In domestic situations you will generally be wanting to soundproof either a brick/block wall or a stud partition wall.
New Build Stud Partition
For stud partitions that are new build use our acoustic mineral wool in the stud cavity. For even better performance, use the 2FTex quilt in the stud cavity. 2FTex is far superior to mineral wool as it has a layer of acoustic barrier sheet laminated in the middle of the product. Hang at least one side of the wall on resilient bars and use at least one layer (two is much better) of T50 or VL-65 acoustic membrane in between the plasterboard sheets. Isolate the perimeter of the framework with the RFT50 High Performance Resilient tape.
Take care to seal the perimeter and joints with our acoustic sealant and ensure you maintain resilient isolation from the framework using our neoprene strips beneath the battens. Make the stud cavity as deep as possible or better still use independent frames for each side of the wall. Offset the second layer of plasterboard to reinforce the seams in the first (see diagram below).
This is for guidance only. If you are unsure about your DIY skills it may be better to contact an experienced builder.
Stick the T50 membrane to the first layer of plasterboard then add the final layer of plasterboard offset against the first.
If you have an existing stud wall and can afford to lose a few millimetres from the room, look at our CAD20-WP panels which glue onto the existing plasterboard; this isolates the further two layers of plasterboard which should be glued on top of the CAD20-WP. If space is at a premium reasonable improvements can still be obtained by sticking two layers of T50 or VL-65 acoustic membrane to the plasterboard before screwing a thick sheet of plasterboard over to finish.
Brick Party Walls
For brick party walls you can also use CAD20-WP panels with additional plasterboard. This will take up only 50mm of space although the framed approach (on page 1) is a better option if you can afford to lose more space (10–15 cms depending on batten/stud depth). The latter option should include either T50 or VL-65 acoustic membrane between the two sheets of plasterboard, all hung on resilient bars. The cavity space should be as deep as possible and acoustic mineral wool should be included in the cavity. Even better performance can be achieved by first bonding and fixing our high performance 2FTex quilt to the wall – this can also be used to isolate the framework. This material is very heavy and does require glue and rosette fixings. If using the 2FTex first there is no need to put the neoprene between the battens and the wall as the 2FTex isolates them. Ideally, rather than fix the battens through the 2FTex into the wall, build the frame 20mm or more away from the wall but with the head and sole plates still isolated by lapping the 2FTex across the floor and across the ceiling first. A cross-section side elevation is detailed below:
The results you will get when doing this will depend on workmanship, materials and methods used, but improvements can sometimes be limited by ‘flanking noise’. This phenomenon is where a percentage of the noise may not only be transmitted directly through the wall but also via adjacent walls connecting the party wall, or even through floor/ ceiling slabs connected to the party wall. This can vary from one project to another and depends on the existing structure. For example, if the building is in-situ concrete where the junctions are strongly coupled (as shown in the following diagram) then treating the ceiling and floor as well may also be necessary.
'Boss plaster', where the plaster has lost its strength and adhesive bond to the wall, can also present weak spots for noise/sound transmission and cause poor acoustic perfor-mance. If the plaster sounds hollow when the surface is tapped, consider getting the walls re-plastered as this can greatly improve the acoustic effectiveness.
Interlocking flues and fireplaces, recesses for kitchen ranges and recessed cupboards, especially when back-to-back, can also cause sound transmission problems.
Similarly, the diagrams below show how, in a worst case scenario, if the separating wall was built incorrectly, treating the party wall with soundproofing would have very little effect as the sound will simply be transmitted via the space where the wall should have been butted and tied into the existing blockwork. In this case it is necessary to treat the party wall and the adjacent walls to notice an improvement.