Lewis Deck with metal web timber joists
Creaky wooden floors

Creaky wooden floors

Don't let them impact your build quality

We often talk to visitors at exhibitions about the issue of noisy floors, usually the issue of squeaky wooden floors, whilst our systems are often used to provide the fire and acoustic separation in an apartment situation, it is creaks and squeaks in a traditional timber boarded 1st floor that self-builders are keen to avoid.

No matter how well built a chipboard, plywood or tongue and groove floorboard floor is installed, screwed and glued, it is a system that includes many joints and a medium (the wood) that will have a moisture content and will shrink as it dries out.  All the board systems have a limited spanning capability and therefore if a single joist develops some movement, there will be movement in the boards above leading to noise and that usually means a squeak or creak that is difficult to do anything about, not to mention that soft spot in the floor where the flex occurs.  Just a little annoyance that can take the edge off an otherwise extremely well finished house.

Our floor systems and typically the Lewis Deck for self-build projects, provide floors that end up being jointless for most projects, they also span much further than the joist centres that they are used with and therefore, even if a timber joist could move below, it is unlikely to as the deck will carry the loads to the joist either side and in most cases a number of joists either side.  This gives a very solid feel to the floor and removes the issue of creaky and squeaky wooden floors.

The Lewis Deck, with either a liquid screed or a concrete installed over the top is usually 50mm in depth, this can be reduced to 36mm if required and this suits some refurbishment projects where the extra height can be an issue.  We also have the Max4 system where build-up heights are at an absolute premium and can be installed at just 15mm.  These system thicknesses can also include underfloor heating pipes.

We are often also asked what happens if the services running within the floor zone need to be accessed to effect repairs, this is difficult with a concrete floor to go in from the top and the recommendation is to access them through the ceiling.  This advice also works for timber floors as to access through a timber floor board usually means cutting off the lips that hold them together and introduces further opportunities for movement and noise. We have all be in old houses where the plumber has added pipework for a central heating upgrade and there are those spots in the floor that flex and squeak because the boards have been cut to get to the space below.

The systems are also used to create floors for underfloor heating, wet-rooms and externally as balconies and terraces.  If you would like to discuss this further, please get in contact.


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Do I keep my joist centres at 400mm when using Lewis Deck?


One of the great things about using Lewis Deck is that it opens up a number of different options for you and one of them is around joist centres you can work with.

Traditionally we see the vast majority of architects and designers insisting that timber joists be installed at either 400mm or at most 600mm because this is the limit of what timber floor systems will effectively span to. Now with Lewis, because of its unique profile (with the dovetails dimensions) and the way it interacts with the thin (50mm) screed laid on it, you can actually go much wider than these figures.With a 50mm screed, on top of the sheets, Lewis allows you to have unpropped centres of up to 1200mm (1.2m). Even at these much wider centres Lewis will allow you to have a permissible load of 14.8kN/m2, which in English is just under 1.5 Tonnes per m2. Now this might sound fantastic, and it is, but in reality for 95% of new build homes this figure won't really make too much difference to what you were planning on doing with upstairs.What it does mean though is that at your normal centres, of approximately 600mm, your floor becomes so much stronger than traditional forms of floor structure that it allows you to do things on the 1st floor that you take for granted on the ground floor.First of all is the obvious one, you get a solid floor, meaning no more squeaky floor boards or hearing people walking around upstairs and knowing exactly where they are up there! Having the solid floor gives you the chance to have a very efficient underfloor heating system (see our applications section for more details) which in most cases will probably mean a slight reduction in your fuel bills.Other big benefits of having a stronger floor upstairs include being able to have either thinner tiles or much heavier tiles than you can use on timber floor systems. The screed and Lewis working together pretty much stops any deflection in the floor meaning that these types of tiles won't crack or move and lift over time as the floor doesn't move or deflect!So in conclusion yes you can have much wider joist centres than the 400mm centres that you normally see on new developments but even if you wanted to keep them the same by using Lewis Deck it opens up so many benefits that you just aren't able to incorporate with traditional timber floor systems. However the joist centres are usually controlled by the load capacity of the joist and not the spanning capacity of the Lewis Deck.


Do you fix Lewis Deck down to the joists?


The short answer to this is no Lewis Deck doesn't have to be fixed down.

Generally the reason why people choose to use Lewis Deck over more traditional floor systems is that they are looking to enhance the upper floor that they are working on. So if you are going to be looking at using Lewis then you might as well look to incorporate its full range of benefits. One of which is the major uplift in acoustic performance that you get from using the system.Getting the best results, acoustically, is achieved by laying the floor as a floating floor. This then creates separation between the supporting floor joists and and the steel deck. To enhance this further introduce a resilient strip on top of the joist. See below.[caption id="attachment_559" align="alignnone" width="300"]Lewis Metal Dovetailed Sheeting Deck with acoustic Sylomer resilient strips Lewis Metal Dovetailed Sheeting Deck with acoustic Sylomer resilient strips[/caption]When it comes to determining which of our acoustic resilient strips to use (because we have a few of them and they all do different jobs depending on the use of them and the type of structure below) we are happy to help you come up with the correct option that suits your project the best.A standard Lewis Deck floor detail (such as the detail above) easily achieves UK requirements for acoustic (as well as fire) resistance for residential separating floors. Higher performance standards are easily achievable too. Because of this we have seen Lewis Deck used frequently in in bespoke projects such as live music/ theatre venues, cinemas, recording studios, specialist test labs, plant room floors and many other commercial applications.Note: some joists my require lateral stability and therefore lateral restraint straps or timber noggins or a sacrificial timber board may be required to achieve this, your joist supplier or designer will be able to provide this information, in some cases the Lewis Deck can be fixed down to provide this action if required.Please feel free to give us a call and discuss this further should you wish to do so.

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