Tiling Straight and True
Part of the preparation process is to check that the surface is straight and true. To test this you will require a 2 metre straight edge with a 3mm spacer at both ends. This should be placed on the various wall or floor surfaces, in all directions. The surface is deemed 'straight and true if there are gaps no greater than 6mm under any point of the straight edge and that the surface does not touch the straight edge at any point.If you discover gaps larger than this, floors will need leveling and walls will require pre smoothing with a suitable tile adhesive. This type of remedial work is particularly difficult to carry out on walls and it is normally best to strip off uneven walls and start again.
If you tile on a surface that is not straight and true it may result in tiles lipping, uneven joint widths, uneven surfaces or adhesion failure caused by an excessive thickness of adhesive.
Gap under straight edge is never greater than 6mm or less than 0mm therefore floor or wall would be considered straight and true (diagram greatly exaggerated)
Gap under straight edge is greater than 6mm or less than 0mm therefore floor or wall would NOT be considered straight and true (diagram greatly exaggerated)
