We live in South Cambs in a 4-year-old red brick house with a parking area behind it. There is a 6ft high red brick wall around our back garden which continues around the perimeter of the parking area. All of the free-standing walls have two strips of significant white blooming 3 or 4 courses up from the bottom, and 3 or 4 courses down from the top. The east-facing free-standing wall has a white patch 8 courses high. The house itself has less obvious, but still present, white blooming 2-3 courses above the DPC on the shaded side. We are on the edge of the housing development so it's quite windy most of the time.
Jetwashing the white bloom will make it disappear for a week. Scrubbing it with alloy wheel cleaner removes it for 6 months. Is there a permanent remedy? It's just unsightly at the moment, but I'm concerned it may lead to damage in the longer term.
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Isnt this the damp leaching the natural salts out of the bricks?
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>> Isnt this the damp leaching the natural salts out of the bricks?
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That was my understanding, and so jetwashing is likely to just push a proportion, if not all, back into the brickwork so no wonder it comes back quickly. A stiff dry brush would probably be more effective long term, if it bothers you. I imagine over time it’ll improve
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This is a natural occurrence of the salts leeching out from the bricks. The recommended treatment is to brush it off with a stiff brush when it is dry. It may take several years to leech out completely so this will need to be repeated.
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Thanks, I'll treat it to a brushing every so often then, and stay away from it with the chemicals. It's intriguing that the cold walls are more prone to it, but I suppose that's simply because they get wetter and stay that way for longer. The whole estate has the same blooming, to a greater or lesser extent.
The internet has a million and one ideas, but I thought I might find some sense here.
Last edited by: Dave_ on Tue 9 Mar 21 at 21:12
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If this is too long, just read the last bit about hydroflouric acid.
If you've read up on efflorescence you'll know it's something that happens. At some point those bricks have got very wet, and the salts come out in solution and dry out or crystallize on the surface.
I'm building a house and I'm slightly concerned as another newly built house locally, clad with the same facing brick and finished about 2 years ago, has started showing some efflorescence. I chose the bricks (Freshfield Lane FQM if anybody is interested) primarily for their appearance but I did note that their water absorbency was at the lower end of the scale which I hoped might preclude it. The bricks have just been delivered and they aren't wrapped, and I suspect they probably got very wet indeed in sustained heavy rain a few weeks ago when they were almost certainly outside in storage. They can also take up water from mortar. Time will tell
I did learn about it nearly 50 years ago in materials science so I knew something about it. I think this from the Ibstock brick website covers it fairly well.
www.ibstockbrick.co.uk/wp-content/uploads/2015/08/Ibstock-TIS-B1-EFFLORESCENCE.pdf#:~:text=What%20is%20efflorescence.,during%20construction%20or%20from%20rain.
Unless the bricks keep getting wet it does tend to diminish over time, so on the house it's worth ensuring gutters don't leak or spill etc. and the dpc hasn't failed allowing the wall to get damp. You'd imagine that there would be a way of dissolving it and washing it away and you can but as you have discovered if you chuck more water at it it can bring out more salts. Repeated mechanical removal (brushing) although laborious seems to be the only fix but it does come back at least initially.
I would have thought brick sealant might be worth trying but apparently not advised.
It's unlikely to cause damage if it's just efflorescence provided the walls are not getting perpetually soaked when the bricks can become saturated and water penetration can eventually cause spalling.
I don't think there is a sliver bullet for it. I'd be very wary of treating it with anything like wheel cleaner - there are two sorts, the surfactants and the acid. The surfactants work by reducing surface tension and making water wetter. Bad idea I should think as it will then penetrate better and potentially prolong the problem. For the same reason, don't use detergent if you are sponging or jet washing.
The wheel cleaner probably works for longer because the acid neutralises the alkaline salt solution but I have no idea what repeated applications of phosphoric acid does to masonry. Some trade wheel cleaners use hydroflouric acid which is very toxic stuff, potentially dangerous to you and I wouldn't want to be using it for hours at a time or in any way that might get it on my skin (do your own research, seriously).
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>>Some trade wheel cleaners use hydroflouric acid which is very toxic stuff, potentially dangerous
Read the first pages of many Haynes manuals about recovering parts from burnt out cars.
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Efflorescence on brick walls - Zero
