The three sealing stages
Follow this sequence for every Marlborough Terracotta installation
1
Clean and prepare — before sealing
Tiles arrive with natural dust build-up from production and transport. Brush thoroughly with a stiff dry brush, then with a damp brush if needed. Allow tiles to dry completely — the clay softens when wet and is more fragile until dry.
For used or heavily soiled surfaces, use Sarsen Home Deep Clean diluted 1:10. Rinse well and allow 24 hours to dry before sealing.
2
Seal before laying — and seal the back too
Apply your chosen sealer to the face of the tile immediately before laying — and also to the back. Sealing the back is important: terracotta is so absorbent that an unsealed tile back can draw moisture from the adhesive and weaken the bond. Allow the sealer to absorb overnight before grouting.
Switch off underfloor heating before sealing and leave off for at least 24 hours after.
Buff off any surplus sealer still sitting on the surface after one hour — left to dry, it will harden patchy.
3
Seal again after grouting — to lock in full protection
Once grouting is fully dry, apply a second round of sealer over the entire surface including the grout joints. This is the stage that provides lasting stain resistance. Apply until the surface no longer soaks up the product immediately.
The surface may look fractionally darker after sealing — this is normal. Always test on a spare tile or inconspicuous area first.
Choose your finish
Natural / satin effect
Contemporary and low-odour. Protects against water, oil and grease while letting the tile breathe. Good for kitchens, bathrooms and busy areas. The easier route.
Products needed
Antique / oiled effect
Traditional method that deepens tone and builds a warm aged patina. Linseed oil saturates the clay; beeswax protects the surface and gives a gentle sheen. Interior use only.
Products needed
Indoor and outdoor suitability
Product
Interior
Exterior
Stain Block Eco
The only product here confirmed suitable for exterior use. Water-based and breathable — the recommended default for most installations.
Interior
Exterior
Stain Block
Interior use only. Solvent-based with stronger odour — for very high-porosity surfaces needing deeper penetration.
Interior
Not exterior
Stone Shield
Interior only. Do not use below freezing or in direct sunlight. Apply over Stain Block Eco on higher-porosity surfaces.
Interior
Not exterior
Boiled Linseed Oil
For terracotta tiles: interior use only. Also suitable outdoors on wood garden furniture and decking, but not for exterior tile installations.
Interior
Wood only
Beeswax Polish Antique
Interior only. Wax surfaces are not suitable for outdoor exposure or wet areas.
Interior
Not exterior
Stain Block vs Stain Block Eco — which do you need?
Stain Block Eco
Water-based — interior & exterior
Formula
Water-based impregnating sealer
Odour
Low — well-ventilated room sufficient
Outdoor use
Yes
Coverage (1L)
7.5–15m² on tile surfaces
Shelf life
2 years unopened
Best for
Most installations — recommended default
Stain Block
Solvent-based — interior only
Formula
Solvent-based (hydrocarbon / ethyl acetate)
Odour
Strong — good ventilation required; flammable
Outdoor use
No
Coverage (1L)
5–10m²
Shelf life
4 years unopened
Best for
Very high-porosity surfaces needing deeper penetration
All sealing products — full details
Natural route — step 1
Water-based impregnating sealer. Soaks into the tile body and repels water, oil and grease. Use before laying and again after grouting. Suitable indoors and outdoors.
Coverage: 7.5–15m² per litre
Coats: Apply hourly until saturated
Shelf life: 2 years
Coats: Apply hourly until saturated
Shelf life: 2 years
Natural route — step 2
Surface coating applied over Stain Block Eco. Builds a protective film giving a matt to satin finish. Do not shake before use. Interior only.
Coverage: 10m² per litre (textured)
Coats: Min 2, max 6
Fully resistant: 3 days after final coat
Coats: Min 2, max 6
Fully resistant: 3 days after final coat
Antique route — step 1
Impregnating oil that fills and hardens within the tile pores, enhancing the warm terracotta tone. Most tiles need 1–2 coats. Remove surplus within one hour. Interior only.
Coverage: 10–30m² per litre
Between coats: 12 hours minimum
Before waxing: 24 hours after final coat
Between coats: 12 hours minimum
Before waxing: 24 hours after final coat
Antique route — step 2
Soft paste wax applied over cured linseed oil. Builds an aged patina and protective layer. Apply with a cloth; buff to a shine. Apply second coat over grout joints. Interior only.
Coverage: 1 litre / 10m² (two coats)
Buff wait: 20 minutes after application
Keep dry: 3 days after final coat
Buff wait: 20 minutes after application
Keep dry: 3 days after final coat
Important notes
Suitable for
Interior floors — kitchens, hallways, living areas, orangeries
Interior walls (with appropriate adhesive)
Underfloor heating — commission before tiling; off during sealing
Exterior installations using Stain Block Eco only
New installations and refurbished surfaces
Do not
Seal over retained moisture — sealer will dry opaque or not cure
Use Beeswax, Linseed Oil or Stone Shield outdoors
Use Stone Shield below freezing or in direct sunlight
Leave linseed oil cloths dry — fire risk; soak in water before disposal
Apply Beeswax over partially cured or improperly sealed surfaces
Technical data sheets
Ongoing aftercare: Sweep regularly and clean with Sarsen Home Clean & Sheen — it cleans and reinforces the seal in one application. Refresh Stone Shield or re-wax as the surface shows signs of stain absorption. Every 3–4 years, use Deep Clean for a more intensive clean before re-sealing.