Tiling over painted walls is one of those jobs that seems straightforward but can go badly wrong if the groundwork isn't done properly. The short answer is: sometimes yes, but it depends heavily on the type of paint, the condition of the surface, and where in your home you're tiling. Get it wrong and you could end up with tiles popping off the wall within months — a costly and frustrating fix.
Why the paint type matters so much
Not all paint surfaces bond well with tile adhesive. The key issue is whether the adhesive can grip the wall firmly enough to hold the tile permanently — especially in wet areas like bathrooms and kitchens where moisture and temperature changes put extra stress on the bond.
- Flat or low-sheen water-based paint (common on plasterboard walls): Often acceptable if the paint is well adhered and in good condition.
- Gloss or semi-gloss paint: The smooth, hard surface is a poor base for adhesive. You'll need to sand it back thoroughly or remove it.
- Oil-based paint: Generally not suitable without significant preparation — adhesive struggles to bond to it.
- Textured or flaking paint: Must be removed entirely before tiling. Any loose material will cause tile failure.
If you're unsure what type of paint is on your wall, a simple test is to wet a small area — water-based paint will soften slightly, while oil-based won't.
Assessing the surface condition
Before you even think about adhesive, do a thorough inspection of the painted surface:
- Press and tap the wall — a hollow sound can indicate the paint or plaster beneath is delaminating.
- Try the tape test — press a strip of strong tape firmly onto the wall, then pull it off sharply. If paint comes away with it, the surface isn't stable enough to tile over.
- Check for moisture damage — bubbling, staining, or soft spots mean you have an underlying problem that tiling over will only make worse.
- Look for cracks — hairline cracks in plasterboard or plaster should be assessed; larger structural cracks need attention before tiling.
If the surface fails any of these checks, you'll need to strip the paint back or replace the substrate entirely.
Wet areas: special NZ Building Code requirements
In bathrooms, showers, and other wet areas, the stakes are much higher. The NZ Building Code — specifically clause E3 (Internal Moisture) — requires that wet area linings be durable and waterproof. Standard painted plasterboard is not an acceptable substrate for tiling in a shower or bath surround.
For wet areas, you should be using a tile-backer board or a waterproof-rated substrate such as GIB Aqualine or a cement-based board, with a proper waterproof membrane applied before tiling. Tiling over standard painted plasterboard in a shower is a common cause of water damage and mould — and it may not comply with the Building Code.
BRANZ provides excellent technical guidance on wet area construction that's worth reading before you start any bathroom tiling project.
How to prepare a painted wall for tiling
If your surface passes the checks above and you're tiling in a dry area (like a kitchen splashback), here's how to prepare it properly:
Cleaning
Wash the wall thoroughly with sugar soap to remove grease, dust, and grime. Rinse well and allow to dry completely.
Sanding
Sand gloss or semi-gloss surfaces with medium-grit sandpaper to create a mechanical key for the adhesive. Wipe away all dust.
Priming
Apply a bonding primer or sealer suitable for tiling. Products from Ardex or Mapei include primers specifically designed to improve adhesion on difficult surfaces — check the product data sheet to confirm suitability for your situation.
Choosing the right adhesive
Use a quality polymer-modified tile adhesive rated for wall tiles. Standard adhesives may not grip a painted surface adequately. Ask your tile supplier or a trade store like Mitre 10 or PlaceMakers for a product suited to your specific substrate.
Comparison: tiling over paint vs. stripping back
| Factor | Tile over paint | Strip paint / replace substrate |
|---|---|---|
| Time | Faster short-term | More work upfront |
| Cost | Lower initially | Higher initially |
| Risk of failure | Higher | Lower |
| Suitable for wet areas | Generally no | Yes (with correct substrate) |
| Long-term durability | Variable | Much better |
| Code compliance (wet areas) | Unlikely | Yes, if done correctly |
When to call a professional
While a competent DIYer can tile a dry area like a kitchen splashback, there are situations where you should bring in a qualified tiler:
- Any shower, bath surround, or wet area — waterproofing and substrate selection are critical and mistakes are expensive to fix.
- Large areas or complex layouts — getting tiles level and patterns aligned takes experience.
- If you find moisture damage or structural issues — these need a builder's assessment first.
- If you're unsure about Building Code compliance — a licensed tiler will know what's required.
A qualified tiler will also be able to advise whether your existing painted surface is worth working with or whether it's better to start fresh. You can find experienced local tilers on tradedirectory.co.nz.
Note on plumbing and electrical work: If your tiling project involves moving or installing plumbing (e.g. shower fittings, tapware) or electrical fittings (e.g. heated towel rails, extractor fans), these are restricted trades in New Zealand. Plumbing work must be carried out by a licensed tradesperson registered with the Plumbers, Gasfitters and Drainlayers Board, and electrical work must be done by a registered electrician through the Electrical Workers Registration Board.