How to Soundproof a Wall
Noise generated by thoughtless neighbours can make life distinctly unpleasant, if not intolerable. Although it is difficult to block out unwelcome sounds completely, it is possible to reduce the amount of noise passing through a shared wall.
- Bolster chisel
- Claw hammer
- Craft knife
- Electrician’s screwdriver
- Electirican’s pliers
- Filling knife
- Mastic gun
- Plumb line
- Tape measure
- Tenon saw
- Try square
- Wire strippers
Sealing gaps in the shared or partition wall is one obvious way to reduce airborne noise. If necessary, remove skirtings and floorboards close to the partition wall so you can repoint poor mortar joints and fill any gaps around joists that are built into the masonry. After replacing the skirting and floorboards, seal any gaps between them with a flexible mastic.
It may also be worth repointing the wall in the, and plastering it to add mass.
Lining the Wall
The soundproofing of a partition wall can be greatly improved by building an insulated lining. However, its effectiveness will depend to some extent on the construction of the wall, whether or not there is a fireplace, the location of electrical or plumbing fittings, and the proximity of windows.
The lining— constructed in a similar way to an ordinary— is fixed to the floor, ceiling and side walls, but not to the shared wall itself. The gap between the lining and the wall is filled with glass-fibre or mineral-fibre blanket insulation, and the lining is clad with two layers of plasterboard.
Adding a lining to the shared wall of an older house may mean having to modify a moulded-plaster cornice; and the size of the room will be reduced, whatever the age of the house. Nevertheless, the benefits are likely to compensate for the disadvantages and effort involved.
What to do first
Switch off the electrical supply at the consumer unit, and replace any fittings attached to the shared wall with junction boxes in readiness for relocating the fittings on the new lining. If your experience is limited, hire an electrician to do the electrical work for you.
Remove the skirting carefully for re-use. Mark a line on the ceiling 100mm (4in) from the shared wall. Drop a plumb line and make a similar mark on the floor below.
Fixing the lining sole plate to the floor presents few problems; but if the ceiling joists run parallel to the shared wall, then you may have to nail noggings (stout battens) between them to provide secure fixing points for the lining head plate.
Erecting the lining
Nail a 75 x 50mm (3 x 2in)head plate and sole plate in position, with their front edges on the marked lines — this will leave a 25mm (1in) between them and the wall. Nail matching vertical studs between them at 600m (2ft) intervals. Mark the position of each stud on the floor and ceiling to help you relocate them when fixing the plasterboard.
Hang floor-to-ceiling lengths of 100 x 600mm (4in x 2ft) insulating blanket between the studs, tucking the edges behind the framework. Skew-nail noggings between the studs to serve as fixing points for shelving or electrical mounting boxes.
Check that the power is still switched off at the consumer unit, then run short lengths of cable from junction boxes to the new mounting-box locations.
Cover the framework with plasterboard 12mm (1/2in) thick. Fill the joints and seal around the outer edges with mastic. Nail a second layer of tapered-edge boards over the first, staggering the joints and placing theabout 150mm (6in) apart.
Fill and tape the joints between the boards, then nail the skirting board in place. Mount and wire the electrical fittings, sealing around the edges of flush-mounted electrical mounting boxes with mastic. Seal the lower edge of the skirting board, too.