re sealing shower tray

[xtine]

Hi I'm new - hope someone can give me some advice.
FACTS:
I had a corner shower unit professionally fitted four years ago and no problems with leaks until a few months ago.
Over the pas few months water has been dripping on my kitchen table.
I tested the plughole by running shower head into it for 10 minutes - no leak therefor consider it is a sealant problem.
Some of the sealant has gone black (mould).
I suspect the problem is in one corner.
I've tried lots of make-do, even badly re-sealing on top now I have got to do it 'properly'.
I spent a good hour last night trying to remove old sealant it is very hard work - it is so resistant.
I am also using a brush applied sealant remover gel from Wilkinsons. it takes 15mins to 'work' says it removes all types of sealant - how do I know the original one was silicone?
There is another silicone only sealant remover by Uni bond - twice as expensive I haven't tried - that takes three hours -

I have bought the 'Uni bond bathroom and shower mould resistant' gun applied sealant. But I noticed afterwards there was one in Homebase that said it was a new type - non-silicone can be applied on wet areas...would that have been better? (How much money have I to spend on this DIY?)
So I will work away on the stripping. Could the mould be a clue as to why it was leaking? Any advice please.
I can't bear life without my shower. The plumber who installed it has disappeared.

 

[magzy]

try a stanley blade rub it along on sharp side but make sure the hole edge of the blade is contacting surface on the tiled side should be a piece of cake ,just need to be careful on tray. 2nd make sure there is no movement in tray ,you may need to adjust feet. make sure it is completely dry before attempting to re-seal

 

[hampshireman]

I fitted a walk in tray, as big as a bath, a 4 years back but basically I was given the wrong fitting instructions when I unpacked it - however that's another story.

It is plastic and already in 4 yrs I have removed the original sealant and replaced it using one of those sealant eater products.

I think over the years it still leaks but a very little judging by the ceiling below. It also moves and creaks when showering. I am going to have to reseal again, but first of all will remove part of the ceiling and investigate the (if any) damage then redecorate the room.

What did you use finally?

 

[wingcoax]

Have done several re-seals in last two years and find stanley blade and unibond work as well as anything, just make sure that everything is clean and dry.

 

[hampshireman]

Ah OK thanks, I did use a Stanley plus the sealer eater last time. Will take a look at Unibond

 

[bernardgreen]

A friend with a "loose" shower tray that kept breaking the seals did a quick bodge temporary repair by injecting expanding foam under the shower tray. Heavy weights in the tray to prevent the foam lifting the tray. The tray was then no longer loose. This temporary repair has lasted for 8 years and no apparent leaks and the shower is used 3 or 4 times a day.

 

[neds]

As suggested you may have underlying problems such as the Shower tray moving. The floorboards may be flexing. I always make sure when refitting things like baths and toilets that I rip out the floor boards and strengthen the joists below it so when the floorboards are laid back on there is more strengh beneath it.

 

[hampshireman]

The tray was bedded on a silicone layer on a piece of 20mm marine ply with lays on the floor boards. I had the wrong fitting instructions with the package and that caused me all sorts of problems, finally sorted free of charge by the supplier, but this could be related, although I have no comeback on them now.