If you notice humps, bumps, ridges or bulges in your basement floor, these could be signs of serious damage beneath the surface. The cause of the damage can vary based on the type of basement you have and what floor material you use. Some causes have easy fixes, such as replacing certain parts of the flooring. Other causes indicate much more serious problems that may require remodeling to fix.
Moisture is the enemy of all basement floors. Because a basement exists below ground level, it tends to collect moisture more easily than other floors in the house. If you have a wood floor installed in the basement, moisture could be causing the wood to swell and create humps. Typical hardwoods should not be used in basements. Manufactured wood with synthetic cores are more suitable for these applications, since they can resist moisture problems more easily.
If you have laminate or vinyl floors, the problem may be more connected with installation. Not all plastic floors are made for basement use, but even those that can be used in basements need to be installed with expansion gaps along the walls. These gaps allow the floor boards to expand or contract along with temperature changes. Without these gaps, the boards will start to push against each other and form ridges.
Problems in the concrete will not go away if you try to cover them up. Carpet, wood, and vinyl will all relay concrete problems upward. This means if you have bumps in your concrete before installation, the bumps will eventually transition into your new floor, causing new versions of the same problem. Sanders and fillers can help level out concrete floors before installation to fix this problem.
If your concrete is actually cracked or is pushing up against the floor when there was no previous problem with installation, this could indicate a much more serious problem connected with your foundations. Foundations are subject to a variety of pressures from outside soil and water. Large humps can indicate a failed foundation that requires immediate remodeling to place additional supports and fix the problem.