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.

"Max4 allowed me to strengthen the bathroom floor I was upgrading without needing to rip up the old floor boards. It also gave me the solid floor I was wanting without restricting the head room issue that I had in the room".

Terry Grant

Max4 is an ultra-thin solution to improving the feel of wooden floors, but also at the same time limiting the necessary build-up.

The standard Max4 sheets are just 10mm thick and once screeded (including the underfloor heating) produce a system that is just 15mm in depth.


There is also an option for a 20mm thick sheet that provides options for other diameter pipes.

The standard 10mm Max4 will be capable of 90-100W/m2 of heat output, limited only by the maximum allowed surface temperature of 29 degrees Celsius.

It is also possible to upgrade the system acoustically with the addition of the Max4 acoustic mat, this adds less than 6mm to the floor depth.  The system can achieve compliance with Building Regulations part E – the passage of sound between dwellings.

Max4 is especially useful within Listed Buildings as it is a floor overlay system that does not damage the existing floor structure and, due to the low build-up, allows for floor to ceiling heights and room proportions to be maintained.  Example projects are available on request.


Ask CDI a Question

  • Q

    What are the Lewis Deck sheet sizes?


    Q: What sheet sizes are held in stock for delivery within a few days after order?A: We stock 2500mm and 1300mm sheets.  These are all 630mm wide and 16mm deep.  Deliveries are made via the pallet network directly to site.  The smaller sheets are aimed at small bathroom renovation projects and can be supplied in small numbers via TNT.2.5* and 1.3m sheets allow for the 100mm overlap to occur over a joist, with joist centres being either 300mm, 400mm, 600mm, 800mm*, 1200mm and 2400mm*. (*2.5m sheet only)For larger projects we are able to produce bespoke sheet sizes if required, please get in contact to discuss other options for sheet sizes.


    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.

  • Q

    Why don't my Lewis sheets interlock like they do in the video?


    Q: Why don't my sheets interlock like they do in the video?A: The sheets have two sides (one printed, one plain), the dovetails on either side are different widths, it is then necessary to alternate the sheets print up and then print down.


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