SOUNDPROOFING A GARAGE
Effective soundproofing of a garage is rarely possible due to the lightweight structure of the walls, roof, windows and doors plus the confined space usually available. The best that can be achieved is a reduction in the noise breaking out of these buildings. Because the windows and doors are the weakest points, these should be addressed first. Assuming it is a masonry built garage the following can be utilised but if it is a timber built garage, they are usually too light and small to derive any substantial benefit from sound insulation so we suggest an alternative location is found or simply accept that the solution offered below will not be as effective but will still give an appreciable soundproofing result.
WINDOWS
If light through the windows is desired, they should be triple glazed with different thicknesses of glass at staggered intervals and installed so as to be completely sealed. If light is not an issue, the window reveal should ideally be bricked up. As this is a fairly permanent option, it may be preferred to infill with a more easily removable alternative when required. In this case we would suggest making a removeable window plug. This could be inserted whenever required, but it must be an airtight fit when installed so may require draught proofing seals. To read more about DIY window soundproofing click HERE
DOORS
Thin pressed steel up and over doors are impossible to insulate so should ideally be removed and bricked up or replaced with our heavy solid wood Acoustic Doors, fitted so they are sealed when closed. If this is not possible, assuming there is an alternative entrance, a concrete block wall should be built be built against the inside of the door or alternatively, a timber stud partition should be built on the inside of the door, infilled with Acoustic Mineral Wool (AMW) and clad with two layers of 12mm plasterboard. We supply easy to install Acoustic Doors and DIY door seal kits which can be seen HERE
DOUBLE DOOR ENTRY
A double door entry system will be more effective at reducing noise breaking through. This entails two Acoustic Doors fitted so one opens outwards and the other opens inwards. Both should be fitted so as to be sealed when closed as previously described. If you can't afford to use two of our doors then you could consider using two 1 hour fire rated doors and then uprate these using our seal sets for doors by clicking the following link here
ROOF
The supporting joists of a flat roof should be ideally infilled with our Acoustic Quilt or AMW, our Acoustic Membrane should then be stapled to the underside of the joists followed by Resilient Bars screwed to the underside of the insulated joists and two layers of 12mm plasterboard screwed to the bars. This will not be ideal but height rarely allows for more effective solutions. With pitched roofs, if access allows, AMW can be placed between the rafters with SBM5 stapled to the rafters and then clad with a layer of 12mm high density plasterboard.
FLOORS
If the room to be insulated is on the first floor, the ceiling below must first be insulated with our Acoustic Membrane, Acoustic Quilt and Resilient Bar system as described above. If the floor is of the square edged variety, it can be overlaid with SBM5 to seal up the joints. A floating floor using Acousticel R10 as the resilient layer with our high density QuietBoard acoustic flooring installed on top.
EXPECTED RESULTS
Before installing sound insulation as described above, your garage would have had a very poor insulation value which would no doubt, have wound your immediate neighbours up. As the windows would have been one of the weaker points, the sound insulation value of these would have been no more than 24dB across the frequency range.
This means if music was being played at 110dB, 86dB of noise would be penetrating the window, which is still pretty loud. After installing the above described materials, and the window was triple glazed as first described, the window insulation value would be improved to around 34dB but if blanked off with the plasterboard and M20AD system, the insulation value would be equal to the walls at around 40-45dB.
This means a maximum of 70dB would still be penetrating the walls of the structure. A vast improvement but still too loud for nearby neighbours, particularly at night when other background noises are very much reduced, so if space permits, further measures are necessary. A 'room within a room' will have to be created. This entails the installation of timber studs installed around the walls and across the ceiling constructed 12mm from the existing structure, freestanding and not fixed.
The studwork should be infilled with our Acoustic Mineral Wool AMW or ideally our Acoustic Quilt with SBM5 stapled to the outside of the stud and clad with two layers of 12mm plasterboard, the second layer overlapping the joints of the first. The sound insulation improvement should give the walls of the garage an insulation value of at least 52dB which is a much more satisfactory result and should please your neighbours.
INTERIOR
Now the outside shell has been insulated, you will want to reduce the reverberation of sound within the room. Reverberation actually amplifies the sound originally emitted so the sound has to be absorbed. To achieve this we recommend our Melamine Foam or more effective Echosorption Plus is used to line the walls and ceiling. This will reduce any reverberation and further reduce the amount of noise breaking out from the garage.
DISTANCE
Depending on the level of background sound, noise usually decreases by 5db for each doubling of distance, so it is possible that a sound level of 110db generated within the garage can be reduced to as little as 40dB from a comparatively short distance away. However, low frequency sound will always be a problem and can be further reduced if our Echosorption Plus is installed onto 50mm battens infilled with AMW50 as already described.
VENTILATION
Now all this work has been done, the 'drums' have been set up and you are ready to produce some serious sounds, more air may be required after a while so it may be prudent to install a ventilation system. For this it will be necessary to form a hole through the wall on each side, one at the bottom and the other at the top of opposite walls. Using 12mm ply or MDF, a simple baffle can be created by installing an open ended box over each side of the holes so there is no direct line of sight into the room. The interior of the boxes and the walls must be insulated with fire resistant sound absorbing foam (SA25FR) to absorb some of the sound that will exit through the vents. You could also consider using our Acoustic Vents.
