Soundproofing Solution to Reduce Noise Through Walls
There are many good soundproofing solutions to reduce noise travelling through walls. One of the most common party wall soundproofing solutions would be to install a metal frame system that is independent of the wall – say a 75mm met-sec wall. This would need to be kept 20mm off the face of the existing wall. Then install a RW45 Acoustic Wool (min 45kg/m3) within the metal frame and finish with 2 layers of 15mm acoustic plaster board. However, this system comes at a space premium as will lose you about 115mm with skimmed 15mm sound board, or 125mm with two layers of 12.5mm soundboard.
Here is a detail of an independent type of system below, though you are going to lose approximately 100mm of room space when building an independent metal wall solution (min gap to the wall 20mm)
Also, it’s worth checking if you have a disused chimney breast in the house, as this can be solid between older properties and sometimes people connect their TV’s soundbars, speakers etc. to the chimney breast the base sound (lower frequencies) can travel through the solid construction. In this instance you can add baton, resilient bars, acoustic wool and soundboard to the chimney breast which should help.
Another issue may be joists which over-hang the cavity and touch the other joists or the wall in the neighbouring property which can quite a difficult to remedy. Also, on older houses they often used a “soldier course” of brick, the bricks were laid on end, hence the word “soldier” as opposed to being laid flat – to see if this is the case, you need to lift a couple of floorboards along the party wall and have good look at the pointing on the soldier or standard brickwork.
On closer inspection you’ll often find gaps in the masonry mortar, as the bricks are harder to lay properly due to the confined space between the joists. Also, also the mortar may degrade and crumble due to the general movement in the timber joists (deflection) as well as shrinkage. In most cases the mortar can be replaced/repointed. In some cases, large areas of masonry may be missing which will need to be replaced. You can also install some extra acoustic wool within the joist voids against the party wall, which should further improve the soundproofing.
In a nutshell soundproofing is the art of trying to prevent vibrations crossing party walls and floor partitions.
Getting the acoustic design right from the word go, is key, and APT Sound Testing can help in all areas of sound insulation design and sound testing. Please get in touch on info@aptsoundtesting.co.uk to request a quote or call us on 07775623464 or 01525 303905 to discuss your development.