Is this efflorescence?

[smot]

Hi Team, my outdoor tiles as well as one shower has this white stuff coming through the outdoor tiles.  These tiles were laid around 3-4 years ago, and are on an outdoor verandah, uncovered to the elements.

Someone had told me it was the waterproofing leaking through, but in reading this forum I now think this is probably efflorescence from the grout.  Would you agree? 

 

 

[JacobZ]

Hi @smot,

A warm welcome to the Bunnings Workshop community and thank you for your question.

Does it feel powdery? Is there any smell to it? 

It certainly looks like efflorescence to me. The only other thing I could think that it might be is mould. With either of these possibilities, I'd suggest giving it a good scrub with some Davco 1L Tile And Grout Cleaner and a scrubbing brush. Mix it to a ratio of 10 parts water to 1 part tile and grout cleaner. Apply the solution to the affected areas and scrub until it has been removed. Make sure you wear a mask and rubber gloves to protect yourself whilst cleaning.

Once it has been removed, allow the area to fully dry. You can then apply Dunlop 250ml Grout Sealer to the grout lines to add water resistance and help prevent any reoccurrence of the issue.

Let me know what you think and if you have further questions, please don't hesitate to ask.

Jacob