How to remove efflorescence on rendered wall?

[liverbird]

Hi All,

This looks like efflorescence but just wanted to check what is it and how to get rid of it and prevent it from happening. This is just on two of the four sides of the wall.

 

[JacobZ]

Hi @liverbird,

A warm welcome to the Bunnings Workshop community, it is fantastic to have you with us. 

Unfortunately, as efflorescence happens when natural salts present in masonry materials is absorbed by moisture passing through and is deposited on the surface when it dries, long as the pillar is exposed to the elements, there isn't a great way to prevent efflorescence from recurring and the best course of action is to clean and manage it when it shows up.

I'd suggest grabbing some Crommelin 4L Efflorescence Remover to clean the efflorescence.

Mix it in a ratio of 1 part cleaner to 1 part water and apply it to a test area. Allow the visible reaction to stop and then flush with water. If the test is successful, you can follow the same process with the rest of the pillar until all of the efflorescence is removed.

Keep the remaining efflorescence remover in case it reappears.

Let me know if you have any further questions. 

Jacob

[liverbird]

Thanks for this. Does this look like any drainage issues leading to water being absorbed ?

Also, if I want to seal some visible gaps between the rendered wall and the tiling, what product should I use ?

[EricL]

Hello @liverbird 

If it was a drainage issue you would see a water trail on your wall, but looking at your picture it appears to be a general occurrence, and I don't see any discernible patterns. Can you please show us a photo of the gaps? Once we see them, we'll be able to recommend a proper sealer. 

If you need further assistance, please let us know.  

Eric

[liverbird]

Apologies, I meant drainage issues in the ground leading to water coming up thru the wall. Another question is - how can I DIY repair this wall ? U would like to repaint it again.

[JacobZ]

Hi @liverbird,

If it is exposed to pooling water, then yes, it could potentially be an issue relating to drainage. If the water pools against the base of the column, then rises up through the bricks, then it could leach salts through the render, which are then deposited as efflorescence on the surface.

For us to offer our best advice, we really need to see more of the situation. 

Can you show us some photos of the base of the wall and where it is in relation to its surroundings?

Is there a roof above it?

What does the back of the wall look like?

Where are the tiles and the gaps that you mentioned above?

We need to identify how moisture is getting into the wall in order to fix it before painting.

When I have further details, I will happily assist further.

Jacob

[liverbird]

 

 

Here are the photos of that wall with the base as well. I have never seen any water pooling, I suspect the hairline cracks on the renders is thru which the water might be entering. Above this is a balcony. 

The efflorescence is only on two sides and not on all 4

 

[EricL]

Hello @liverbird 

Thank you for the extra photos of your rendered post. It appears that water is somehow making it to the rendered surface, it could be coming from the bottom, but I think it is coming from the top but is only appearing a quarter of the way down. It's possible that there is a leak on the roof and is making its ways down the middle of the post. This could be why you can't see any external evidence of a leak. 

Unless the source of the leak is addressed the efflorescence will continue to occur. If you clean it now the surface will retain its finish for a while and then eventually water will push its way through the render and efflorescence will occur again. Sealing the surface will not be an effective solution as hydrostatic pressure will simply push the sealer off the render as it is coming from behind the render. The source of the water coming into the post must be stopped and then you can clean the surface of the post.

I propose engaging the services of a leak detection specialist so that they can pinpoint where the water is coming from. They'll also offer sealing solutions for the leak in your post.

Let me call on our experienced members @Dave-1, @Nailbag and @AlanM52 for their recommendations.

If you need further assistance, please let us know.

Eric

[Dave-1]

Afternoon @liverbird 

Mmmmm going through the thread I am wondering when you first noticed the effervesance? It dosnt look like its traveling from down to up as I would expect it to be more so on the bottom. Coming down from the top makes more sense and because its 1/3rd of the way down and the rear I would be looking for a leak somewhere before trying to clean it off. Have you got some photos of the balcony above and any watermarks on the corner above? 

Water will always find the easiest way downwards, If you follow the effervesance backwards and look for other flowlines/marking it might help in finding the leak.

Dave

[Nailbag]

Hi @liverbird 

Again as with both @EricL and @Dave-1 I would first establishing the cause before the repair. 

The recommendation of checking for water ingress from above would be my first area. A leak detection specialist or plumber who does this type of work are going to be your best trades for this. 

Nailbag.