Stubborn stains on walls and ceilings can be a real headache — especially when a fresh coat of ordinary paint just makes them bleed right back through. The good news is that with the right primer and topcoat, you can permanently banish water marks, crayon scribbles, smoke stains, and more. Here's what you need to know before you pick up a brush.
Why Ordinary Paint Won't Always Cut It
Standard wall paints are designed to provide colour and a washable finish, not to seal in stains. Water-soluble stains (like watermarks from a roof leak) and oil-based stains (like crayon, nicotine, or grease) can bleed through multiple coats of regular paint if the surface isn't properly primed first. The key is using a stain-blocking primer before your topcoat.
Types of Stain-Blocking Primers
There are two main categories of stain-blocking primer available at NZ paint and hardware stores:
Shellac-Based Primers
- Best for: Severe water stains, smoke/nicotine, pet odours, ink, and heavy crayon marks
- Shellac-based primers (such as Zinsser BIN) are the gold standard for blocking stubborn stains
- They dry very quickly — often within 30–45 minutes
- They have a strong odour, so ventilate the room well and wear a respirator
- Clean up with methylated spirits
Water-Based Stain-Blocking Primers
- Best for: Light water marks, pencil, light crayon, general scuffs
- Products like Zinsser Bulls Eye 1-2-3 or similar water-based blockers are lower odour and easier to clean up
- Not always as effective on heavy oil-based stains or severe water damage
- Resene and Dulux both stock stain-blocking primers in their NZ ranges — ask in-store for the current options
Matching the Primer to the Stain
| Stain Type | Recommended Primer | Notes |
|---|---|---|
| Water marks / ceiling stains | Shellac or oil-based blocker | Fix the leak first! |
| Crayon | Shellac-based (e.g. Zinsser BIN) | Water-based may not fully block |
| Nicotine / smoke | Shellac-based | May need two coats |
| Grease / cooking splatter | Oil or shellac-based | Degrease surface first |
| Pencil / light scuffs | Water-based blocker | Usually one coat is enough |
| Mould stains | Mould-kill primer | Treat mould first — see below |
Step-by-Step: How to Cover Stains Properly
- Fix the source first. If you have a water mark, make absolutely sure the leak or moisture issue is resolved before painting. Painting over an active leak is a waste of time and money. If you suspect ongoing moisture, BRANZ has excellent guidance on diagnosing building moisture issues.
- Clean the surface. Wipe down the stained area with a damp cloth. For grease, use a sugar soap solution. Let it dry completely.
- Sand if needed. Lightly sand any raised or flaking paint edges with fine-grit sandpaper.
- Apply stain-blocking primer. Use a brush or small roller to apply the primer directly over the stain, extending slightly beyond the edges. One coat is often enough for shellac-based primers; water-based may need two.
- Let it dry fully. Follow the manufacturer's drying times — don't rush this step.
- Apply your topcoat. Use a quality interior paint in your chosen finish (flat/low-sheen for ceilings, low-sheen or semi-gloss for walls). Wattyl and Dulux both offer good washable interior ranges suited to NZ conditions.
- Two topcoats for best results. Especially over previously stained areas, two coats of topcoat will give you the most even, durable finish.
A Note on Mould Stains
Mould is common in NZ homes, particularly in older, poorly ventilated houses. Do not simply paint over mould — it will return and can spread. Treat the affected area with a mould killer first, then use a mould-resistant primer and paint. Under the Healthy Homes Standards, rental properties must have adequate ventilation, so if you're a landlord, address the root cause. For significant mould problems, consider getting a professional assessment.
Choosing the Right Topcoat Sheen
- Flat/matte: Hides surface imperfections well but harder to wipe clean — good for low-traffic areas
- Low-sheen/eggshell: The most popular choice for NZ living areas and bedrooms — washable and forgiving
- Semi-gloss/gloss: Very washable, ideal for kitchens, bathrooms, and kids' rooms where crayon is a repeat offender
For rooms with kids, a semi-gloss or low-sheen washable paint on walls means future crayon incidents are much easier to wipe off before they become a painting project.
When to Call a Professional
Some staining situations are best left to a qualified painter:
- Extensive water damage — if the plasterboard (GIB) is soft, stained deeply, or has lost its integrity, it may need replacing before repainting. Check GIB's technical information for guidance on damaged board.
- Widespread nicotine or smoke damage — whole-room shellac priming is a big, smelly job that professionals handle efficiently with the right equipment
- Mould covering large areas — this may indicate a deeper moisture or ventilation problem requiring expert assessment
- Heritage or textured surfaces — getting an even finish over complex surfaces takes skill
A professional painter will also know exactly which products work best for your specific situation. You can find qualified, local painters on tradedirectory.co.nz.