Why Does Sheet Metal Make Noise

The noises are usually caused when the thin sheet metal of the ductwork expands to accommodate the sudden change in pressure caused by the airflow.

Why does sheet metal make noise. Following are common duct noises and what may be causing the problem. Duct sheet metal may cause all sorts of noises from one or several different reasons. Rattling noises are often the result of loose metal ducts knocking against each other. A sudden wind gust knocked me down and the plywood sheet went sailing out of my hands.

Installing a metal roof over a solid deck with a good underlayment like double bubble and with an insulated attic airspace below makes it easy to control the noise. As ducts age the sealing fails and duct connections wiggle loose from the static pressure. The lower the gauge rating the thicker and stronger the metal. This is a step that must be taken during the installation process.

Installing an underlayment between the metal roofing and the roof sheathing is a key step to reducing metal roof noise. While all hvac systems make some noise when they are on when there is excessive noise such as popping knocking and banging it can indicate a problem. If every time you turn on the heating or cooling system the air ducts start popping and banging read the rest of this article for tips on how to reduce and even stop the noise entirely. However if you take a sheet of metal which isn t tightly stretched and wham it it starts to wobble freely.

Years ago as a young builder i almost got blown off a roof while trying to carry a sheet of 4 by 8 plywood. Generally the noises occur after the hvac system comes on and the conditioned air begins rushing through the ductwork on its way to being delivered in your home. Amplified within the thin sheet metal enclosure of the ductwork this noise usually seems louder than it actually is. To relieve this stress the sheet metal buckles slightly outward making a booming or banging sound.

A thick and strong metal can withstand more pressure therefore making it less likely to expand which reduces the popping noises. When following these tips some say their metal roof is even quieter than their old shingle roof. Most home ductwork uses a 24 26 gauge sheet metal which is a sweet spot.