Natural Stone Sealing


Natural stones like sandstone, marble, granite, etc. are often used in interior and exterior floors and facades, bathrooms and swimming pools. Natural stones are porous materials: they contain a network of capillary channels in which fluid substances can penetrate.

If fluid substances (like silicone oil or plasticizers) penetrate into the stone by these channels, this can cause staining. This staining can be in some cases long-lasting and impossible to remove.

In order to prevent staining, specific sealants should be used on natural stone. The silicone or hybrid sealants suited for these applications contain a specific plasticizer that cannot migrate out of the sealant. Some sealants even contain no silicone plasticizer/ silicone oil at all. Soudal offers specific sealants suited for use in combination with natural stone. E.g. Silirub MAFix ALL® FlexiSoudaseal 240 FC and many more.

International Standard Tests

There is an ISO (international standard) test for testing staining on natural stone: ISO 16938-1. This is the more critical test, ‘with compression’. ISO 16938-2 is the same test without compression. If a sealant passes the test it can claim to be non-staining on a specific type of natural stone.

We tested several of our sealants on Carrara marble and (Belgian) Blue stone, which are common and well known natural stones. For products specifically intended for use in contact with natural stone, this standard is also mentioned in the Technical Data Sheet: ‘Tested according to ISO 16938-1 (Testing for staining on natural stone by sealants). Silirub MA, Fix All Flexi and Soudaseal 240 FC are all tested according to this standard.

Fix ALL Flexi White 290ml
Hybrid polymer sealant adhesive
Silirub MA Marble grey 300ml
Neutral cure natural stone silicone sealant