Nobody likes hearing their neighbors' music, TV shows or loud conversations. Soundproof wall materials, however, can be quite thick and expensive. Swedish scientists have developed a thinner, less costly alternative, in the form of a spring-loaded sound-damping screw.
Known as the Revolutionary Sound Absorbing Screw (or the Sound Screw for short), the device was created by a team at Malmö University, led by senior lecturer Håkan Wernersson. It consists of a threaded section at the bottom, a coil spring in the middle, and a section with a flat head at the top.
The screw is inserted into a hole drilled through a drywall panel and into the underlying wooden stud. It is then turned until its threaded section is all the way into the woodj, and its head is sitting flush against the outside surface of the drywall. The spring forms of a gap of a few millimeters between the stud and the drywall's underside.
When sound waves from an adjacent dwelling subsequently travel through the wooden stud and into a wall's Sound Screws, the compliant springs in the screws limit the transmission of the vibrations into the drywall. As a result, people in the room hear less of the noise.
In lab tests involving traditional drywall panels, it is claimed that Sound Screws reduced through-the-wall sound levels by 9 decibels, which worked out to about half the perceived sound when traditional screws were used. The technology also performed well when trialled on the ceiling of a hair salon, where the existing standard screws were simply replaced with Sound Screws.
Wernersson tells us that the screws are already available in Sweden (via spinoff company Akoustos), and that his team is interested in licensing the technology to a commercial partner in North America.
"The initial price is quite high for a screw, but cheap for a sound insulation system," he says. "The cost will decrease with volume."
Sources: Malmö University, Akoustos
The sound screw is designed for timber walls, not floors. The word joist/s implies it can be applied to floors. I'd suggest the words joist/s are substituted with stud/s , timber wall framing etc, as joist/s are used for the structural members for ceiling and floors. Eg; floor joists, ceiling joists. My TAFE teacher would say, wood is in the trees & timber is the structural material we use as carpenters. So maybe substitute wooden & wood with timber. See timber framing components https://www.yourhome.gov.au/materials/lightweight-framing. An alternative design screw pitch suitable for steel studs would also be good, as we use timber & steel studs in Australia
And @ Chuck... I can't see why they couldn't be used on plasterboard ceilings...?
Its like inventing a square wheel!
The existing solution, is foamed Polyurethane. Just a series of squirts onto a board, or the supports, and the board, can then be pressed against any surface and held in place until the foam sets. The PU foam is a natural sound damper, and the airgaps behind the boards, also provide some thermal and sound insulation. This is far cheaper, quicker and needs less skill from the operators, reduces fixings to the minimum, and also the surface finishing, with no multiple screw indentations to fill and cover.