Forza is right, it's a different plaster and how it's applied is a specialist task. I'm having tadelakt done next month which is similar. Normal plaster will be applied once the tiles are removed (to get rid of any blemishes). Once dry a thin layer of tadelakt is then applied. Then it needs 3 lots of waxing to get the polished look so it's very labour intensive.

i will try and find the pics as I've seen normal plaster used and just sealed. It took me quite a long time to find a tadelak/polished plasterer specialist and tbh was about to give up and try this! I wouldn't have used it in the actual shower though!

Here's the story showing normal plaster being used

https://www.houzz.co.uk/magazine/houzz-tour-a-converted-victorian-dairy-with-a-magical-courtyard-stsetivw-vs~115062014?irs=US

Tadelakt, microcement. Expensive and 100% waterproof is never guaranteed.

I have extensive experience with polished plaster and there are cheap Italian variants, however they often fail after a short period of time and hey require someone who knows what they are doing to apply them properly.

The king of polished plaster manufacturers, in my humble opinion, is a British company called Armourcoat who also provide the details of professional installation teams. The problem from your point of view is not whether it can be done, but how much will it cost to do properly. The answer is that Armourcoat is not a cheap product and is generally used in high end/luxury projects - https://armourcoat.com/en/ - it is however beautiful and will last for centuries if maintained properly.

There is however an option which is rarely considered in mainstream residential work as little is known about it. I am talking about a porcelain panel product which is 3-5mm thick. An example of a manufacturer is - https://www.porcelanosa.com/gb/wall-tiles/xlight.php - however there are a number of other good ones around. This link is to another manufacturer https://www.levantina.com/en/application/interior-walls/ 

The wonderful thing about these products is they come in sheets of at least 3,000mm x 1,000 and even larger sizes are available dependent upon the manufacturer and style. The finishes imitate natural stone and wood finishes, as well as other options, so well that it is very difficult to tell the difference until you actually touch them and even then there can be doubt.

From a residential point of view they are a great material to use as they can be applied directly to an existing tile finish. What is more they can also be used for flooring, worktops, exterior facades, etc., etc.

Some will say that it is ridiculous to say that a 3.5mm thick porcelain product can be used for flooring, however they would be wrong as we have been using it for many years on commercial offices and retail areas where the traffic is considerable.

Installation is very quick, the materials is easy to cut and mitred corners can be achieve but with the finished edge lightly sanded to protect the corner.

Best of luck with your project!

@Brandler, Dekton is also used for floors and wall panels (it was their original market before kitchen tops), lovely large surfaces, but very very pricey too.

@rinq - I know the Dekton product but there are other options available that are much less expensive

@rinq. I hope it is, it's not particularly cheap! Given tadelakt has been used/lasted in morocco for hundreds of years without issue (as I understand it) do you have info to the contrary? I know that it needs olive soaping etc once a year, if not more frequently depending how much it's used, but once it loses its water resistance it will show on the walls.

The guy doing mine has had tadelakt in his shower for a number of years but it's not too late to change my mind as I'd hate to spend that much and have a major issue particularly in an old house!

As in: Lasted for hundreds of years in a stone house in a hot country without steamy showers? ;) ;) (I do get your point though)

Thank you all for your help and @brandon I’m really interested in those products you mentioned. I’m going to look into those for sure!!

Sorry!! Typed the name wrongly! Embarrassing but I can’t quite figure out how to change it yet!!