What is soundproofing glue?
While to first appearances soundproofing glues may look like any ordinary glue, they are specifically designed to reduce mechanical sound transmission through layers. Cheap and versatile, it works by putting extra distance between two layers of rigid building materials such as plasterboard or OSB. Sound would typically hit the wall and vibrate it, causing a resonant wave to occur on the other side of the wall, thus passing along the sound. The addition of soundproofing glue between these layers causes the wave to decay much faster, thereby allowing much less of the wave to travel through to the next room.
How effective is soundproofing glue?
The difference between using and not using a soundproofing glue can be surprisingly big. Because it is applied randomly and sits between two layers of other materials, its effectiveness is dependent on its application. However it is worth noting that multiple layers will increase its effectiveness. It is also especially good at reducing low frequency noise such as the bass from a decent sound system or explosion sound effects in a home theatre.
How is soundproofing glue installed?
Once one layer of rigid wall surface has been erected, the panels for the second and subsequent layers are laid down with the back facing up. The glue is liberally applied in a random pattern using a caulking gun across the entire surface of the panel, ensuring there are no substantial gaps. It requires no trowels or other specialised equipment to apply and once the panel is covered, it can be fitted into place, lining up the bottom edge first and pressing it firmly. This will allow the glue to spread, coating the inner surfaces more evenly. The panel should also be screwed into place before the glue has had time to dry so the job will likely require two people.
Relative cost and effectiveness
Compared with other specialised acoustic insulation, soundproofing glues are very cheap to use. Since they don’t require any expertise to apply, labour costs can often be absorbed or negated, and are especially cheap if you were already going to use a double layered wall since it would have to be glued anyway.
Shortcomings, potential improvements
While not a cover-all solution, there is little reason not to recommend this type of application for soundproofing. It becomes particularly effective when combined with other forms of acoustic insulation such as sound dampening plasterboard.
