Tests are an essential part of the TWEHA concept. Our bonding systems are subjected to an intensive internal test program with conditions much heavier than normal use. Please have a look at our survey of tested and approved cladding materials.

Because the reliance in proper functioning of our products is very important, for many years we also have been asking various independent external experts to judge our bonding systems, so by globally executed test programs the excellent quality of the TWEHA glue systems is confirmed.


Another point of attention is moisture or water. If the slab is soaked with water the adhesive will not adhere to the surface.

Due to the occurring stress on the surface at the moment of application of the glue bead, a water film will occur between the natural stone slab and the glue bead which ultimately will block the adhesion of the adhesive bead on the natural stone (please have a look at this).

The advice is therefore to store the natural stone on a dry place (not in the rain) in order to make it possible to dry the natural stone slabs and thus to achieve a problem-free glued connection.
Of course this item is not applicable on natural stone only! It matters on all cladding material!


‘Surfaces to be bond must be dry, clean and free of grease’ as stated in the Instruction For Use on behalf of TWEHA products.

A ‘wet-saw’ cutting system will account for probably 95% or more of the cuts on most natural stone veneer or slabs. This wet saw cutting system works on the concept of water being applied to the blade and to the tile or slab of natural stone to provide lubrication, cooling and rinsing as the blade cuts through.

The sediment that arises when sawing natural stone, is usually partly found as dust on the back of the plate (front is processed, so this sediment has disappeared on the front of the plate).

The bonding on this layer of dust or sediment will not be successful because this sediment adheres only loosely to the surface of the natural stone and then manifests itself as a layer of dust between the natural stone slab and the adhesive bead and thus frustrates the adhesion of the adhesive on the natural stone.

So in case this layer of sediment or dust occurs, wipe it off with a brush before applying your adhesive!



Facades are designed and executed with the aim of realizing a specific and intended expression or image. An expression that can be properly nullified by pollution and unfortunately bonded facades often pollute unnecessarily if unknowingly decided to use an extra hook or screw.

Luckily it is not as common as it once was because it is considered as unnecessary and also in conflict with the contemporary safety philosophy as internationally used in static regulations. There’s a reason why people use the term ‘panic hook’ when such a discussion heat up due to ignorance.

Given the above, it is important that the intended appearance of your business premises is maintained. After all, it is the gateway to your company or product.

Therefore it’s necessary to design and build your façade in such a way that atmospheric pollution, acid rain and exhaust fumes cannot affect the image that your façade must project.

Consistent with poor detailing pollution will lead to an impression of sloppy and deterioration.


The care and conservation of the environment has always been one of TWEHA’s major concerns. Sustaining our lifestyle and the crucial environmental balance that this implies requires specific policies and tangible actions.

TWEHA has always been well ahead of market trends in this area, and for more than 25 years has been implementing improvements to its production systems, aimed at minimising their impact on the environment.

TWEHA’s environmental strategy goes far beyond the optimisation of production systems; indeed, our efforts are also centred on the introduction of products and packaging that contribute to the reduction of enviromental impact