Our Systems Archives - CDI

Lewis Deck

LEWIS Dovetailed metal decking, as part of a joisted floor system, provides a first class solution where acoustics and fire protection are key concerns.

The Lewis system works very well with screeded underfloor heating and cooling systems, allowing them to work more efficiently than without the sheets in place.

LEWIS provides a number of solutions for renovations and conversions as well as with new build projects using all types of build including traditional, timber or steel frame as well as new methods of build such as ICF and modular off site construction and mezzanine floors.

Apart from standard domestic separating floors, LEWIS provides exceptional solutions for bespoke acoustic floors within live music venues, night clubs, restaurants, recording studios, recreational performance studios, specialist test labs, plant rooms and many other commercial applications.

Lewis Deck
Lewis Dovetailed sheets

Please take a look at our current LEWIS brochure for further information.

Lewis Deck Brochure

Please see the leaflet below providing the recommended method of installation. Detailed instructions are given on the laying, jointing and fixing of the sheets, types of screed and concrete. Additional technical advice is available on request.

LEWIS fixing and installation

  • High performance acoustic floors
  • Underfloor heating in suspended floors (only 52mm thick)
  • Works on any type of beam or joist
  • High loadbearing capacity
  • Low dead loads
  • Thin overall thicknesses (generally 50mm, but from 36mm to 75mm)
  • Simple and easy to install
  • Fire ratings up to 120 minutes
  • New build or renovation/ conversion
  • Suitable for liquid screeds and fine grade concrete
  • Suitable for use with ceramic or stone tiles
  • Great for wet rooms
  • Span joists (up to 2.5m centre to centre) or lay direct to existing floor
  • CAD drawings and BIM models available

The production facility is ISO9001 certificated and the Lewis system is fully tested and carries a number of certifications which can be found in our “Support” section of the website.



Op-deck is a lightweight insulated floor and roof system. The advantages of composite metal deck concrete floors and traditional rib floors have been combined in this unique patented floor/ roof system.

This insulated concrete floor/ roof system (ICF) is based on traditional concrete installation but with optimal design and installation flexibility.

It is suited to insulated, high-load-bearing applications including car park roofs, intensive green-roofs and suspended high load floors including supermarkets, hospitals, etc.

An Op-deck system can be laid on supporting structures of steel, concrete, brickwork, wood, etc. The Op-deck sandwich floor panels function as permanent shuttering for a relatively thin reinforced concrete floor with a free span of up to 10 metres maximum.

Op-deck comprises a sandwich panel made from thin profiled steel sheets with PIR foam insulation. EPS profile blocks on the sandwich panel ensure further weight reduction and turn the floor into a concrete floor of the T-beam principle (concrete rib floor).

Both components, the sandwich panels and the EPS profile blocks are installed on site. The result, after the reinforcement and concrete have been applied, is a lightweight insulated concrete floor with a large free span, small constructional height and a smooth white (RAL 9002) underside of flat sheeting, which functions as a ceiling. It is possible to include under floor heating or a complete energy management system in the Op-Deck insulated concrete floor.

Op-Deck Insulated Roof System

The Op-Deck System:

  • Thickness of finished concrete floor from 250 mm.
  • Low own weight (from 190 kg/m2).
  • Free span up to 10m.
  • High permissible load (Prep).
  • High bearing capacity at point load (Prep).
  • Flexible system construction.
  • Fire-resistant (Resistance to Fire Penetration and Fire Transfer) = 60 minutes.
  • Insulating floor (Rc > 4 [m2.K/W]).
  • Strut-free installation (max. 5.5m).
  • Simple and fast installation.
  • Easy logistics at the building site.

Op-deck sandwich floor panels and the EPS profile blocks are simple to process. An installation procedure is available. Optionally specialized application companies are available to install the Op-deck insulated concrete floors.

CDI OP-Deck Brochure

If you have any questions regarding the system please contact our technical team.



Hody profiled steel sheets have a modified trapezium shaped profile of 60 mm in height and intended for constructing, so-called, ‘low’ composite steel decking.

The finished concrete floor is between 110 mm – 290 mm high and Hody trapezium sheets can be used on free spans of up to 8 metres over the bearing construction.

Hody composite steel decking consists of a specially rolled trapezium-shaped steel sheet which functions as permanent shuttering for the relatively thin and lightweight concrete floor. This provides an extremely strong, stable and fire resistant structural floor construction which is very cost effective.

During the curing process of the concrete the trapezium sheets act as the shuttering that transfers the weight of the concrete and the assembly load to the bearing construction. When the concrete is fully cured the Hody sheets, often with supplementary reinforcement, create a well engineered structural floor solution. The sheets can be provided with interior (KID) polyester or PVDF coatings in RAL colours on the underside.

CDI Hody Leaflet

Hody 60 UK Design leaflet CDI

HODY Assembly Manual

The sheets profile has a modified geometry which allows for an optimal pouring load and makes sure the combination of the sheets and the concrete allows for the highest possible load bearing capability of the floor.

The sheets have been successfully installed on new build structures, renovations, ground floor and upper levels, mezzanine floors, walkways, cantilevers as well as heavy civil projects such as bridges.

Popular uses:

  • Conversions and renovation of existing properties
  • Mezzanine floors
  • IFD Projects
  • Bridges
  • Modulair building
  • Sustainable constructions
  • Ground floors and structural floors
  • Raised floors
  • Overhanging floors
  • Permanent shuttering
  • Industrial, Flexible and Demountable (IFD) Building projects

Max 4

Max4 reinforcing sheets provide a great solution for leveling uneven existing floors with the introduction of reinforced ultra thin light weight liquid screed floors in projects where weights and height restrictions are an issue.

The Max4 reinforcing sheets are manufactured from 2 sheets of special profiles steel and designed for use on existing timber or concrete floors where an extremely thin liquid screed solution is required.

The system is extremely easy to install and the twin profile sheets allow for underfloor heating pipes to be threaded through to create a very thin underfloor heating system. By using a very high specification 5 layer oxygen barrier it ensures that the system is in accordance with DIN4726. The heating pipes are connected to a standard underfloor heating system using 2 and 4 port manifolds. With the shallow depth it ensures a rapid heat up and optimal heat spread.

By having a thin concrete feel to the floor it allows the use of thick tiles or natural stone floor finishes on a timber floor.

Max4 without UFH
Max4 in a roof space

The acoustic performance of an existing floor can be considerably improved with the introduction of a “Fonofive” acoustic mat under a Max4 floating floor. This matting is made up of a 1.5mm layer of acoustic insulation and also a 4.5mm thick layer of non-woven polyester.

Properties of Max4:

  • Extremely low weight but with high load bearing capabilities
  • Extremely low final floor thickness
  • Self leveling reinforced floor covering
  • Non flammable
  • Acoustic floor benefits
  • Ideal for wet or electric under floor heating systems

Max4 leaflet

Detailed fixing instructions are available on request and on-site installation advice can be provided by one of our technical advisers. For larger projects we have experienced teams that can provide supply and installation prices.

For extensive guidance and advice please contact our team. Details can be found on our “Contact Us” page.


FastSlab Foundation

The FastSlab Foundation System is a fast track method to construct foundations and ground floors, ideal for sites with limited access, poor ground conditions, flood plain locations and areas with tree root issues. It also works equally well in all ground conditions whilst eliminating a sometimes difficult and expensive muck shift. A typical FastSlab house foundation system can be installed within one week and is ideal for all forms of timber, LGS frame, SIPS or modular building systems.

The FastSlab foundation system uses helical steel screw piles, a LGS ring-beam, steel internal I beams, interlocking grey EPS insulation blocks and Lewis Decking for the foundation and ground floor structure. On top of this is then fitted a timber soleplate ready for the walls of the building. All this can be fitted very quickly meaning that the duration of the foundation & ground floor slab element of the build can be drastically speeded up and as such reduce costs on a project.

The geoLOGIC screw piles have a capability to carry significant loads at shallow depths to support a galvanised lattice beam ring beam, galvanised floor beams and large format EPS insulation and Lewis Deck composite floor slab. The ground floor is fully insulated and U Values of 0.16/ 0.17 are standard within the floor but can be improved to achieve 0.13 or better if required. The galvanised lattice ring beams are all manufactured to specific dimensions to eliminate waste and the standard length FastSlab floor beams are easily cut to length on site.

Floor insulation is taken care of by tightly fitting FastSlab EPS insulation blocks that sit snugly between the floor beams creating a thermally efficient sub floor ready to accept the DPM, Lewis Deck and screed. The weight of the FastSlab floor system is only a fraction of alternative PCC Block and Beam systems and can be installed without any heavy lifting equipment.

FastSlab Foundation Literature

  • Works with all ground conditions
  • Cost effective
  • No heavy lifting equipment needed
  • Fast & easy to install
  • Reduces time on site
  • High thermal performance
  • Efficient underfloor heating system
  • No excavation


The FastSlab Ground Floor system is designed to make it quick and easy to replace existing suspended ground floors with an insulated concrete or screeded floor. This gives the solid feel of a concrete ground floor with the benefit of maintaining the ventilated void beneath to prevent moisture issues in the existing walls.

The FastSlab system is a unique combination of the Dutch VBI PS ground floor renovation system and the Lewis Deck metal dovetailed sheet.

The PS renovation floor system is a patented innovation from VBI and is a lightweight altrenative to block and beam floors. The unique feature of the “FastSlab” system is the use of galvanised steel joists that weigh only a fraction of pre-cast concrete beams. Joists are supplied in standard lengths and can be very easily cut on site. The tight fitting EPS insulation blocks are available in 2 thermal performance values (0.23 W/m2K and 0.20 W/m2K) and sit between the galvanised beams creating a robust and thermally efficient sub floor ready to accept the finished slab.

Both the beams and the infill blocks are light and easy to handle making the installation in renovation and conversion projects, as well as new build, so much easier than if using concrete beam and block.

The use of Lewis Deck on top of the PS system removes the need for a reinforced concrete slab needing to be added to the system. This reduces the overall depth of the screed to 50mm as well as reducing the weight without compromising the load bearing capability. It also allows the addition of a very efficient underfloor heating system within the floor zone.

FastSlab Ground Floor system

  • Safe and easy to install
  • No heavy lifting needed
  • Efficient underfloor system if required
  • Very fast installation
  • Maintains void underneath
  • Long life span
  • Low dead weight/ high load bearing capability

Please contact us should you require any further information regarding the FastSlab Ground Floor system.

Lewis SteelFrame Concrete Floor (SCF) system

The LEWIS® Steel Frame Concrete Floor (SCF) is a patented self-supporting floor system.

The floor system features prefabricated elements consisting of a closed steel frame of cold formed C-sections that have been cast into a reinforced concrete shell, this concrete shell also forms the ceiling slab for the floor system.
The steel frame features round openings so that pipes and installations can easily be incorporated into the floor. A LEWIS® Deck top floor is placed on the steel frame. Several removable floor zones can be incorporated into the top floor depending on the level of flexibility needed in the floor system.
The LEWIS® Steel Frame Concrete Floor makes it possible to achieve free spans up to approx. 15 meters.
In addition to being used as an intermediate floor, the floor system can also be used as an insulated ground floor.

Lewis SCF system installation
Lewis Steel Concrete Floor system installation with a crane

Top floor

A LEWIS® Deck floor is used as the sub-floor on top of the floor elements. This sub-floor allows for high live and concentrated loads and gives the feeling of a solid concrete floor. The LEWIS® Deck floor can be completed with a cementitious or gypsum-based screed.
For an optimal indoor climate in the building, it is possible to integrate underfloor heating into the LEWIS® Deck sub-floor. Depending on the intended purpose of the building, a completely dry floor finish can be utilised on floor elements. This floor can, for example, be made of cementitious board material.  A dry top floor is also the solution when 100% flexibility of the building is required within a short operating period due to a change of function or disassembly.

Lightweight floor construction

Foundation-related costs can be reduced in new-build projects because the LEWIS® Steel Frame Concrete Floor is very light. The low weight also makes the floor system very suitable for renovating building on existing foundations.

Lewis SCF in a conversion project
Lewis Steelframe Concrete Floor system in a conversion project

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Our Systems Archives - CDI