How to prevent creaky floorboards
Creaky noises arising from floorboards are irritating and we have all most likely experienced the frustration of this in our lifetime, whether at home or in a building we have visited.
We have found that most commonly, creaks or squeaks tend to occur in older buildings, however we have also still experienced this within newer buildings too. The creaking noises tend to be amplified through footsteps to the affected area which can be a real nuisance for those having to endure this on a daily basis.
Causes of creaking floors
There are a number of reasons for creaky floors. These can be; friction caused between two hard surfaces rubbing together, movement in a floor, incorrect installation of a timber structure, flex in the joists, incorrect fixings or joists that are not level.
A lot of structural flooring used in todays new build development is tongue and grooved. This should help prevent some movement and creaking issues if installed correctly by allowing the flooring to act independently to the joists.
However, in some cases the floorboards are square edged, which can cause friction when rubbing together and can in turn create the annoying creak when walked over.
In addition to this when floorboards are nailed down to the timber joists, over time, the timber dries out and the floorboards then start to move up and down, which causes the bothersome squeak against the nail shaft itself.
Another trigger of aggravating creaks or squeaks are when there are slight gaps or cavities between the timber Joists and the timber structural floor.
Timber is a natural product and is used for joists within buildings. With natural products, we cannot expect for these to be completely flat or evenly level and as a result of this, when floorboards are laid over the top of the irregular joists, cavities can occur between the joist tops and the flooring and will cause the floorboards to depress when walked over. In turn this creates the unwanted noise from the floorboard moving.
How we can help to reduce creaking floors
In order to tackle creaky floors, either the whole floor or specific floorboards must be treated and Hush can advise you on few solutions that will prevent nuisance noise.
Solution 1 – Replace problem floors in existing buildings or prevent in new build situations
In the first instance, to treat the whole floor, we would initially recommend for the floorboards to be completely removed, this can be done very carefully if the flooring is to be re-used.
Once the floorboards are removed, the joists must be checked removing all nails. After checking the joists, if there are any uneven areas or different depths within the wood, Timber Shims can be added to the top. A Timber Shim is a thin wedge of wood that is secured to the joists to make them level.
Once the joists have been levelled out as much as possible, we would recommend our Hush-10 Joist Strips to be applied to the top of the joists. These joist strips are made from our unique felt and are used for two reasons, to rid of any remaining unevenness in the joists and also to provide additional isolation, providing an acoustically dampened floor.
Once this preparation has been made, either the existing flooring can be re-fitted, or our Hush Panel 28 can be floated over the strips to provide a fully floating structural floor. Hush Panel 28 has been designed and developed as a sound reducing floor panel which can be used as either a structural or overlay floor board (Hush Panel 28 to be used if joist centres are no more than 400mm. Other Hush products to be used if centres are wider).
Excellent results are achieved in both refurbishment and new build projects when using Hush-Panel 28 as part of a sound insulation system for separating floors.
If Hush Panel 28 is used, it will need to be isolated at the perimeter walls using our Hush Seal 20 ensuring no unwanted noise or noise nuisance will occur around the finished acoustic floor treatment.
We would always recommend the Hush Slab 100 Sound Absorber is added between the joists to improve the acoustic performance when the floor is removed.
Solution 2 – Retrofit solution
In order to tackle creaking or squeaking of floorboards underneath carpeted or other floor finished areas, the offending floorboards must be screwed down very tightly.
Once fixed down, our acoustic underlay mat can then be laid over the floor. Hush Mat 15 is our uniquely engineered acoustic rubber matting. It contains high levels of mass, contributing to airborne sound reduction, giving excellent impact sound reducing performance.
Hush Mat 15 acts as an acoustic underlay, without the need for any additional carpet underlay and therefore dampens the noise from the contributing factors to creaky floorboards.
Solution 3 – Prevent nuisance creaks in floors with metal web joists
Web joists can be used for floors and roofs, as they provide an easy installation with their open design.
They make fixing pipes or electrical cables much faster than traditional construction methods because there’s less wood needed in a flooring job compared to other types of buildings!
Metal web joists are also a good choice for your floor because they have the ability to reduce noise transmitted through it versus softwood floors. Metal web joists offer a high degree of rigidity which can be far greater than softwood joists, which means they have a better tolerance to deflection.
Deflection, to put it simple means how much the joist bends or sags under load and this is one the most popular reasons why we have creaking floorboards.
The NHBC stipulates that deflection or vibration should be addressed by designing the floor in accordance with BS EN 1995-1-1 and its UK National Annex. Or design to deflection limits, based on total dead and imposed loads for combined bending and shear of 0.003 x the span, with a maximum deflection of 14mm where strutting is provided, or 12mm where strutting is not provided.
In the experience of Hush Acoustics, based on the enquiries we receive, one of the main reasons why the level of deflection in metal web joists is greater than expected is because the joist centres are too far apart. Yes, it is perfectly plausible to use posi-joists at 600mm centres, but it can push the structural strength to its limits where other factors are outside the architect’s control.
Therefore, when designing a building with metal web floor joists it is far safer to build to joist centres of 400mm to prevent the risk of excessive deflection.