joints across driveways and garage aprons
- Cracks that opened after a slab shifted
- Drill holes and joints right after a leveling job
What sealant won't do
It won't raise a slab that has already dropped, and it won't stop the surface flaking that deicing salt causes. Think of it as maintenance: it protects the base so leveling, or a brand-new pour, lasts longer.
How often should joints be resealed?
Sealant ages from sun, traffic, plowing and constant slab movement. Walk your concrete each spring once the snow is gone and look for sealant that has split, pulled away or gone missing. Late spring through early fall, when slabs are clean and dry, is the usual window for resealing.
Backer rod and proper depth
Wide joints are usually packed with a foam backer rod first so the sealant sits at the right depth and can stretch as the slab moves. Skipping this step is a common reason do-it-yourself sealant fails after one season.
We don't publish prices. The contractor sets the price after measuring the slab, sounding out the void underneath and finding out why it dropped, so treat any figure you hear before that visit as a ballpark.
Where we connect you with help
Common questions
Can I seal joints myself?
Small, narrow joints are a reasonable weekend job with self-leveling sealant and backer rod. Long runs, wide gaps and joints following a leveling job are often worth having a contractor handle.
Does sealing help in winter?
Sealant has to go on in mild, dry weather, but its value shows up in winter and spring, when it keeps meltwater from getting under the slab.
Related services
- Foam lifting and mudjacking
- Driveway and garage floor leveling
- Sidewalks, walkways and patios
- Steps and stoops
More background: Rochester concrete leveling guide.
Is a slab tipping, dropping or holding water?
Call and a Rochester-area concrete lifting contractor will come look and tell you whether it can be raised.