If you’ve has some type of water damage or insect infestation, you may find that you have damaged subflooring in the home. Sub-flooring is just what the term sounds like: material underneath the surface you walk on. It may be concrete, or plywood, or several other types of material. Unfortunately, even the most robust sub-floor material can become cracked or mildewed. Water can become trapped between the floor and the sub-floor or between the top surface and the sub-floor. Those and many other types of problems will often require making repairs.