What is Efflorescence?

There are a number of methods for removing efflorescence effectively from limestone.

Importantly, as limestone is acid sensitive, it is important to use solutions that will not damage your stone and always test any product in an inconspicuous area first.

Efflorescence, in its very early stages can be removed using certain non-acidic cleaning solutions and an abrasive nylon pad, however once it becomes insoluble can be very difficult to remove. In its more advanced stages efflorescence will require specialist equipment and removal solutions.

Once the removal process is finished and the surface is completely dry, you should reseal your limestone using a long lasting penetrating sealer which greatly reduces water uptake.

Efflorescence can be removed, however it is an indication of another issue which will need to be dealt with to prevent the problem from simply recurring.

Water entry to the tiling system can be minimised by binding, waterproofing and sealing, among other options. Without water, the efflorescence cannot form.

The two key principles for minimising efflorescence are to minimise the entry of water into the tiling system, and to direct water that penetrates the tiling system to a designed outlet.

Sealing using a penetrating sealer will prevent water from being absorbed into limestone and also allow the stone to release any built up vapour. Unsealed limestone that has absorbed moisture can also result in efflorescence being deposited on the surface as the moisture evaporates.

Topical coatings which block the pores should be avoided. They can trap water inside the material and make the surface dangerously slippery when wet.

Efflorescence is a whitish crystalline deposit that manifests on the surface of limestone. The formation of these unsightly salt deposits are for the most part, water-soluble salts that come from many possible sources.
For efflorescence to occur there must be water present to dissolve and transport the salts. For water to carry or move salts to the surface there must also be channels through which to move and migrate. The more dense the limestone, the more difficult it will be for water to transport salts to the surface. Conversely, the more porous the material, the greater the ease with which salts are transported and deposited.
Salt-bearing water, on reaching the limestone surface of a structure, evaporates and deposits the salts. When humidity is low, the water may evaporate before reaching the surface of the structure, leaving the salt deposit beneath the surface, and unseen. When the humidity is high, water evaporation is slower allowing more opportunity for visible growth.
There must two conditions present to create efflorescence

• A source of water-soluble salts.
• Water moving through the material to carry the salts to the surface. The water evaporates and leaves the white powder (efflorescence) behind.

Some surfacing products are more prone to have efflorescence because:

• They might be more permeable and promote water travel.
• They might tend to have higher water-soluble salts in some batches.

The best time to deal with efflorescence and remove its salt residue is before it hardens using a non-acidic efflorescence cleaner.
If you are not sure how your limestone reacts to any type of cleaners the best approach is to test a small area first. If you are happy with the results you then can apply the product to the rest of the area.
In most circumstances the salts will have hardened and a cleaning solution will be required to break down the salt deposit and remove it from the surface. However as limestone is very acid sensitive and can easily etch / discolour, non-acidic solutions combined with specialist equipment will most likely be required.
Get in contact with a professional stone floor care company with the equipment and knowledge to ensure you're valuable surfaces look just how you want them to.

Get in contact with a professional stone floor maintenance company with the equipment and knowledge to ensure you're limestone surfaces look just how you want them.

Tile Cleaners Australia and StoneMaster are members of the network of independent Accredited Applicators who have been fully trained in the proper application of limestone care products, offering a full service by thoroughly cleaning the limestone area to be treated, product application and providing after sales care.

• Tile Cleaners Australia is Australia's leading tile care provider of all tile & grout cleaning, tile sealing, tile stripping & sealing, tile regrouting, grout colour sealing, and minor tile repairs.
• StoneMaster provide a diagnostic approach to each unique situation, including a full analysis, selection of the best-required method of restoration and follow up maintenance procedures always ensuring outstanding results.

Ensuring your limestone is thoroughly cleaned before sealing is important as you may seal in old stains or dust and debris embedded in the stone, resulting in the sealer needing to be stripped and resealed.

Applying a sealer that is not suitable or of sufficient quality will result in limestone surfaces you aren't completely satisfied with.