How to remove staining from Black Limestone before sealing.

Visible stains on Black Limetone

Visible stains on Black Limetone

After quarrying, milling and then packing a black limestone it is possible for residues of moisture and sediment to remain on the surface. If left over a period of months these deposits of mineral and sediment absorb into the pores of the stone. This type of staining can be very difficult to remove using conventional cleaning materials. The following is a guide to help restore the                                                                                     appearance of the stone using a strong                                                                                   cleaner and then sealing to restore and                                                                                   enhance the colour.


1. LTP Grout Stain Remover is applied and 2. GSR scrub immediatelythen immediately scrubbed into the surface using a black emulsifying pad. This should be done for 1 – 2 minutes making sure to cover the whole surface of the stone. This cleaner will slightly etch the surface of the stone to release the stains from within.


3. Rinse well with plenty of water2. Do not leave the cleaner to dwell on the surface. Rinse with water immediately after scrubbing. Change the rinsing water every 5 M².
After cleaning leave surfaces to dry for 24 hours.


4. Leave to dry
3. Once dry, surfaces will appear grey rather than black. The stains should no longer be visible. The surface of the stone has been conditioned ready for sealing.


5. Apply Stoneoil4. Apply a small amount of LTP Stone Oil to the surface of the Limestone and spread out evenly. Leave to absorb into the surface of the stone for 1 hour. Any visible excess after this time work should be worked off using a soft absorbent towel.

6. Spread out evenly

5. The sealer should be left to dry for a minimum of 24 hours with light traffic only.
It will take a further 3 days to reach full hardness, so surfaces should be kept as dry as possible during this time.

Finishing the stone with a light coat of LTP Mattstone should be considered if the stone is to be used in kitchen areas.

INITIAL CLEANING:                LTP GROUT STAIN REMOVER                   1ltr & 5ltr

This should be done after fixing and before sealing LTP-GroutStainRemover5L&1L_2011_Weband grouting to remove calcium carbonate and mineral deposits including dust and dirt that has accumulated during the production and fixing process. Apply undiluted solution to the surface of the stone and agitate immediately with an emulsifying pad. Rinse thoroughly with a separate pot of clean fresh water. Wipe away the released calcium dirt and grime with a mop or sponge and water and leave to dry for 24 hrs.



SEALING:                                      LTP STONEOIL                                        1ltr & 5ltr

Before grouting apply a light coat of LTP Stone Oil, LTP-StoneOil5LTin_1L_Grp_Webcheck that all of the sealer has been
fully absorbed within 1 hour, any excess that remains on the surface after 1 hour should be worked in with a soft cloth or buffing machine. Leave for a further 4 hours or overnight before grouting the joints. Once all residual grout has been removed and the surface and joints are thoroughly dry; apply a final light coat of StoneOil covering the joints as well. Buff to remove any excess within 1 hour and then leave for a minimum of 3 days to fully harden before making excessively wet.


When cleaning or sealing vertical surfaces always start at the top and work down.
Provided that the surfaces are correctly sealed and maintained protection should last 3 – 4 years before considering applying a top up coat. Sealing will not prevent wear from abrasion.Used externally sealers will last between 1 & 2 Years before light cleaning and topping up.
After Intensive cleaning to remove any ingrained dirt or other staining and once dry, always test for moisture ingress. If evident cleaned areas should be re-sealed.
When using LTP Grout Stain Remover, gloves should be worn.
For detailed application instructions please see Technical Data Sheets.
This information is offered without guarantee. The material should be used so as to take account of the local conditions and the surfaces to be treated. In case of doubt, the product should be tried out in an inconspicuous area

2 thoughts on “How to remove staining from Black Limestone before sealing.

  1. The product description for LTP Grout Stain Remover on amazon specifically says “do not use on limestone or acid sensitive surfaces” which limestone is. So can I use this product on black limestone or not?

    • Most external black limestone are rough cut with a riven surface so a mild dilution will not effect the surface too much. If your limestone is either honed, smooth or polished then we would NOT recommend Grout Stain Remover but would advise the use of LTP Powerstripper.
      If in any doubt we always recommend a test area first.

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