What is bowing?
Porcelain paving is an amazing product and has many benefits although it does come with one downfall. Due to the way porcelain paving is produced the heating and cooling process causes the edge of the tiles to bow slightly. Whilst manufacturers do everything they can to reduce bowing it is just something that cannot be avoided. This applies to all porcelain paving but becomes more apparent on the larger format tiles. When tiles are bowed lipping can occur. Lipping is basically the difference in height of installed tiles. Which is sometimes unsightly and can pose a tripping hazard.
Throughout europe ISO 10545.2 is the standard for dimensions on porcelain tiles. The ISO required value for bowing / warpage is ± 0.5%. This means on a larger 1200x600mm porcelain tile the bowing can be upto 6mm and still conform to the correct standards. Whilst most manufacturers have higher standards than the ISO standards and this amount of bowing would be very rare, installing a tile with bowing on this scale is still achievable. Following the correct installation of course.
Tips to avoid lipping
Ensure sub base / hardcore below area to be paved is level.
Ensure all tools are clean from debris.
Use the correct joint thickness. We recommend using a 5mm joint. Anything narrower can make any differences between the tiles more prominent.
Lay tiles in a 30%, 25% or square bond. On the larger 1200x600 / plank size tiles 30% bond is the maximum we would recommend due to the nature of the tile. 
The best way to avoid lipping is by using a leveling system. We sell and recommend with every purchase of porcelain the Raimondi RLS leveling system which can be viewed HERE. The system is made up of simple clips and caps. The clips are installed under the tile and the caps are screwed down into position. Once the caps are screwed down tight they even out any difference in levels between adjacent tiles. This removes any lippage before the mortar / adhesive sets. Once the adhesive has set the caps can be removed leaving you with a level and lippage free area.
To see the process behind the RLS Leveling system please take a look at the video below:
In summary bowing and lipping can be worked around when the correct installation methods are followed. If you need any more help or advice please don't hesitate to get in touch with us. Our phone number is : 0161 430 5390 or email us : sales@pcrsol.co.uk