Railway Station to House Refurbishment, Cambs

Railway Station to House Refurbishment, Cambs

First 0.7mm thick Lewis Deck Project

One of the big elements that we at CDI try and focus on is pushing the boundaries of what can be achieved with floor technology and trying to improve the overall performance of our own systems.

To this end with using Lewis Deck you are able to open up the spans between a joist floor layout up to 1.2m without having to use temporary propping. Which when you consider most upper floors that have timber floors generally have joists at 450mm to 600mm centres, 1.2m is a very big improvement.

However, what do you do if you want a thin concrete ground floor but you have a spans of 1.5m and the ground level is over a metre below where the finished floor level needs to be.

This is the problem that Godfrey & Hicks, of Fordham, found themselves with when a client asked them to completely renovate a 19th Century railway station into a new house. As you can see from the picture below the existing floor was timber laid on thin, rotten timber floor joists that needed to completely removed.

IMG_1437

Once removed they were left with clear spans of 1.5m which left them with a problem. Do they replace like for like and put new timber joists in and keep the timber floor (that they didn’t want) or do they look at putting in a thicker concrete slab on a permanent shuttering system. With these systems starting from approximately 110mm thickness this would then add a lot of weight onto the existing (old) foundations and also massively reduce the floor to ceiling height and meaning that all of the door heads on the ground floor would need to be altered to make sure they passed building regulations.

20170913_083208 (Temporary struts were installed so timber sheets could be laid as a safe working deck prior to the Lewis sheets being delivered to site).

Godfrey & Hicks got in touch with us after finding Lewis Deck on our website. They explained their issue in that the client wanted a concrete floor but they had 1.5m spans and they didn’t want to use new joists or a thicker concrete due to the issues these other systems would bring.

Luckily for us (and them), over the last 12 months, we had been testing and trialing a thicker gauge of steel on Lewis Deck. Our standard Lewis Deck uses o.5mm gauge steel and with this system, as described earlier, we can achieve open spans, without propping, of 1.2m and still maintain the 50mm of screed.

We now have a new 0.7mm gauge steel thickness that has gone through the testing procedures and come out the other end with much improved results. One of the main improvements that come with the thicker steel is that the spans we are able to go to are increased. With the 0.7mm gauge we are able to meet the 1.5m span problem that this site had and also increase the overall maximum spans Lewis is capable of achieving from 2.5m to 3.0m (please ask us for more information on this if this could help your scheme).

This new thicker Lewis was the ideal material for this station refurbishment as it allowed the client to have the concrete floor they wanted and it didn’t affect the ceiling heights or impose to much load onto the old foundations. It also meant that the contractor didn’t need to replace the timber floor joists thus saving time and money on the project.

The project was also ideal for us as this was the first time we could showcase the new Lewis 0.7 and have it on a project where it was able to overcome a number of challenges.

The project ran very smoothly with the quotation being issued in April 2017 and after a number of correspondence to and fro an order was placed in late July with the sheets delivered to site the following week.

20170901_122808  20170908_150742

The sheets were laid in just a couple of days and the concrete screed was pumped in and leveled in a single day. All to plan and allowed the build programme to be maintained if not slightly improved on.

Contractor: Godfrey & Hicks, Fordham

Location: Cambridgeshire

Area: 150m2

Product: Lewis Deck 0.7 Gauge

 

FAQs

Ask CDI a Question

  • Q

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

    A

    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.

    Q

    Do you fix Lewis Deck down to the joists?

    A

    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.

    Q

    Lacomet – How come it has no scrap value?

    A

    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.

  • Q

    Do you fix Lewis Deck down to the joists?

    A

    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.

    Q

    Lacomet – How come it has no scrap value?

    A

    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.

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