What Causes Creaking Floors?

Nails

• One of the most common causes of creaking or squeaking floors is loose nails, which results in the flooring board moving up and down under the weight of people walking on it. The creaking sound comes from the nail moving in and out of its hole. Sometimes floors start creaking as nails start to loosen due to age. Olders houses often make more noise than newer homes since the passage of time has allowed nails to become less secure.

Shrinking

• The shrinking of wood over time can also lead to noise in flooring. Wood often shrinks as its ages and this creates gaps between the floor boards, leading to more movement when the floor boards are subjected to foot traffic. Shrinkage typically results from dry conditions, so drafty homes that have a lot circulating air to dry out the wood might have noisier floors than other houses.

Sub-Flooring and Ductwork

• Creaks can also result from sub-flooring that does not attach to the floor joist properly. The loose connection of the sub-flooring, often a layer or two of plywood, allows the floorboard to move when someone walks across it, resulting in a creak. Another cause is ductwork that was not properly installed during the home's construction. The pressure caused by foot traffic can result in the ductwork squeaking, creaking or even making a popping sound.

Bridging

• Bridging involves placing wooden boards between floor joists to give the joists additional stength. Carpenters often install the bridging in an X pattern. The bridging members should not contact each other; at least 1/2 inch should separate the individual boards. However, if an improper installation occurs and the boards do rub up against each other, they could make a noise when pressure, such as someone walking on the floor, causes them to move.