Silicone over grout...

[Rich]

Evening all. I have just replaced the silicone around my mothers bath as the ols silicone had split and come away. I thought while I was doing it I would take some snaps so that I could put up a post on the dangers of using silicone over grout.

Using a silicone joint in tiling is not just to make a nice finish. It is used to keep the joint water proof and it is also used as a movement joint. At any junction where tiles meet another object like a bath, basin or another tiled wall/floor the joint between the two should be left totally clear of grout. I find that the best way to do this is to grout in all the joints running into the expansion joint and let the grout set off, then I run a knife or a paint scraper along the movement joint to remove all the grout. I then let the grout dry completely. When I come back to silicone, I make sure all the joints to be siliconed are clear of any grout/adhesive/dust but sweeping, scraping and hoovering the joint out. After this I give all the joints a wipe over with meths on a rag to remove any grease and grime. Then I am ready to apply the silicone. The silicone is there because it is much more flexible than grout, grout will just crack and will let water through. If you grout these joints and then just silicone over the top, the grout will crack and come away from the joint taking the silicone with it, this is what has happened in my mothers bathroom below.



You will have to ignore if you can the god awful tiling, it was done by my step dad many years ago, he is so proud of it bless him it has never been changed. If this room had been tiled by a pro the cuts along the top of the bath would (should) be even all the way along the length of the bath (makes it easier when it comes to silicone).



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Notice how the grout has come away from the joint behind the silicone and taken the silicone with it.




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A stanley knife is used to cut out all grout/adhesive/grit from the movement joint then the joint is hoovered out to remove all dust.



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The joint is then cleaned, rubbing a clean rag with meths along the joints will get rid of any grease and will totally evaporate and leave no residue.
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To be safe I give the joints a quick brush out with a clean brush to make sure no dust has settled in the joint after I have hoovered it out.

[whitebeam]

Amazing the difference a bit of silicone can make

[Gazrus]

Nice informative post here Dylante, I'm sure it will benefit a lot of the budding tilers on here.

[aph257]

that sums it up nicely Rich.

[Sir Ramic]

When you doing the regrout ??

[Rich]

When you doing the regrout ??

Its rough isnt it. Not aloud to touch it im afraid.

[Derry]

great info and pics dylante and it looks so much better once freshly siliconed!

[Rich]

Thank you guys. I seem to get more and more work from people that have had wet rooms done and are letting water through. It is usally clear what has caused it before I even go and look at it. Something so simple but can totally ruin a job.

Oh well, keeps me busy I suppose. I hope some1 gets some helpful info from this thread, might just save them a fortune.

[KylieZona]

I was looking for exactly this information, Rich. Thanks for the great post!

[Rich]

I was looking for exactly this information, Rich. Thanks for the great post!

Tilersforums saves the day again