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What is Efflorescence and Ways To Remove It

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Efflorescence in Block Paving, Brick walls and Stone

What causes it and what can you do about it?

Gleam Team Cleaning Services Blog – 07581 681994 / 0800 999 5363


Efflorescence is a white crystalline salt deposit that appears on brick walls, block paving, Indian Sandstone patios and other natural stone.

The actual word ‘efflorescence’ is derived from a French word meaning ‘flower out’ and for this reason the appearance of efflorescence is sometimes referred to as ‘bloom’.

The salts appear on the surface as a powdery, white substance and may lie within the brick, concrete or stone building material, or from within the cement or mortar used in construction.

When these salts come into contact with water they dissolve, rise to the surface and then evaporate leaving the efflorescence deposit.

Builders can take steps to try and reduce the risk of efflorescence appearing by carefully controlling the use of water during the construction process or by mixing special additives in the cement or mortar. But the unfortunate reality is that nothing can guarantee that efflorescence won’t appear and it can be extremely frustrating for householders who have just spent thousands on a new patio or retaining wall only to find it is soon contaminated by bloom.

Efflorescence is not structurally damaging and poses no risk to walls, patios or block paving but it is unsightly and can ruin the aesthetic appeal of a structure.


So what can be done about it?

Most experts agree that with natural weathering the efflorescence will eventually fade and disappear. However, there is no way of predicting how long this will take and it could easily be 12 months or more before you see any improvement. On the hand it could start fading within weeks and it’s just a case of wait and see.

Of course this isn’t satisfactory for many people who want to take a more proactive approach to removing efflorescence. Something as simple as a daily brushing with a stiff outdoor broom can help speed its removal and within a few weeks should significantly improve appearance.

Chemical cleaning is another option with solutions such as muriatic acid but care should be taken to research the chemicals being used as their suitability for different surfaces may well vary.

Or you could even consider pressure cleaning block paving driveways but although this is one of our main services we do not recommend it. Pressure washing is often cited as a means of getting rid of efflorescence but in our opinion is only likely to make things worse. The reason is simple.

What caused the efflorescence to appear in the first place? Water mixing with the salts in the building material or cement / mortar. So blasting it at high pressure ensuring even more water penetrates the material may temporarily remove the efflorescence…but it could very soon reappear even worse.

Beware of any irresponsible cleaning contractors who suggest this method to you.

Gleam Team are exterior cleaning specialists based in Maidstone and operating throughout Kent and London. Our professional services include driveway and patio cleaning, building and brickwork cleaning, soft washing, roof cleaning and house exteriors, fascias, soffits and cladding cleaning.

Please call us on 07581 681994 0r 0800 999 5363 or email using our Contact Us page for further information.


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