CONCRETE & STONEWORK
POINTING / GROUTING / JOINTING EXTERNAL PORCELAIN TILE PAVING
The key to the successful jointing of external porcelain paving is to use an equally high-performance jointing material , and one which is easy to apply and to remove and clean residual jointing material from the porcelain surfaces . Traditionally , cement-based tile grouts are used for porcelain tiles on internal walls and floors which is fine , but for external porcelain paving , these cement and so-called ‘ hybrid ’ ( means cement with a bit of polymer added ), tile grouts are sufficiently durable for long term external exposure to weathering - Great inside , but not outside . There is also the issue when outside exposed to direct sun , that dense , impermeable products such as porcelain , have limited adhesion to cement mortars , and so shrinkage cracking and debonding due to normal thermal movement is highly likely in the joints – the last place you want to see cracks is in your porcelain paving .
Cement-based pointing products today are polymer modified to counteract cement shrinkage , but this makes them very sensitive to any residual water in the joints that will negate any claimed low shrinkage figures on the product data sheets ( an old concrete technology joke – lab-crete versus site-crete ), this concern , together with the limited adhesion to dense porcelain , and the fact that these problems are more likely in smaller joints , such as the typical 3-6mm for porcelain , this is obviously a concern . Cement products are also difficult to remove from porcelain surfaces after finishing , usually involving additional cleaning and treatments to remove the ‘ cementhaze ’.
The best solution for porcelain paving jointing is not an internal tile grout , but a high performance , 2-part , epoxy resin bound , graded fine alluvial sand based jointing system .
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