Picture Framing on Stone

Picture Framing on Stone :Tread with Caution:

These photo are typical situations where picture framing due to trapped moisture are often blamed on poor sealer performance. One of the major features of all Aqua Mix penetrating sealers is good vapour transmission. Therefore it is very rare for a sealer to cause this type of problem. In most cases (as it is on this job) the moisture is trapped by the uneven application of the adhesive. Perhaps the most well know cases are where adhesive is applied using a spot fixing technique.   However it is usually not just how the adhesive is applied but also other things such as insufficient falls or falls in the wrong direction, lack of a waterproof membrane or vapour barrier. In some instances clients will understand all of the above but still try and blame the sealer because they believe the sealer is waterproof and that moisture can only come from rain or other external sources. This is obviously wrong as no sealer is waterproof and sources of water can be internal such as the water table as well as water that condenses inside the tiled system. I have long been an advocate of specifying sealers along with a complete system of proper membranes, adhesives, sealants and grouts that all manage the amount of water that moves in and out of a  tiled installation. The photos show areas of brown to yellow discolouration – the blooming effect is most likely a soluble mineral (most likely pyrite) that has been set off by the water. This is just another example of why you need to manage and minimise the amount of water that enters the installation. In summary Tread with Caution when asked to evaluate these types of issues because in most cases it will have nothing to do with the sealer

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