Is it essential to use sealant over grout on corners in tiled wet room?

[SueP]

I have a fully tiled wet room, the floor is concrete and the transparent sealant along the corners / floor edges gets mould behind it very quickly. I have had to remove it twice so far and replace it within a few years. I have removed the sealant and re grouted the edges.
I can't find out why sealant is necessary - surely the grout is sufficent?

 

[WetSaw]

Grout isn't AS flexible and is likely to crack on transition joints where there is a possibility of movement.

 

[Flintstone]

There should be no grout there at all, just Silicon !

 

[Stevev]

As I undertand it, You use one or the other. If you can see mould behind the sealant then moisture is getting behind. The reason why sealant is used is that wall can move slightly and grout would crack, so a sealant is better because it stretches with the wall. The gap in the corners need to be slightly larger than the grout gap to allow the seaant to squeeze into the gap and form a plug behind the gap. Theres no point sealing over grout as theres no gap to plug. A bathroom will look better with grout in the corners but sooner or later it will crack.

 

[Natwasere]

Mould behind... water getting in, reckon it's not siliconed properly. Remove, clean and redo.... What are you using to tool? Fingers are not good tools for Silicon imo, every time I see it done with fingers it usually fails over time. Does it have to be clear? Not a fan of clear as there is a multitude of colours available these days

 

[NZ_Tiler]

When you removed the mouldy Silicon did you also clean it with a mould remover?

If mould was still present on a micro level it comes right back.

As above, no grout in corners, should be siliconed to allow for movement.

 

[Tilerdurden]

When you removed the mouldy Silicon did you also clean it with a mould remover?

If mould was still present on a micro level it comes right back.

As above, no grout in corners, should be siliconed to allow for movement.

I concur. The Silicon acts with flexibility to ensure any movement doesn't crack the grout at abutments and wall junctions.

 

[SueP]

Thanks everyone for the feedback!