We just moved into our new house about 5 weeks ago. In the basement the floor has several small cracks on one side of the house. One of them is getting a little bigger. We have a sump pump in the basement and the basement does not leak. Are these cracks normal or is there some problem that I should be concerned about?
Your concrete floor is probably fine.
Hundreds of gallons of water leave your floor concrete over the first year and this causes shrinkage. This shrinkage commonly shows as a fine crack, which is typically an even width along the crack. Some builders design shrinkage joints or control joints in basement floors which show up as a relatively “straight” crack in a concrete floor. This concrete shrinking can also show up as a small crack next to the foundation wall all around the perimeter of the house.
Your basement floor crack is not likely a problem unless the crack becomes uneven or shows signs of mis-alignment from one side of the concrete to the other side of the crack. Caulking this crack or cracks is wise to control radon gas and keep it out of the basement.
Simply caulking the cracks are wise. I suggest you have your house and your basement tested for radon gas and have it abated. The correction is relatively simple and fairly economical compared the risks of lung cancer.