01480 215 000


Commercial Clayboard

Technically sound void formers

Commercial Clayboard® is an industry leading void former that is the solution of choice for structural engineers, specifiers and architects across the UK and beyond. Refined over almost half a century by some of the smartest minds in our industry, it is truly unique in its design and manufacture.

Our void former system protects against the potential damage caused by clay heave and ground movement and leaves a technically sound space.

It is made from the finest 100% recyclable paper honeycomb core that has been set between polypropylene facings. This lightweight void former is strong enough to support the weight of wet concrete, as well as steel re-inforcements. Once water is introduced, it has the effect of switching off the honeycomb’s compressive strength, leaving a reliable void.

This space can be relied on to accommodate clay expansion, without exerting undue pressure on the structure above. It successfully results in a void that can accommodate natural soil shrinkage and expansion that occurs with time.

Every delivery of Commercial Clayboard® comes with easy to follow installation guidelines and is delivered to site in a weatherproofed shell, protecting it against the elements and ensuring it’s in the best possible condition during storage. We can also provide an additional wrapping service for individual boards, which can be helpful once the pallet arrives on site. Our specialist team of consultants are also always on hand to support and facilitate the easy installation of our products in person where needed.

Benefits for you

  • All clients have a dedicated account manager with many years of experience working with even the most complex commercial projects
  • Commercial Clayboard® has a nominal compressive strength of 90kN/m2 when dry
  • It has been specifically designed to work for larger scale commercial projects as a cost-effective and reliable solution on short lead times
  • It is available in four different thicknesses and can be adapted to best suit a project’s shrinkage levels without the need to calculate safe and fail loads
  • It is lightweight and arrives on site in a weatherproof seal with easy to follow installation guidelines
  • It is a sustainable and environmentally friendly in its design and manufacture
  • Thinner product reduces land excavation costs and muck away costs, this can be very significant on large commercial sites
  • Install on a sand blinding rather than concrete reduces ground prep costs

Key Commercial Clayboard® Information


Commercial Clayboard® is supplied in panels 2440mm long by 1000mm wide, by the specified thickness. It is delivered to site in good time on lightweight pads for easy unloading, and is polythene wrapped for protection against the weather.


The thickness required will be determined by the plasticity index, specified by the soil engineer. Varying thicknesses are available and a member of the Clayboard team will be able to advise you on the best possible solution.

Clayboard 2_Sizes
Compressive strength

Commercial Clayboard® (KN90) has a nominal compressive strength of 90kN/m2 when dry and is designed to support the weight of wet concrete up to and over 1m thick. When the core is made wet, KN90 Clayboard will collapse under nominal compressive load of approximately 3kN/m2.

Additional Items

All of our Clayboard boards can be supplied pre-wrapped to site so they are ready to be laid with water protection. Our VoidPak Pipe system can be used in conjunction with Clayboard to effectively and easily introduce water to the Clayboard and start the honeycomb degeneration process.

Get In Touch

To speak with a member of our team about your Commercial Clayboard® requirements, simply get in touch by calling us on 01480 215000 or by emailing clayboard@dufaylite.com.


I used Clayboard for the first time on a residential site last month. After ordering with Trisha from Travis Perkins, I was very impressed as the void former was on site in a few days. I have used other ground heave solutions before but none of them had delivered a true void, so I wanted to make sure I installed the product correctly. I had a quick look over the installation guidelines over a cuppa and I discovered the product was very easy to install. The product is lightweight and the fact it comes on weatherproofed pallets, makes my job easier when it arrives on site.

Groundworker, London

We like to deal with the market leading product manufacturers and the fact that we have been stocking and distributing Clayboard for as long as we have is testament to our relationship with Dufaylite. We always maintain healthy stocks of Clayboard, but there will be times when we need support from Dufaylite with a speedy replenishment. They are also quick to respond to quotation requests or questions about the product from our groundworks customers.

Tim Stubbs, Lemon Groundworks Solutions

I started to work with Clayboard on a number of sites about five years ago. I had been aware of other ground heave solutions previously, however after reading about the benefits of Clayboard on the website and getting to know Nigel at Clayboard, I realised Clayboard delivered numerous life cycle benefits to a project, plus it is technically a true void former.

I am often in contact with Nigel. He is reliable and extremely knowledgable of the product and the industry. Clayboard is competitively priced allowing the site to retain the cost benefits from less land excavation and ground prep, the level of service I receive from the team at Clayboard, the technical support of the product and the fast delivery times to site, help to ensure the site maintains its tight schedule.

Architect, Manchester

Find out More

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Our Products


Wrapping Solutions

waterproof tape

Waterproof Tape


VoidPak Systems


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Commercial Clayboard


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