DIY Domestic floor Soundproofing

Floor Soundproofing Help

Even in new build houses and flats, that are built using the correct materials and methods, loud noise produced by music and shouting etc will always be heard and can be particularly worse in the evening when normal daytime background noises have stopped and the ambient background noise is therefor much less.

If you are suffering from noise problems travelling through a floor you firstly need to address the question "is the problem airborne or impact?".
Airborne sound is from something like a TV whereas impact noise is from footfall.

If the problem is impact noise then the following solutions can be employed:-

BASIC FLOATING FLOORS

A floating floor is one that is 'isolated' from the existing structure by a 'resilient' layer. The best sound insulation results can be achieved if the floorboards are first lifted and our 2FT45 quilt or the lesser performing 100mm Fire-Safe Acoustic Mineral Wool install between the joists. The floorboards should then be screwed back down into the joists to prevent them 'squeaking' when walked on before the floating floor is installed. Insulation between the joists and a floating floor is now required by the new Building Regulations for all new build and conversion projects. Next you need a resilient layer fixed over the base floor and a new Tongue and Grooved floor is placed on top with all the T&G joints glued and sealed togeather. We have a number of options for the resilient layer so call us to discuss. 22mm T&G is a good overlay board but for even better results our Cement Impregnated Particle Board can be used. This floating floor system also ideal for uprating concrete floors. It is imperative that the resilient layer keeps the T&G from touching the walls and the skirting from touching the T&G or the system wont work. Only then should the small gap be sealed with flexible sealant.

Installing the system above will increase the floor height by approx. 30-40mm so all the doors will have to be adjusted accordingly at the thresholds.

HIGHER PERFORMANCE FLOATING FLOORS

Older type square-edged floorboards allow sound leakage through the gaps between them. This can now be greatly reduced by installing two layers of our 2.5mm thick T50 Damping Membrane with the second layer offset so overlapping the joints of the first. Our Spray Adhesive is ideal for fixing these in place.

Replacing the 100mm Mineral Wool in the cavity with our High Performance 2FT45 Quilt will greatly improve the performance.

The systems above will reduce both impact and airborne noise between floors.

UNDERLAYS FOR CARPETS

If it's not practical to fit a floating floor system then another option is to swop any existing carpet underlay for our Acoustic Carpet Underlay. Our Acoustic Carpet Underlay is designed to reduce impact noise which will benefit the neighbours below but will do little to reduce any airborne noise between floors.

If the problem is solely airborne noise then the following solutions can be employed:-

Seal any gaps between the floorboards with our Acoustic Sealant to make the subfloor airtight. Fix 2 layers of T50 Damping Membrane over the base floor before replacing the underlay and carpet. This is the absolute minimum you can do to improve airborne sound but is often not enough of a solution.

Better Still, if you are prepared to lift the floorboards, add our 100mm thick Fire-Safe Acoustic Mineral Wool inbetween the joists. then add 2 layers of the soundproofing mat over the top before replacing the underlay and carpet.

Replacing the 100mm mineral wool with our High Performance 2FT45 Quilt before adding 2 layers of T60 soundproofing is a good option.

If you don't want to lift the floorboards then seal the floor with a layer or two of soundproofing mat then and add Quietfloor Slabs before replacing the carpet.

Squeaky Floorboards

Many people find squeaking floorboards extremely irritating and they are best dealt with before adding any soundproofing materials to a floor. This noise is usually caused by boards rubbing against boards or the joists they are fixed to. The most common problem we find is due to poor nailing when undersized nails have been used or the nails are spaced too far apart. The best way to sort this out is to screw, rather than nail, the boards down securely.

We have also found that defective materials are another cause of this. Warped or twisted joists, bowed subfloors/wood sheathing can all cause the materials to rub against each other. Wherever floor materials move against each other squeaking will result. Sometimes all that is needed is to add some mineral oil around the squeak but this tends to wear off after time as the problem can re-occur. This however can be useful for tongue and grooved flooring that has weak or broken T&G links.

PLEASE NOTE:

The results you will get when doing this will depend on workmanship, materials used, 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 touching the separating floor and this can vary from one project to another. It often depends on the existing structure. For example if the floor is a concrete floor slabs built correctly into the wall then the floor acts like an added resistance to the sound trying to 'flank' through the wall but if the floor slab is not built in but butted to the wall and the wall leaf is continuous between houses there will be excessive flanking transmission and you would have to treat not only floor or ceiling but also the walls as well.

Another typical example of bad conversions is where the end joists run parallel to the party wall. Insulation may have even been installed in the past but the gap between the end joist and wall was left. This may have been because someone thought it wouldn't make much difference but it will ! In siutations like this, without taking things apart to investigate, there may be hidden problems which will again limit the improvements that would otherwise be achieved.