HomeHelpline: +44 (0)1823 666213


Published 28 May 2024



Black stone creates a stunning aesthetic – and treatments like LTP Blackstone protect the surface and restore colour to faded surfaces. So job done? Not quite. It’s very important to ensure that surfaces are properly cleaned and prepared before any restoration is carried out.

LTP Blackstone - application image_2

When a restorative treatment like LTP Blackstone Sealer & Restorer is applied to black stone, it mixes with any loose particles of limestone. These particles are caused by etching which occurs when the stone comes into contact with acidic rain. The etching creates a sediment which is carried into newly exposed capillaries and the sealer, in turn, draws the sediment out of open pores. When this residue mixes with the sealer, it creates a smeared and patchy appearance.

To avoid this happening, the surface should be thoroughly cleaned to remove the sediment and condition the stone. If you rub your hand across the surface before cleaning, you’ll see a dusty residue; that’s the limestone sediment.  Cleaning the surface opens the pores and prepares the stone for application of the sealer.  Here is a link, which includes full preparation directions for new and older surfaces.

LTP Grimex 5ltrLTP Blackspot & Algae Remover 5ltrLTP_2018_5 lit Blackstone Sealer

LTP Grimex is ideal for preparing new surfaces before application of Blackstone. For older surfaces, we recommend LTP Black Spot & Algae Remover to remove blackspot, algae, mildew and stains.

Don’t be tempted to over-apply LTP Blackstone in order to achieve a darker finish or speed the process up.  Less is more. It’s far better to apply several thin layers than one thick layer.  If you apply too much product in one go it won’t be absorbed properly and the finish will be patchy.  Here is a link to application directions.

Any residue treatment should be removed with LTP Power Stripper, using a diluted 1:10 solution as explained in the instructions.  This is an important part of the process because the treatment only works in the pores of the stone, where the formulation cross links to make the sealer colourfast.  This final clean won’t return the stone to its original colour, it will just remove any excess treatment that hasn’t been absorbed and is effectively just sitting on the surface. 


For more information about black stone and the application of LTP Blackstone Sealer & Restorer, see our blog Black Stone issues – Series One: How to restore colour to black stone.  The Blackstone product page also includes additional information, including a video aid and coverage calculator.

To watch video demos, visit LTP TV.

For more information and expert advice on surface protection and maintenance, please contact LTP on tel. 01823 666213 or email [email protected]

ends  –

For media information and photography, please contact Angela Fitzhugh PR Ltd on tel. (01579) 673026 or email [email protected]