This journal entry teaches users how to remove limescale from roof tiles. Limescale or Efflorescence are used interchangeably throughout this blog; it is used to convey the salt deposits. It is associated with moisture emigrating through the substrate leaving behind the salt deposits as seen in the pictures.  

As aforementioned, as the water evaporates and it leaves the behind the unsightly salt deposits referred to as limescale. First of all, it is important to find out the material of the surface with the limescale. Roof tiles can be made from a range of materials. In this case the tiles are made of clay, as seen in the pictures. There are a number of solutions to try to remove the efflorescence. Although, limescale is notoriously hard to remove.  

Removing Limescale from Roof Tiles 

Surrey Jet Washing suggest you use the least intrusive chemical products in the first instance to remove the efflorescence, before moving onto stronger solutions if needed.  

The first product we suggest you use is a white vinegar and baking soda solution. Vinegar is acidic, therefore, can help breakdown the mineral deposits within the hard water stains. Whilst the baking soda helps to remove the salt stains. Therefore, we recommend the use of 2 cups of bicarbonate of soda (baking soda) to 1 part vinegar (or lemon juice) (source – Mix together which will provide a paste like substance, which can be applied generously to the affected tiles. Jet washers or exterior cleaners often add water to the mix to provide a solution which can be applied with a pump. Although, we avoid adding water when cleaning limescale as it may compound to the problem; as the root of the issue is moisture in the first place. Leave the paste to penetrate and break down the efflorescence for 15-30 minutes, then scrape off and remove the paste and gently wash away the area to ensure the limescale has been removed. If there are still salt deposits, repeat the process from the start.

 Close up of limescale on roof tiles

If the vinegar and bicarbonate of soda does not remove the limescale on roof tiles there are stronger acid products to try. The acidic products are usually hydrofluoric, phosphoric or hydrochloric acid based. Please read, and follow the guidelines shown on these products, as they can be very dangerous. Therefore, it’s very important that PPE is used.  

Once the limescale is removed, it may be worth sealing the tiled roof. This creates a thin and invisible layer of protection for the tiles. This stops moisture entering and leaving the hard surface. Sealing has shown to be very effective at restricting salt deposits.  


Calcium salt deposits, or limescale appear on roof tiles due to moisture being released through the substrate. More, it is notoriously difficult to remove the salt deposits and may be worth looking for the root cause of moisture or it may reappear.  

Using a bicarbonate of soda and vinegar paste on the affected area can be very effective at removing the limescale. Although, if very stubborn you can use a professional acid-based product. Once the limescale has been removed seal the hard surface to limit the reappearance of efflorescence. For further advice contact Surrey Jet Washing.