When concrete slabs on grade curl, the curling sometimes has little effect on floor performance. If the total curl is less than 1/4 inch or curling occurs primarily in low-traffic areas or under storage racks, the owner can often live with it, provided that cracking isn't excessive. There are occasions, however, when curling isn't tolerable and repairs are needed. When choosing from the several repair methods available, contractors, engineers, and owners must evaluate the feasibility, cost, benefits, and limitations of each. These methods include:
- Wetting the top of the slab
- Cutting more joints
- Grinding the slab
- Removing and replacing part of the concrete
- Grouting underslab voids and grinding the concrete
- Adding dowel bars
Though many of these repair methods can be successful, they can also be costly, especially if they're done too soon and curling continues. Before implementing a repair scheme, determine how much curling has occurred and if it's continuing. A slab can continue to curl for months. Measuring weekly with a rod and level can help pinpoint slab curl locations and rates.