Some concrete floors, especially smaller residential applications, are one solid piece, but larger floors are often poured in pieces. This allows the floor to move with differences in temperature and requires joints.
What do joint sealers do?Joint sealers are used to seal and caulk both moving and non-moving joints and cracks. These are made of high-performance, catalyzed polyurethane sealant and can be used both indoors and out.
Why fill the cracks?Joint fillers stabilize the edges of the concrete slabs and help reduce wear from traffic. The edges of the slabs are liable to crumble over time and the filler reduces this. Filling joints also prevents water from getting between the slabs of concrete. If water gets in and then freezes, this can cause the concrete to raise up or crack.