How do rubber tiles change over time?

Rubber tiles made from PU-bound rubber granules change over time in colour and surface appearance, with the extent depending on the type of granules, sun exposure at the installation site and use of the area. Their elastic properties change more slowly than their appearance. Patio tiles also go through an initial settling period during the first few weeks. On tiles made from coloured recycled tyre rubber granules (ELT), the pigmented PU binder initially darkens slightly in sunlight; as individual patio tiles receive different amounts of light, the surface may look uneven for a time. A freshly cut EPDM wearing layer takes on a slightly warmer tone during its first days in the sun.

This temporary colour change can make a patio slab appear darker in sunlight. It is caused by the PU binder rather than the EPDM granules, is reversible and subsequently lightens again, after which the appearance will generally even out. On UV-stabilised patio tiles, the effect of UV radiation is delayed; this is unrelated to the colour shade and is not a promise that the colour will remain unchanged. Over the longer term, the colour appearance changes for different reasons according to the type of rubber granules.

For tiles made from naturally black ELT rubber granules, the deep black colour when new gradually becomes anthracite under UV exposure, similar to the colour change seen on car tyres. In coloured ELT tiles, the PU binder is pigmented and forms a coloured coating around the black rubber granules. The colour is in this coating, not in the granule itself; in areas subject to foot traffic, use can wear away the coating and reveal the black rubber granules beneath. An EPDM wearing layer is coloured throughout, colour-stable and UV-resistant.

Deposits can also alter the appearance. Dust, pollen and fine sand can settle into the surface structure, making the area appear duller, but these residues can be removed and the slip resistance is retained. This should be distinguished from the long-term behaviour of pure ELT under continued intense sunlight: it slowly loses elasticity and becomes more brittle near the surface, a process that is slower than the visible colour changes.