Step One – Surface Preperation
The first step is to remove the loose / ageing grout. To do this we first spray the grouting liberally with a lime scale removing cleaning product (In this case Cilit Bang) and leave it to sit for about 15 minutes (about 3 times the time recommended for the normal use of this product)
Now we scrub the grouting vigorously with a large scrubbing brush and rinse down thoroughly with clean water. This removes any loose grout and cleans up what remains. At this point it becomes clear that the mosaic tiling of the bathroom ids actually large tiles with grooves moulded in them which are then filled with grout to give the appearance of a mosaic. This is obviously a lot easier to install than a real mosaic and looks really good once the grout is in place.
Next we let the wetted surfaces dry thoroughly overnight.
Step Two – Apply Grout
Now we are going to apply the new grout. This needs to be mixed thoroughly with water in a suitable recipient following the maker’s instructions. Typically 3 parts grout (or white cement) to one part water. You will probably need somewhere between 1 and 2 kg to re-grout a shower booth.
We apply the grout generously to the tiles making sure we more than fill all the grooves with grout. You should only apply grout to about 1 square metre at a time. Then we remove the excess with the rubber float. Note: The float should always be moved in a diagonal direction in order to leave the channels between the mosaic tiles filled by grout. Repeat this process until the entire shower booth has been grouted.
Next we take a dampened sponge or cloth and gently wipe along the lines of grout to give a nice u shape profile between the tiles. We now leave everything to fully dry for about 8 hours,
As the grout dries it will leave a slight haze on the tiles. This haze can be removed by buffing the tiles with a rough, clean rag once it is dry (minimum eight hours – according to manufacturer’s instructions). Don’t worry if there is areas where excess grout has remained stuck to the tiles, this is a pretty common occurrence – especially if it’s your first attempt at grouting and can be easily remedied.
Step 3 – Remove any excess grout and polish the tiles
How to remove any excess grout from porcelain tiles
The next day we can proceed to remove any excess grout which was inadvertently left stuck to the tiles (don’t worry there always seems to be some that you overlook and it’s easy to fix).
I’ve heard of people using mild acids or vinegar solutions to do this. Personally I’ve had great success using a scotchbrite green plastic scourers backed by an off cut of plywood to clean the grout off using the same lime scale cleaner that I used at the start of this process. Just apply a little of the cleaner to the tiles than scrub gently in a circular motion till the excess grout is removed and rinse thoroughly with water. Hey presto a total of about 4 hours work (spread over 3 days) and the shower room looks like new !