I remember hearing our house cracking during a minor earthquake, and if it hadn’t been for the groaning and snapping sounds coming from the walls and rafters, I might never have known the quake was happening. It turned out that almost insignificant shaking was a precursor to the catastrophic Loma Prieta Quake of 1989, which occurred several months later. By demolishing freeways, leveling buildings and destroying practically every chimney in the county, that event provided a tutorial on the vulnerability of man-made structures to earth movements.
If you hear your house cracking this summer, it probably doesn’t mean an earthquake is happening, but it could mean the ground is shifting for other reasons. Sudden changes in temperature can also cause cracking sounds. Most of the time, these sounds are nothing to worry about, but when you start seeing cracks as well as hearing them, it’s time to investigate. Your house could be at risk.
How Heat Impacts Building Materials
Building materials, including wood, steel, masonry and glass, expand when the temperature goes up and contract when it goes down again. Each material expands and contracts at a different rate, which is defined by its coefficient of thermal expansion (CoTE). You’ll find a list of CoTEs for different materials in a table provided by InspectAPedia.
In summer, materials expand during the heat of the day and contract at night, when it’s cooler. Temperature changes occur fairly quickly, and because materials respond at different rates, they push and pull against each other, creating groaning and cracking sounds in the process.
Why Your Attic May Be the Source
An attic gets very hot when the summer sun shines high in the sky. If it isn’t properly ventilated, the temperature in an attic can reach up to 160 degrees, according to Roofing Bros. When the sun goes down, the temperature drops quickly, and thermal snaps, crackles and pops result as materials contract. This is usually nothing to worry about, but it isn’t the only reason for house-cracking sounds originating in the attic.
When the wind blows, it actually lifts the roof, and as the rafters tug at the fasteners holding them, they can produce all kinds of groaning, squeaking and knocking sounds. There’s usually no reason for concern, unless the winds are strong enough to blow the roof off. In that case, you should probably evacuate or get down in the basement ASAP.
Soil and Foundation Issues
It’s comforting to think the ground is stable, but it’s hard to maintain that belief when you’ve been through an earthquake. In fact, soil is constantly shifting, aided by water draining, seasonal thermal effects and organic processes. These changes can undermine a building’s foundation, and cracking sounds can result as the building settles.
House-cracking sounds from foundation settling can come from the floor, walls, or roof, and they can be sudden and loud at times. If they recur or you see visible cracks in the interior drywall of the foundation, it’s time to call for a soil or foundation inspector to assess your repair options.
Shifting Doors and Windows
When you suspect house-cracking sounds are due to foundation settling, but you aren’t sure, check the operation of the doors and windows. Do you notice a door that constantly swings open or closed? Are any windows harder to open than they should be? Both of these confirm the diagnosis, because foundation settling throws window and door frames out of square.
Pipes and Plumbing
The cause of cracking sounds from plumbing pipes may be thermal expansion and contraction. Copper pipes carrying hot water tend to make cracking sounds, because copper expands when it’s heated and contracts when the surrounding air is cold. If your house has PEX pipes, it’s unlikely you’ll hear these sounds, because plastic isn’t rigid and doesn’t make noise.
Thumping and pounding sounds when you operate a faucet or flush a toilet don’t have anything to do with thermal expansion. They are usually caused by water hammer, and the remedies are to install a water hammer arrestor near the offending fixture, reduce the water pressure in the house or replace all your copper pipes with PEX.
Warning Signs You Should Not Ignore
When you hear your house cracking, the sounds could have a number of causes, including electrical issues, which haven’t yet been mentioned. The number one indication that you shouldn’t ignore them — apart from the sounds being so loud that it’s obvious something big is happening — is that you can see or smell damage.
For example, crackling and popping sounds caused by electrical arcing are often accompanied by smoke, blackening around the affected fixtures and the acrid smell of plastic burning. Pipes that constantly tap due to thermal expansion may start leaking, and when that happens, you’ll probably see wet drywall or water on the floor. If the sounds are due to structural issues, visible cracks appearing in the walls, ceilings or foundation, as well as sticking doors and windows, are warning you to do something now to hopefully forestall major repairs.
FAQ
Should I worry if my walls develop small cracks during the summer?
Hairline cracks are usually harmless, often signifying little more than plaster or drywall mud cracking due to thermal expansion. They become problematic when you notice they are widening or spreading.
When cracks occur along drywall seams or in corners between the walls and the floor or ceiling, or they radiate horizontally, in steps, or diagonally from the tops of door and window frames, it’s time to find out why. The cause could be something as simple as excessive vibrations from an air conditioner, but it could be something more serious, like soil settling or even a minor earthquake.
Is there anything I can do to reduce summer house noises?
If thermal expansion noise is bothering you, you can dampen it in several ways. You can seal gaps in the walls and around doors and windows with weatherstripping or acoustic caulk, add extra insulation to the walls and ceiling to absorb sound, place rugs or install new carpeting, or hang thick curtains. It may help to add soft sound-absorbing chairs and sofas to your home’s furnishings.
Sources
- InspectAPedia: Table of Coefficient of Expansion of Building Materials; (2026)
- The Roofing Bros: Why Is My Attic So Hot? Attic Temperature Chart and Solutions; (2026)
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