Noise from underground tube trains can be a nuisance and difficult to effectively silence. Tube train noise is predominantly low frequency and is created by the air movement forced through the tunnels by the trains and the sound emitted from the wheels on the tracks. This noise is transmitted through the ground and up into the fabric of buildings making floors and walls resonate. The noise is more noticeable at night or when there are no normal household background noises to help mask it. When a train is passing, if you put your hand onto a hard floor surface or wall, you should be able to feel the vibration emitted from the train. It is this low frequency vibration that transmits the noise that you hear into the rooms.

Acoustic Solution for ground floors

The ground floor is the best place to start and if the floor is timber suspended on joists, replacing it with concrete incorporating a floating screed will give the best results. Normally a concrete base at least 250mm thick would be installed and when cured, a 75mm concrete screed installed on top and isolated using 10mm R10 resilient recycled rubber sound insulation. This combination will reduce the vibrations from beneath being transmitted through the floor and into the room. If replacing a timber suspended floor with concrete is not possible, a floating floor can be installed on top of the existing wooden floor using the same resilient R10 but with layers of 2mm SBM5 Soundproofing Mat beneath. The more layers there are the more efficient the soundproofing will be. On top of the R10, 18mm QuietBoard, a t&g high density acoustic flooring should be laid. More information and installation instructions for these systems can be viewed on our web site by clicking the following link

If for whatever reason, the additional thickness this system requires on timber floors, SBM5 and QuietFloor Acoustic Underlay can be used as an alternative, but of course would not be as efficient due to the lower mass these products have. But if more layers of the 2mm SBM5 are used it will increase the mass and therefore make the sound insulation more effective.

Whichever system is preferred, the floor surface should be covered with carpet and felt underlay unless the QuietFloor Plus has been used when no additional underlay is required. If a hard floor surface is being considered, it should be at least 18mm thick and installed on top of either of the two options previously mentioned.

It may be worth mentioning here that anti-vibration solutions are now available to isolate the rails from the track to reduce noise.  More information on this can be viewed on the web site by clicking on the following link

Acoustic Solution for upper floors

Most upper floors are timber suspended and can be treated as described above for timber suspended floors using our Floating Floor System. If the floors are concrete, the same solutions can be used as described for timber floors but with the omission of the SBM5 Soundproofing Mats because there will already be enough mass in the concrete.

Acoustic Solution for walls

Noise vibrating up the walls will transmit sound into all of the rooms the wall forms part of and the only way to address this is in a similar way to the floors and that is to form a ‘floating wall’. A floating wall take up about 45mm of room space and is easy to install as a three part system that we call our Thin Wall System. More information and installation instructions for the Thin Wall System can be viewed by clicking on the following link
or if space is a problem, we can also offer a thinner system that takes up about 27.5mm and is called Ultra Thin Wall System. The following link will also give more information including installation instructions
Current prices for all of our sound insulating products and systems can be seen on our web site or you can call us to discuss your noise problem and solutions in more detail.

Written by Stephen Young

© Sound Service (Oxford) Ltd. 2007