What If I Caulk the Lines in the Cement of the Basement?

Curing Phase

• The curing phase of concrete includes shrinking of the material, as the nature of cement as it cures over time is to soak up the water in the mixture and harden into a slightly smaller state. Concrete expands roughly 2/3 inch for every 100 linear feet of concrete, which means the cracks can range from hairlines up to the aforementioned measurement, depending on the size of your slab.

Seasonal Movement

• All cement slabs in basements are subject to the expansion and contraction of materials during the freeze/thaw cycles of the year. This natural expansion of the slab will cause hairline fractures to occur. While you can caulk them if you choose, they will continue to grow over a period of five to 10 years while the house settles and the concrete reaches its comfortable phase.

Expansion Joints

• Expansion joints are cuts or purposefully installed joints or lines that cut through a cement slab to help guard against hairline fractures from seasonal movement and to help with the shrinkage during the curing phase. Most expansion joints are 1/4 inch wide and are placed periodically throughout the slab to force the concrete to use those lines for movement rather than fracturing hairlines over time.

Nature of Caulk

• Caulk is primarily designed to work as an adhesive and filler for corners or areas that need to be protected from movement and water, as well as from dirt and debris. While you can caulk the lines in basement cement, it is an entirely optional process. The slab is going to crack over time no matter what you do to it, so caulking the cracks will be an ongoing process.