I visited this property on the outskirts of Kidderminster which had Porcelain tiles laid throughout the downstairs. The owner was happy with the tiles but unhappy with the grout which had become stained. This is not unusual as Porcelain tiles are very resilient but the cementous top layer of grout is slightly porous and can attract dirt. As a result, the grout can become discoloured over time and if it becomes very stained no amount of cleaning will bring the grout back to its original
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Cleaning Tile 