Tiled Floor in Bathroom Wet Area

[hubbysadiyer]

Hi, am a newbie on this site but we have a problem in our bathroom which I'm hoping someone can help with.
My husband is a very competent DIYer (renovated & extended 2 properties) but a couple of years ago he made a wet area for a walk-in shower which has now got a discoloured/mouldy floor.
The floor was concrete (left to dry for several weeks), he put the proper tanking membrane etc down & up the walls, following instructions correctly.
Then tiled with light coloured mosaic sandstone tiles on the floor, they came in sheets with a mesh backing (the walls were tiled with large ceramic tiles), he used the correct tile adhesive & separate grout as recommended by a respected tile shop in our town.
He then sealed the floor several times with the correct sealant for natural tiles.
There is a shower fan/light over the area which is used whenever the shower is used (usually twice a day), there are 2 radiators in the bathroom which are on in the winter from about 6am to 9pm, but not on in the summer.
Over time the tiles have discoloured to quite a dark shade where the water hits them & there is black mould on the floor, even though it is cleaned regularly. There is no mould on the walls.
Can anyone suggest what we can do please?

 

[tictic]

the floor tiles should be cleaned...stripped of any sealer then re-sealed at least once a year, if its a hard water area and used regurarly.

look into products like abra clean..or nano scrub..(dont know if still about maybe ebay/amazon)..
or look into ltp/lithofin/universal/fila products for tile restoration products.

 

[hubbysadiyer]

Thanks, will try restripping.
If it doesn't work would we be able to tile over the sandstone mosaics or would it be better to remove them completely & then retile, this time using a ceramic tile.

 

[tictic]

look into the lithofin MN range....

grimex then the stainstop range this should bring your tiles back to origanal...

 

[hubbysadiyer]

Thanks, will look into the products recommended. Hope they work as we like the tiles!

 

[hubbysadiyer]

Just in case we can't remove the black mould completely, would we be able to retile over the existing tiles on the shower area floor or do we have to remove them first?

 

[tpt]

yes you would be able to tile over them.
but the products mentioned above should make light work of your problem.