How to seal a limestone floor

Limestone Floor Cleaning and Restoration London

Hardwearing, low-maintenance limestone gives a fantastic finish to a floor. You can also have a rich variety of colours, textures and finishes. But it does need to be sealed post-fitting, just as many other natural materials do. And that’s because it’s a sedimentary rock, mainly comprising calcium carbonate. It’s also naturally porous. So applying a sealant prevents staining.

What are the benefits of sealing limestone?

There are a number of these, including protection for your stone, plus easier ongoing maintenance. While most sealing takes place post-installation, you may have to pre-seal some tiles, to protect the surface from marks during installation. This also stops grout from bleeding into the stone. So in the first instance, assess whether a pre-seal would be a good idea, and whether this is recommended.

What are the different types of sealant?

These generally fall into a couple of different categories; either they’re water-based or ‘solvents’ – i.e. based on spirits. Some are coating-style treatments, which bond with the stone’s surface. And while most treatments have a very natural look, others aim to restore or enhance tiles’ colour.

Solvents or water-based?

Both types of sealant are pretty robust and provide good protection from staining.

But water-based treatments are free from VOCs or volatile organic compounds. And you can apply them over residual moisture, so that it’s more feasible to treat the stone all year round. These treatments also typically resist the impact of UV rays.

If you’re sealing a floor that goes through bifold doors, some treatment offers extra protection for the stone that’s outside, providing extra safeguarding against frost, algae and so on.

Cleaning before sealing

Clean the surface of your limestone thoroughly before you do anything else. Any lingering dirt will just sit between the stone and your sealant. So the surface then looks patchier, and subsequent cleaning becomes harder.

Applying limestone sealant

Once your limestone is clean, dry and grime-free, rinse well and leave for 24 hours to dry.

If your surface is rough cut or riven, tumbled or has a strong texture, apply liberally with a foam roller or paint brush. Apply more coats every hour where a surface is more absorbent.

For smoother surfaces, use a sealant applicator pad, lint-free cloth or sponge. And  then leave to dry. Finally, remove any residual sealant still visible an hour later.

How often should I reseal my floor?

This varies according to a number of factors, including how heavy the traffic over the floor is. But, as a general rule of thumb, reseal every three to five years.

Take the water test

Drop a single bead of water on to the surface of your stone. If it makes the stone look darker or sinks in quickly, resealing is necessary. But if it sits where it lands, your sealing is fine.

Get in touch

Royal Stone Care offers limestone cleaning, restoration and repair in London. If sealing your own floor seems too much of a challenge, call in the professionals. Contact us today to learn more and for a quick, informal quote.