What Are the Causes of a Popping Sound in the Wall & Attic?

Settling

• Settling occurs as your house ages. Over time, the ground under your home can shift slightly, causing your foundation and framing to also shift slightly. As pipes, joists and joints shift their position, they may make a popping noise. Settling is normal, and the popping noises may continue for the life of your house. However, if the popping noises are accompanied by the appearance of cracks in your walls, it may mean the ground has shifted a great deal and you have subsidence. In this case, you should contact a structural engineer for advice.

Expansion and Contraction

• Many of the materials used in the construction of a house, such as concrete and wood framing, may expand or contract slightly with changes in temperature. If this is the case, you may hear popping sounds more often when the weather is very cold or very hot. The popping may be caused when wood held in place by nails expands to the point where it suddenly releases pressure. This will make a loud popping or banging. It is usually harmless, unless it is also accompanied by cracks in the walls.

Pipes and Ducts

• Quieter pops can be caused by expansion or contraction in pipes or ductwork, especially on very hot or very cold days. If your pipes have frozen with water in them during a cold snap, popping sounds could signal the ice in the pipes defrosting. If your pipes have frozen, you will need to check them for leaks once they begin to defrost, as the expansion of ice in the pipes can cause them to crack and rupture. Very hot water moving through PVC pipes can sometimes causes these pipes to expand slightly and rub against nearby pipes or wooden joists with a popping noise. Louder popping sounds can also be caused when the blower fan in your furnace pushes metal ductwork out. When the fan shuts off, the ductwork will move back into position, again making a loud popping noise.

Pests

• Every home has pests of some kind, and these can cause popping noises as they chew or scratch in your walls. Popping noises can also indicate that wood-eating insects, such as termites, have weakened the structure of your house, causing beams or supports to shift and make popping sounds. This type of problem needs to be checked out by a trained pest controller or exterminator, as pests can damage your home or result in a health hazard.