Caring for a granite headstone

Granite is the most durable stone a family can choose, which is exactly why it is easy to care for badly: it looks as though it can take anything. It cannot. Most damage to memorials is done by well-meaning cleaning. The good news is that doing it properly takes less effort, not more.

Before you clean anything

• Ask the cemetery. Many cemeteries have rules about cleaning and about what may be applied to stone, and some prefer to do the work themselves.
• Look at the stone. If it leans, rocks, has cracks or flaking, or if the base has shifted, do not clean it. Report it to the cemetery or the fabricator instead.
• Check the weather. Never clean when there is any chance of frost within a day; water trapped in the cuts and freezing will do more harm than a decade of grime.
• Accept some ageing. A memorial is outdoors for generations. The aim is to keep it legible and sound, not showroom-new.

What you need

Four things, and nothing else:

1. Plenty of clean water, ideally distilled or at least soft; tap water with high iron or mineral content can leave stains.
2. A soft natural-bristle or nylon brush. Toothbrushes are good for lettering.
3. Plastic or wooden scrapers for lichen and moss.
4. A biological cleaner formulated for stone, such as D/2 Biological Solution, which conservators and cemetery authorities widely recommend. It kills the algae and lichen that discolour stone and keeps working for months after rinsing.

The method

1. Wet the stone thoroughly and keep it wet throughout. Dry stone draws dirt and cleaner into its pores.
2. Lift loose growth with the plastic scraper, gently. Anything that does not come away easily is left for the cleaner.
3. Apply the cleaner as a light spray, from a couple of angles so it reaches into the lettering. Follow the label for how long to leave it, usually ten to fifteen minutes, and do not let it dry.
4. Brush gently, in small circles, working from the bottom up to avoid streaks.
5. Rinse generously, including the grass around the base.
6. Walk away. Biological cleaners keep acting; the stone will look noticeably better over the following weeks and months, which is why a second scrub the same day is unnecessary.

Once or twice a year is plenty. A quick rinse and a brush of the lettering on an ordinary visit does most of the work.

What never to use

• Bleach, ammonia or household cleaners. They leave salts in the stone that reappear as white bloom and slowly break down the surface.
• Acids, including vinegar. Granite tolerates them better than marble, but polished faces dull and any marble component is etched immediately.
• Pressure washers. They drive water into the stone, strip polish and lift lettering fill. Conservation bodies are unanimous on this one.
• Wire brushes, steel wool or metal scrapers. They scratch, and the steel particles they leave behind rust.
• Shaving cream, flour or chalk to read a worn inscription. All of them leave residues that feed growth. Use a mirror to rake sunlight across the face instead.

Marble is different

If the memorial, or part of it, is marble, be gentler still. Marble is soft and dissolves in mild acid, so water, a soft brush and a stone-safe biological cleaner are the whole kit, and scraping should be avoided. Our comparison of granite and marble explains why the two stones age so differently.

When to call someone

• The stone or base has moved, tilted or sunk.
• Lettering fill or gold leaf is lifting.
• There are cracks, chips or flaking.
• A stain has not responded to two gentle cleanings.
• The stone is old, historic or fragile.

The fabricator who set the stone, or the cemetery, is the first call. For re-levelling and repair, use a monument company rather than a general contractor; the weights and the foundations are specialised work.

A granite memorial cleaned this way, once or twice a year, will carry its inscription clearly for the grandchildren of the people who chose it. That is the whole point of the stone.