For many years TWEHA advises to omit the use of joint profiles in combination with more or less porous materials, such as natural stone or cement fiber panels.
Despite our advice and experience, a joint profile still seems to be applied regularly.
There will be capillary action or suction of (rain)water in the narrow space between the cladding and joint profile. As a result of which the porous façade sheets will continually come into contact with water and at long last will fill up with small amounts of water.
Resulting in fungal growth, green deposits and crumbling edges are the result.
The use of a joint profile is a cause for this phenomenon. A knowledgeable installer knows that the application of a joint profile must be avoided and therefore will strongly advise you to omit the application of a joint profile