Blackfriar Interior Seal Damp Protects Walls from Moisture

Manufactured by Blackfriar

Blackfriar Interior Seal Damp is a professional-grade, solvent-based sealer that protects interior walls from damp patches, stains, and moisture ingress. Ideal for use before decorating, it prepares plaster, brick, and cement surfaces by forming a durable, breathable barrier that locks in moisture while remaining compatible with paint and wallpaper finishes.

This interior damp seal helps prevent water marks, discolouration, and surface degradation caused by rising or penetrating damp. Its fast-drying formula allows quick recoating, making it perfect for DIY and professional applications.

Unlike standard primers or paints, Blackfriar Interior Seal Damp is engineered explicitly for moisture-prone areas, ensuring your interior decoration stays fresh and long-lasting. The low-odour, easy-to-apply formula can be brushed or rolled on to give an even, effective protective layer.

Key Features & Benefits

Protects walls from damp: Locks in moisture and prevents unsightly stains.
Versatile application: Suitable for plaster, brick, and cement surfaces.
Pre-decoration ready: Paintable or paperable after curing for hassle-free finishing.
Fast drying: Touch dry in 2–4 hours with recoatable time in 16 hours.
Durable barrier: Forms a breathable seal that allows vapour to escape while preventing moisture penetration.
Professional and DIY friendly: Easy application with brush or roller.
Solvent-based: Provides a robust, long-lasting protective layer.

Ideal Uses

Interior walls and ceilings affected by damp patches
Plaster, brick, or cement surfaces before painting or wallpapering
Rooms prone to minor moisture ingress, such as kitchens, bathrooms, or basements
New or older walls requiring preparation against damp discolouration

Sizes & Coverage

Pack Size: 2.5 L
Coverage: Approximately 12 m² per litre, depending on substrate porosity and texture

Blackfriar Interior Seal Damp is essential for anyone looking to secure interior surfaces against damp before applying decorative finishes. It provides long-lasting protection and peace of mind.

Surface Preparation

Clean surface: Remove dust, loose paint, wallpaper residues, grease, and dirt before application.
Repair: Fill cracks or holes and smooth rough patches for a uniform finish.
Drying: Ensure walls are free from standing water; dampness from minor moisture is acceptable.

Mixing

Stir the product thoroughly before use to ensure consistent performance.
Do not dilute; use directly from the tin for best results.

First Coat

Application: Apply evenly using a brush or roller. Work in manageable sections to avoid lap marks.
Coverage: Approx. 12 m² per litre, depending on substrate porosity.

Recoating

Time: Allow 16 hours before recoating or applying paint or wallpaper.
Light touch: Ensure the first coat is touch dry (2–4 hours) before recoating.

Curing & Reopening

Light traffic: Safe to touch after 2–4 hours.
Complete protection: Achieved after 24–48 hours.
Keep surfaces protected from excessive water or condensation until fully cured.

Clean-Up

Wash brushes and rollers immediately with warm, soapy water.
Dispose of empty containers and leftover product responsibly according to local regulations.

Pro Tips

Apply in thin, even layers to prevent pooling or streaking.
Use adequate ventilation in enclosed spaces to aid drying and reduce solvent odour.
For heavily damp walls, multiple coats may improve barrier performance.

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Frequently Asked Questions

What is Blackfriar Interior Seal Damp used for?

It protects plaster, brick, and cement interiors from damp patches before painting or wallpapering, preventing stains and preparing the wall for decoration.

Can I apply it to wood?

No, it is not suitable for wood; use only on plaster, brick, and cement.

Do I need to remove existing paint before applying?

Yes, remove loose or flaking paint, dust, and dirt to ensure adhesion.

Can I use it on wet walls?

It can be applied to slightly damp walls, but not to walls with standing water.

How should I apply Interior Seal Damp?

Apply evenly with a brush or roller in manageable sections for full coverage.

How much coverage does 1 litre provide?

Around 12 m² per litre, depending on surface porosity.

How long does it take to dry?

Touch dry in 2–4 hours, recoatable or paintable after 16 hours.

How many coats are needed?

Usually one coat, but two may be needed on porous or heavily damp walls.

Can I paint or wallpaper over it?

Yes, once fully cured it provides a stable base for paint or wallpaper.

How should I clean brushes and rollers?

Wash immediately with warm, soapy water while still wet.

Is it safe to use in poorly ventilated areas?

Ensure good ventilation as it is solvent-based and produces fumes.

Does it permanently fix damp issues?

No, it only blocks stains; underlying causes like leaks or rising damp must be fixed.

Can it be used in bathrooms or kitchens?

Yes, in condensation-prone areas, but it is not a full waterproofing solution.

What precautions should I take during application?

Wear gloves, avoid skin/eye contact, and keep children and pets away until dry.

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£32.99 (inc VAT)

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Size

2.5LTR

Product variants

*subject to stock levels at the time of your order.

Blackfriar Interior Seal Damp Protects Walls from Moisture

Key Features & Benefits

Ideal Uses

Sizes & Coverage

Frequently Asked Questions

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