Granite is one of the most durable natural stones available, but it is not completely maintenance-free. Properly maintained and sealed granite countertops will last a lifetime and retain their mirror polish for decades. This guide is written for both stone distributors advising their customers and end users managing their own granite installations.
Why Granite Needs Sealing
Despite its density and hardness, granite is a naturally porous stone. The degree of porosity varies significantly between varieties — Absolute Black and DR Black have near-zero porosity, while lighter granites like Kashmir White and Viscount White have higher porosity and absorb liquids more readily.
An unsealed or under-sealed granite surface can absorb oils, acids and coloured liquids, causing permanent staining that cannot be polished out without re-processing.
Daily Cleaning: What to Use and What to Avoid
Use:
- Warm water and a few drops of pH-neutral dish soap
- Microfibre cloths (avoid abrasive cloths or scouring pads)
- Specialist granite cleaning sprays (pH 7 formulations)
Never Use:
- Vinegar, lemon juice or other acids — they etch and dull the surface
- Bleach or ammonia-based cleaners — they break down sealant
- Abrasive powder cleaners — they scratch the polish
- Generic household sprays (most are too acidic or alkaline)
How Often to Re-Seal
| Granite Variety | Porosity Level | Re-sealing Frequency |
|---|---|---|
| Absolute Black, DR Black | Very Low | Every 3–5 years |
| Black Galaxy, Coffee Brown | Low | Every 2–3 years |
| Steel Grey, Tan Brown | Medium | Every 1–2 years |
| Kashmir White, Viscount White | Medium–High | Every 12 months |
| Thunder White, Ivory Brown | High | Every 6–12 months |
Step-by-Step Sealing Process
- Clean the surface thoroughly — remove all grease, residues and cleaning products. The surface must be completely dry before sealing.
- Choose the right sealant — use a penetrating impregnating sealer, not a topical coating. Impregnating sealers penetrate the stone without changing its appearance.
- Apply the sealant evenly — use a clean microfibre cloth or applicator pad. Apply in small sections.
- Allow penetration time — typically 5–15 minutes depending on the product and stone porosity.
- Buff off excess — before the sealant dries, buff away any excess with a clean cloth. Never allow excess sealant to dry on the surface — it will leave a hazy residue.
- Allow full cure time — most sealants require 24–48 hours before the surface can be used normally.
Removing Common Stains
| Stain Type | Treatment |
|---|---|
| Oil-based (cooking oil, grease) | Apply cornflour or talcum powder, leave overnight to absorb, then clean with pH-neutral soap |
| Organic (coffee, wine, tea) | Hydrogen peroxide (12%) applied to the stain for 30 minutes, then rinse |
| Rust stains | Specialist granite rust remover — do not use general rust removers which contain acid |
| Ink or paint | Acetone applied carefully with a cotton ball — test in an inconspicuous area first |