Cleaning Headstones 

How To Clean Marble Granite & Concrete Headstones with Bio-Shield

Headstones are frequently discoloured by algae, and lichens and the often remote locations can make cleaning difficult.
A single application of Bio-Shield to the headstone will kill and remove the algae and lichens - No wash down or scrubbing is required
If the Headstones are treated with Bio-Shield every 12 to 24 months, they will stay clean and protected from regrowth.

  • Easy spray-on application - 1 coat is enough.
  • No Pressure Cleaning or Scrubbing
  • Bio-Shield® protects from algae and lichen regrowth

Returned Services Association - National War Graves Restoration Project

Bio-Shield is proud to be supporting the  National War Graves Restoration Project and the volunteer Remembrance Army.
The goal of the Remembrance Army is that every service grave in New Zealand is restored to the same as their comrades overseas, maintained to the same standards or better as the Commonwealth War Graves Commission.  Since the project started in 2019, the Volunteer Army have used Bio-Shield to clean and restore over 150,000 of the 200,000 war graves and monuments throughout New Zealand.

Join Up

Grave Restoration Guide
Download: Expert tips on grave restoration

Why choose Bio-Shield® for your DIY Headstone Cleaning

Bio-Shield® has been developed through 39 years of use in a demanding commercial environment and it works extremely well.
Bio-Shield® is a high quality product, and contains no bleach, salts, acids or phosphates, so it will not damage the gravestone.
The high concentration of active ingredients in Bio-Shield® when compared to other outdoor cleaners means it will cost less per diluted litre and cover more area at a lower cost.

I have used your product for removing lichen and moss from headstones and it works brilliantly. Recommend all monumental masons use your product.
Ian - Maiden Stone Ltd. March 2018

Bio-Shield Mixing Ratios - for Pressure Sprayer

Clean WaterBio-Shield ConcentrateTotal of Diluted Bio-Shield
1 Litre50 ml1.05 Litres
10 Litres500 ml10.5 Litres
15 Litres750 ml15.75 Litres
20 Litres1 Litre21 Litres


Application is best done on an overcast day at any time of the year, or early morning and late afternoon in summer if a warm sunny day is forecast. This slows evaporation and speeds the treatment process.

Fill your sprayer with the premixed Bio-Shield® solution and pump it up to pressure.
Begin application to the top surface, working down in slow, even strokes ensuring saturation.
Aim for the surface to stay wet for 5 to 10 minutes after application.

On concrete plinths and lighter colored stone like marble there will be a distinctive orange brown color change.  This is normal and will  fade over 24 to 48 hours.


The treated surface may clean up over the next few months providing it is exposed to rainfall; however it would not be unusual for a very dirty surface to take up to 12 months to fully clean up.
The more rain the surface receives, the faster it will clean up.
It is best to reapply Bio-Shield® at the first signs of re-growth. Typically this will be every 2 to 3 years.

Once the surface is clean Bio-Shield®  will give optimal results with regular applications. This will kill spores and prevent the build up of moss, algae and lichen growths.