Stone, brick, concrete and terracotta are porous. Rain, spills and salts travel into them through millions of tiny capillaries, and that is where stains, damp patches, efflorescence and moss begin. A penetrating sealer stops the water at the pores without putting a film on the surface. This guide explains how that works, which surfaces need it, and how to apply it so it lasts.

What a penetrating stone sealer does

Most sealers people know are topical: varnishes, acrylics and wet-look coatings that sit on the surface as a film. They change how the stone looks, they can trap moisture underneath, and they wear, peel or yellow in sun and foot traffic.

A penetrating sealer works inside the stone instead. It soaks into the pores and bonds to the mineral surfaces within them, lining each pore so that water beads and runs off rather than being drawn in. Because the pores stay open, water vapour from inside the wall can still escape. The stone keeps breathing, keeps its natural colour and texture, and has nothing on its surface to scuff or peel.

Nanoman Stone + Brick is a PFAS-free nano sealer of this kind. It is supplied as a concentrate that you dilute with deionised water on site.

Which surfaces benefit, and what to watch for on each

Natural stone: sandstone, limestone, travertine, granite, honed marble

Soft, open stones like sandstone and limestone absorb the most and stain the fastest, so they gain the most from sealing. Dense stones such as granite and honed marble absorb less, so apply less and wipe off any surplus within 10–15 minutes so nothing dries on the face. Polished marble is usually too dense to take a penetrating sealer; test a small area first.

Brick and terracotta

Exposed brick and terracotta walls soak up monsoon rain, then release salts as they dry: the white bloom called efflorescence. A brick sealer that stays breathable reduces how much water gets in, so there is less to carry salts to the surface. Clean existing efflorescence off and let the wall dry fully before sealing, or you seal the problem in. Unglazed terracotta floor tiles and jaali work are treated the same way.

Concrete, render, pavers and grout

As a concrete water repellent, a penetrating sealer helps keep driveways, compound walls, parapets and pavers from darkening, staining and growing moss. New concrete must cure for at least 28 days first. It is not a substitute for below-ground waterproofing or for areas under constant water pressure, such as the inside of a tank.

What not to use it on

Glazed tiles, glass and sanitaryware have no open pores for it to enter. They need a surface coating instead; see our glass and ceramic coating guide. Surfaces that already carry a sealer, wax or curing compound must be stripped first.

How to tell whether a surface is ready to seal

Sprinkle a little water on a clean, dry area. If it darkens the surface and soaks in within a minute, the pores are open and the surface will take the sealer. If it beads, an old sealer or contamination is still there and must be removed first. Do this test in a few places on large jobs, because old coatings are often patchy.

How to apply it

Clean off dirt, oil, efflorescence, moss and old coatings, rinse, and let the surface dry for 24–48 hours.
Dilute 1 part Stone + Brick concentrate with 19 to 39 parts deionised water (1:19 to 1:39) and mix well.
Apply by low-pressure sprayer, brush or roller until the surface looks evenly wet, at about 70–100 ml of diluted product per m².
On dense or polished stone, wipe off any surplus within 10–15 minutes.
Apply one coat only. Once the first coat is water-repellent, a second cannot penetrate.
Keep foot traffic off for 6 hours and keep the surface dry for 24 hours. Full performance develops over about 5 days.

Work between 5 °C and 35 °C with no rain expected for 12 hours. In most of India that means sealing outside the monsoon, ideally in the dry months just before it, so walls and floors go into the rains protected.

How long it lasts

Because the protection sits inside the pores rather than on the surface, it is not worn away by foot traffic in the way a film is. Stone + Brick lasts up to 5 years, depending on exposure and how the surface is cleaned. Use pH-neutral cleaners; strong acids and alkalis shorten its life. When water starts to darken the surface again instead of beading, clean it and re-apply.

Frequently asked questions

Will a penetrating sealer change the look of my stone?

No. It leaves no gloss or film, so the colour and texture stay as they are. Always test a small, hidden area first to confirm on your particular stone.

Does it make stone waterproof?

It makes the surface water-repellent: rain and spills bead and run off instead of soaking in. It is not designed to hold back water under pressure, so it does not replace waterproofing membranes below ground or in tanks.

Can it be used on brick walls that already show efflorescence?

Yes, once the salts have been cleaned off and the wall has dried completely. Sealing a damp, salty wall traps the problem.

Who applies it?

Applicators, contractors and facility teams apply it with standard spray, brush or roller equipment. We supply the concentrate in trade quantities and help with the first job if needed.

Stone, brick and concrete sealing guide