Welcome to the UK Window Cleaning Forums

Starting or own a window cleaning business? We're a network of window cleaners sharing advice, tips & experience. Rounds for sale & more. Join us today!

Efflorescence and brick acid

maddydog

Member
Messages
68
Location
north staffs
I've recently cleaned some block paving for a commercial client and some patches of efflorescence have appeared.

They're fine about it and understand the reasons as to why but they want it removed for an upcoming event.

Just wondered if anyone had experience of using brick acid? Concentration? Leave on heavily diluted or rinse off? Etc. 

Cheers

 
If efflorescence wasn't a problem before it's probably the pressure washing that caused it and only likely to be temporary.

But for immediate results I use Resiblock ER. Just apply and rinse - repeat if necessary.

Hydrochloric acid removes efflorescence.

 
Typical, went there yesterday and it's only a tiny amount of efflorescence. The majority of the staining was crushed limestone chippings left by the landscapers after they tidied the beds up. To show willing I washed it down anyway and tidied up all the other areas the landscapers have been.

 
Just a quick note efflorescence, is not in the block paving, nor is it in bricks or concrete blocks, it come from the cement, more often Portland cement. So when you see the side of walls with white powder like effect, the white powder effect is from the cement not the bricks. 

 
You're quite right about the cement and efflorescence is salts within the cement rising to the surface when mixed with water. But it can appear in any concrete blocks/slabs etc because of the cement used in construction of the blocks/slabs.

That's how it appears in concrete block paving which has no mortar/cement in the joints.

 
Last edited by a moderator:
But for immediate results I use Resiblock ER. Just apply and rinse - repeat if necessary.

Hydrochloric acid removes efflorescence
K you obviously know your efflorescence from your effervesce ? would appreciate your (or any other expert's) wisdom... 

I've been asked to take a look at a really bad case...possible leaking gutter/overflow pipes which have now be removed leaving a 6m by 0.5m cascade down a brickface - large site with several instances in various places (all where water sources overflow/downpipes were but are no longer present) condition ranges from bad to the worst I've ever seen...the very worse area has a 'calcium' like white texture covering the area which is raised 1-2mm to touch...along with the other areas with your more usual powdery cloudy staining.

Question : what's, the best way to remove ? Resiblock ER or Hydrochoric ?

Best approach? e.g test in an inconspicuous area first, using one the treatments, assess removal rate, repeat etc or opt for the more 'aggressive' of the two if not shifting fast enough per application? 

Any thoughts/input appreciated?

 
Last edited by a moderator:
K you obviously know your efflorescence from your effervesce ? would appreciate your (or any other expert's) wisdom... 

I've been asked to take a look at a really bad case...possible leaking gutter/overflow pipes which have now be removed leaving a 6m by 0.5m cascade down a brickface - large site with several instances in various places (all where water sources overflow/downpipes were but are no longer present) condition ranges from bad to the worst I've ever seen...the very worse area has a 'calcium' like white texture covering the area which is raised 1-2mm to touch...along with the other areas with your more usual powdery cloudy staining.

Question : what's, the best way to remove ? Resiblock ER or Hydrochoric ?

Best approach? e.g test in an inconspicuous area first, using one the treatments, assess removal rate, repeat etc or opt for the more 'aggressive' of the two if not shifting fast enough per application? 

Any thoughts/input appreciated?
Hello mate, no not really but I have got some experience dealing with it. Are you sure it's efflorescence and not limescale / hard water deposits left by water from the pipes? Either way I'd go with the acid - Sika Brick Cleaner from Wickes or Bostik from Toolstation - you want the Brick & Patio Cleaner, not the mortar one they also sell which is weaker.

This is the link to the right one

I'd start by giving the stains a hard brush with a stiff broom and see if any comes away. If it is efflorescence you want to try and draw the salts to the surface. I'd then very slightly dampen the stain before applying a fairly weak brick cleaner solution mixed with water e.g. 1 part cleaner to 3-4 parts water. Apply it with a sponge (wearing gloves, glasses etc because it's nasty stuff). Scrub again with broom and leave for 20 minutes. Then very light rinse with sponge and clean water and repeat the process, perhaps with a stronger mix - 50/50. Regularly scrub it with the broom to work it into the surface and draw out the bloom.

If you're still left with any salts wipe over them lightly with soapy water/ sponge. If it is hard water deposits you might want to try a wire brush if you can do it without damaging the bricks and wet bricks first. But don't use too much water throughout the process. With brick acid it's always best to pre-wet any areas you want to treat - and anywhere run-off might go. And a final rinse when you finish. And yes, try inconspicuous area first

 
Nice one K - i think the active agent is hydrochloric acid in that link - just got some today ? 

I *think* it's efflorescence as the water source was leaking gutters -hence rainwater - which we know is pretty soft - hence more likely to be efflorescence (?) I'm going to use several different treatments on each area to try to correctly diagnose what I'm dealing with at each location, as you rightly say some locations it is defo from boiler/cistern overflows so there it's more likely to be limescale...

They just agreed to my trial clean and stumped up to $ to cover it...will let you know how it goes....

 
Nice one K - i think the active agent is hydrochloric acid in that link - just got some today ? 

I *think* it's efflorescence as the water source was leaking gutters -hence rainwater - which we know is pretty soft - hence more likely to be efflorescence (?) I'm going to use several different treatments on each area to try to correctly diagnose what I'm dealing with at each location, as you rightly say some locations it is defo from boiler/cistern overflows so there it's more likely to be limescale...

They just agreed to my trial clean and stumped up to $ to cover it...will let you know how it goes....
Yeah you're right, it is the acid that does the job and the Cementone Brick Cleaner in the link is an all purpose brick cleaner for limescale and other staining, and I think a bit stronger than the other Bostik product Toolstation sell. Sika and Cementone will both deal with efflorescence.

If it is the rainwater look for any obvious areas it is penetrating the wall. The water must be getting in somewhere to activate the soluble salts and cause efflorescence, so could be cracks / holes in the brick or mortar amongst other things. You should be able to improve the appearance but the efflorescence is likely to return if the source of the water isn't dealt with....and don't forget the stiff broom because this a good way to draw the salts out on bricks and patio slabs.

 
Back
Top
AdBlock Detected

We get it. Advertisements are annoying!

Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website.

Our website also relies on advertising to keep the doors open and the lights on!

For the best site experience, please disable your AdBlocker.

I've Disabled AdBlock