White marks on brickwork - how do I get rid of them?

We have a raised area of the garden with a dwarf brick wall around it and steps to the upper level. Ever since the wall was built, 2 years ago, the brickwork has white stains/patches all over it. How do I get rid of it?

 

Hi, more than likely it will be cement stain if so plenty of information here, make sure you wear gloves and eye protection, I find a high powered jet wash helps after the acid is applied.
https://www.google.co.uk/?gws_rd=ssl#q=cement+on+brick+removal

 

Is this the problem?
https://knoji.com/how-to-remove-efflorescence-from-brick

 

Thanks Martin. We did give it a blast with the jet wash but I think it actually looks worse since we did it.

 

Yes Pete, it looks like it.

 

You need to blast it after acid application, jet wash no acid will do nothing its cement stain .

 

Where would I get the acid from - B&Q, Wickes etc?

 

Get this Kaz, follow safety instructions to the book
http://www.wickes.co.uk/Wickes-Bric...content=sP3EZWTpW|pcid|73770331732|pkw||pmt||

 

Another thing if you have plants below the wall it will kill them.

 

I could be wrong, but could it be salt being drawn out from the sand by the dry weather

@Zigs

 

Jet washing will only cause a wetting/drying cycle that will mobilise more salts from within the masonry.

Best wait till it's dry and then use a non ferrous wire brush in a circular motion.

Or, as Woo says, paint it

 

90% of it is cement, regardless the cleaner ive linked to will sort both out, @wiseowl has the best idea if plants are around .

 

Could the fact that there is soil behind the wall with no liner between, have any bearing on it?

 

Yep, water migrating thru the wall will drag the salts with it.

If you want to go to extremes, you could saturate the wall and then put a poultice on it, let it dry and the salts will crystalise out on the surface of the poultice, which you then remove.