CDI Innovative Construction Materials Ltd (CDI).

Here at CDI we provide a range of innovative building systems, including high performance structural floors on timber or steel joists, floor reinforcement, wet floor systems, underfloor heating, insulated concrete roof & ground floor systems for high load bearing situations, and a non lead flashing system for roofing.

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for self build & renovations

Our innovative products cover a wide variety of applications and potential uses.

They offer numerous benefits and solutions for the design team right through to the end user of the building and they have been on projects all over the world. Look below for an overview of the products within our range.

Ideally suited to all fast-track, lightweight Offsite building methods including Timber Frame, Light Gauge Steel Frame, Structurally Insulated Panel (SIP) systems, Insulated Concrete Formwork (ICF) and also Traditional, brick and block building methods.

Video Case Study – Kingswood Warren Park renovation into luxury apartments using Lewis Decking & including underfloor heating

A discussion of the merits of using Lewis and underfloor heating is available to view here this includes a number of projects that include underfloor heating at both ground floor and 1st floor.

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Lacomet – How come it has no scrap value?


Lacomet – How come it has no scrap value?Many of the projects that we get involved in starts with a phone call or email to us from someone researching replacing stolen leadwork. Many of these are old buildings, such as schools or churches, where this isn’t the first time that the lead has been stolen and they call us fed up with having to replace it again full in the knowledge that they will more than likely go through the same problem once more in the near future if they continue to use lead.One of the big benefits that Lacomet FL brings to a project is the fact that it has no scrap value and therefore the chances of it being stolen are massively reduced.Due to the 2 thin aluminium layers, and its five layer total construction, it is of no value to thieves. Lacomet can be recycled but the polyester based coating would need to be de-laminated first and the amount of recovered aluminum is then very low, in fact it would be easier and more profitable to collect empty drinks cans than to mess about stripping Lacomet down. We can also supply stickers that can be placed in strategic locations informing people that what is now on the roof is not lead and that it has no scrap value.


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.


Can joists and decking for Lewis FastSlab be cut by hand e.g. hacksaw or angle grinder?


The FastSlab beams and the Lewis Deck are generally cut on site. Typically we see the Lewis Deck being cut with an angle grinder, a circular saw or a powered hacksaw.

The FastSlab beams can be cut with the same – the hacksaw possibly being the best option here.

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Latest Events

and Exhibitions

Latest Blog

CDI 2018

Lewis Deck with metal web timber joists

Creaky wooden floors

19th October 2017

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. …

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CDI Added to Updated Sourcebooks

30th August 2017

It’s always good to get a little more advertising in. From today we are now listed in both Real Homes and Period Livings updated sourcebooks. You can find us at both through the following links: CDI Innovative Construction Materials CDI Innovative Construction Materials  

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Granite tiles and shower tray laid over a Lewis Deck and Concrete floor upstairs over timber joists

Travertine wetroom by Craig Bills

30th May 2017

Craig Bills is a master tiler and has been installing wet-rooms using Lewis Deck and concrete for over 20 years, he is a passionate advocate for the Lewis Deck system in wet-rooms and bathrooms as it give an opportunity for the floor to be 1 piece of waterproofed concrete.  This makes a very robust and …

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