a couple of grout questions

[notoriouseddie]

Hi all,

Recently had my bathroom refurbished and delighted with the finished result.

I've noticed the grout in the shower areas goes darker when it gets wet but then returns to normal when it dries. I asked my tiler if the grout needs sealed and he seemed confident it didnt

Is this the case? Or should I be looking in to get the grout protected from water penetration?

Secondly, the grout on the floor is almost sandy in texture which means its picking up dirt and stains quite readily. Is it possible to sand down grout afterwards to make a smooth finish?

It was first grouted with the same stuff on the walls but quickly discoloured and became unsightly as dust got into the bathroom before the grout had fully dried so has been redone with a grout/epoxy mix

 

[Richard C]

I've noticed the grout in the shower areas goes darker when it gets wet but then returns to normal when it dries. I asked my tiler if the grout needs sealed and he seemed confident it didn’t. Is this the case? Or should I be looking in to get the grout protected from water penetration?

Unless it's an expensive epoxy based product, waterproof adhesive/grout is only waterproof in the sense it won’t disintegrate when wet, it’s still permeable. For this reason, it’s important that your tile base is waterproof. Plasterboard should be tanked in wet areas, if moisture gets through it will turn to mush (even MR eventually); this is probably the single biggest cause of early tile failure. It’s always best to use waterproof tile backer boards. If you use the correct tile base, sealing isn’t normally necessary but weather or not you seal it now depends on your answer to the above; if you do, leave the shower to dry for several days to avoid sealing in moisture.

Secondly, the grout on the floor is almost sandy in texture which means its picking up dirt and stains quite readily. Is it possible to sand down grout afterwards to make a smooth finish? It was first grouted with the same stuff on the walls but quickly discoloured and became unsightly as dust got into the bathroom before the grout had fully dried so has been redone with a grout/epoxy mix

Sanding will make no difference, only thing you can do is seal it after cleaning; what colour grout did you use? White or light colour grout on floors is never a good choice; it starts to look very grubby after a relatively short time.