SPO Shellac Stain & Odour Blocker: The Ultimate Guide to Blocking Stains & Odours

Why Ordinary Paint Can't Block Stubborn Stains and Odours

If you've ever tried painting over water stains, smoke damage or nicotine-yellowed walls with ordinary emulsion, you'll know the frustration—the stains bleed straight through, ruining your finish and wasting your time and money. Standard primers simply aren't designed to handle severe staining or lock in persistent odours like smoke, pets or damp.

Whether you're dealing with water damage from leaks, smoke-stained walls from fires or smoking, nicotine yellowing, pet odours, graffiti or tannin bleed from wood knots, you need a specialist primer that creates an impenetrable barrier between the problem and your topcoat.

The Professional Solution: SPO Shellac Stain & Odour Blocker

SPO Shellac Stain & Odour Blocker is a heavy-duty shellac-based primer that banishes stubborn water marks, smoke damage and lingering smells so your topcoat looks perfect first time and stays that way. Formulated by Specialist Paints Online's chemists for professional-grade adhesion, this is the go-to primer decorators trust when nothing else works.

Key Benefits That Save Time and Money

• Stain-Free Finish Fast – Stops even severe water marks, smoke damage and tannin bleed re-appearing, guaranteeing a pristine topcoat
• Lasting Results – Rock-hard shellac film grips any paint and resists future staining, so walls stay perfect for years
• Cost-Effective Solution – One primer, one coat beats costly renovations and multiple coats of finish paint, cutting labour and material spend
• Fresh-Smelling Rooms – Powerful odour blocker traps smoke, pet and damp smells, leaving spaces ready to enjoy
• Same-Day Completion – Touch-dry in 15 minutes and recoatable in 45 minutes; prime and paint before lunch
• Professional Adhesion – Grips to virtually any surface including glossy finishes, tiles and problem substrates

What Stains and Odours Does It Block?

SPO Shellac Stain & Odour Blocker is your solution for the toughest staining and odour problems:

Stains It Blocks

• Water Stains – From leaks, floods, burst pipes or roof damage
• Smoke & Fire Damage – Soot, smoke staining and fire-damaged surfaces
• Nicotine Staining – Yellow-brown stains from cigarette or cigar smoke
• Tannin Bleed – Brown stains from wood knots bleeding through paint
• Graffiti & Marker Pens – Permanent markers, spray paint and graffiti
• Rust Stains – Rust bleeding through from metal fixtures
• Crayon & Pencil Marks – Children's artwork on walls
• General Staining – Coffee, wine, food stains and general discolouration

Odours It Blocks

• Smoke Odours – From fires, cigarettes or cigars
• Pet Odours – Urine, general pet smells
• Damp & Mould Smells – Musty odours from water damage
• Cooking Odours – Persistent food smells absorbed into walls
• General Mustiness – Old building smells and stale air

What You Need to Buy: Complete Shopping List

To successfully block stains and odours, here's everything you'll need:

Essential Products

• SPO Shellac Stain & Odour Blocker – Available in 500ml (£12.99), 1L (£19.99), 2.5L (£45.00) and 5L (£99.99)
• Paint Roller & Tray – For efficient application on large areas
• Paintbrush (2-3 inch) – For edges, corners and detailed areas
• Dust Sheets – To protect floors and furniture
• Masking Tape – To protect adjacent surfaces

Recommended Preparation Products

• Fluxaf Mould & Mildew Stain Remover – If you have mould, clean it before priming
• Clean Cloths – For wiping down surfaces

Topcoat Paint

• Your Choice of Emulsion or Gloss – SPO Shellac works under any topcoat paint

How Much Do You Need? Coverage Calculator

SPO Shellac Stain & Odour Blocker covers approximately 10-12 square metres per litre depending on surface porosity and stain severity. Here's a quick guide:

• Small area (single wall, 3m x 2.5m) – 500ml-1L will cover with one coat
• Medium room (two walls, 6m x 2.5m) – 1-2L will cover with one coat
• Large room (full room, 12m x 2.5m) – 2.5-5L for one coat
• Ceiling (3m x 4m) – 1L will cover with one coat
• Severe staining – May require two coats, so double your quantity

Top tip: For severe water stains or heavy smoke damage, you may need two coats for complete blocking. Always buy slightly more than you calculate to ensure complete coverage.

Step-by-Step Application Guide

Step 1: Assess and Prepare

Identify the type and severity of staining or odour. If you have active mould growth, clean it first with Fluxaf Mould & Mildew Stain Remover and allow to dry. Remove any loose, flaking paint or debris.

Clean the surface to remove grease, dirt and grime. Rinse with clean water and allow to dry. The surface should be clean and dry before priming.

Step 2: Protect Surrounding Areas

Use masking tape to protect adjacent surfaces, skirting boards and fixtures. Lay dust sheets to protect floors and furniture. Good preparation saves cleanup time later.

Step 3: Apply SPO Shellac Stain & Odour Blocker

Stir the primer thoroughly before use. Using a brush or roller, apply a generous, even coat directly over the stained or odorous surface. Don't thin the product—use it straight from the tin for maximum blocking power.

Pay particular attention to heavily stained areas, ensuring complete coverage. The primer will appear white/cream and should completely cover the stain in one coat. For severe staining, you may need a second coat.

Step 4: Drying Time

SPO Shellac Stain & Odour Blocker is incredibly fast-drying:

• Touch-dry – 15 minutes
• Recoatable – 45 minutes
• Fully cured – 2-4 hours

This means you can prime in the morning and apply your topcoat before lunch, completing the entire job in a single day.

Step 5: Apply Second Coat (If Needed)

For severe water stains, heavy smoke damage or persistent odours, apply a second coat after 45 minutes. Two coats provide maximum blocking power for the toughest problems.

Step 6: Apply Topcoat

Once the primer is dry (45 minutes minimum), you can apply your chosen topcoat paint. SPO Shellac Stain & Odour Blocker works under any paint type—emulsion, gloss, eggshell or specialist finishes. The stain-blocking barrier is now permanent, and your topcoat will look perfect.

Professional Tips for Perfect Results

• Don't thin the product – Use it straight from the tin for maximum blocking power
• Ensure good ventilation – Shellac-based primers have a stronger odour than water-based paints; open windows during application
• Clean brushes with methylated spirits – Shellac requires solvent cleaning, not water
• Test severe stains – On very severe staining, test a small area first to confirm one coat is sufficient
• Work quickly – Shellac dries fast, so work in manageable sections  Don't keep the lid off as a skin will form. if you leave brushes and rollers between coats without cleaning these will also dry out
• Store properly – Keep the lid tightly sealed to prevent the primer from drying out

Common Questions Answered

Will it really block water stains permanently?

Yes, SPO Shellac Stain & Odour Blocker creates a permanent barrier that prevents water stains from bleeding through. Once sealed, the stains cannot re-appear through your topcoat.

Can I use it on ceilings?

Absolutely. It's ideal for ceiling water stains from leaks or roof damage. The fast-drying formula means less dripping and quicker completion.

Does it work on smoke-damaged walls?

Yes, it's specifically formulated to seal smoke and fire damage, blocking both the staining and the odour. It's widely used in fire restoration work.

How do I clean my brushes?

Clean brushes and rollers with methylated spirits or white spirit immediately after use. Shellac-based primers cannot be cleaned with water.

Can I paint over gloss with it?

Yes, SPO Shellac Stain & Odour Blocker has excellent adhesion to glossy surfaces, making it perfect for priming over old gloss paint before applying emulsion.

Will it stop pet odours?

Yes, it effectively seals in pet odours including urine smells. However, if the source of the odour is still present (e.g., urine-soaked carpet), you'll need to remove that first.

Where to Use SPO Shellac Stain & Odour Blocker

This versatile primer works throughout your property:

• Water-Damaged Rooms – After leaks, floods or burst pipes
• Fire-Damaged Properties – Restoration after smoke and fire damage
• Smoker's Homes – Removing nicotine staining and odours
• Rental Properties – Quick turnaround between tenancies
• Bathrooms & Kitchens – Blocking water stains and odours
• Children's Rooms – Covering crayon, marker and general marks
• Pet-Affected Areas – Sealing pet odours and stains
• Woodwork – Blocking tannin bleed from knots
• Commercial Spaces – Shops, offices, hotels needing fast restoration

Complete Your Stain-Blocking System

For the most effective stain and odour blocking, use these complementary products:

• Fluxaf Mould & Mildew Stain Remover – Clean mould before priming
• SPO General Purpose Stain Block Primer – For lighter staining that doesn't need shellac strength
• Quality Brushes & Rollers – Professional application tools for the best finish
• Methylated Spirits – For cleaning brushes after use

Why Choose SPO Paint?

SPO (Specialist Paints Online) is our own brand, developed by our in-house chemists and manufactured right here in the UK. Every product is formulated specifically for the challenges of UK homes and professional decorators. When you choose SPO, you're getting professional-grade performance at exceptional value, backed by expert technical support and next-day UK delivery.

Order Today, Transform Tomorrow

Don't let stubborn stains and odours ruin your decorating. With next-day UK delivery, you can order SPO Shellac Stain & Odour Blocker today and transform problem surfaces tomorrow.

Available in four sizes:

• 500ml – £12.99 (covers 5-6 square metres)
• 1L – £19.99 (covers 10-12 square metres)
• 2.5L – £45.00 (covers 25-30 square metres)
• 5L – £99.99 (covers 50-60 square metres)

Order before midday for next-day UK delivery. Prime, paint and finish faster—create perfect walls in record time.

Need expert advice? Our technical team is here to help you calculate quantities, choose the right preparation products and answer any questions about blocking your specific stains or odours. Get in touch today for personalised recommendations.

Related Products: Fluxaf Mould & Mildew Stain Remover | SPO General Purpose Stain Block Primer | SPO Anti-Condensation Paint