Owner, Procover Painting · 14+ years painting · NSW Licence #392662C · 10 min read
Key takeaways
- Keep a wet edge. Roll one wall at a time and never roll back into paint that has started to dry.
- Match the roller to the paint and the wall. Dulux suggests 10 to 12 mm for low sheen and flat paint on walls, and 6 to 8 mm for gloss and semi-gloss.
- Prep matters. Wash, sand any gloss, fill, and spot-prime repairs so the wall soaks up paint evenly.
- Already patchy? Let it dry fully, sand any ridges lightly, spot-prime, then repaint the whole wall from corner to corner.
Quick answer: why does my paint look patchy?
Most patchy walls come from rolling into paint that has already started to dry, using the wrong roller cover, loading the roller badly, or painting over a surface that soaks up paint unevenly. Harsh light can also make a good job look patchy.
It helps to know which problem you have, because the fix is different for each.
Darker or shinier bands
Strips of denser colour or higher gloss where wet and dry paint overlapped.
A textured pattern
Also called stipple. It is the pattern the roller leaves behind. Often it is the wrong cover, a cheap roller or too much paint.
Uneven sheen
Patches that look shinier or duller than the rest, even though the colour matches. Common over repairs and porous spots.
The main causes of patchy paint
No wet edge
You roll fresh paint over a section that has already started to dry.
Wrong roller nap
The cover does not suit the surface texture or the type of paint.
Too much or too little paint
An overloaded roller leaves ridges. An under-loaded one leaves thin, see-through areas.
Poor prep
Shiny, dirty or porous patches underneath soak up or reject paint differently.
Bad timing
Direct sun, strong wind or heat can dry paint too fast. High humidity can keep it tacky for longer.
Harsh lighting
Downlights and low sun show up every ridge and sheen change.
Before you paint: a 7-step checklist
Most patchy jobs are lost before the first coat goes on. Run through these steps before you open the tin.
- Check the wall in side light.Hold a work light or phone torch close to the wall. Look for ridges, shiny patches and old roller lines.
- Wash off grease and grime.Clean around switches, doors and cooking areas with sugar soap. Rinse with clean water and let it dry.
- Sand glossy or rough spots.Lightly scuff any shiny enamel or semi-gloss. Feather out old filler until you can’t feel a hard edge.
- Fill gaps and holes.Use a flexible gap filler along skirting boards and architraves. Use a patching compound for dents and cracks in plaster.
- Spot-prime problem areas.Prime bare plaster, patches, stains and water-damaged spots. This evens out how the wall soaks up paint.
- Check the spread rate.Find the recommended square metres per litre on the tin. Stretching a tin well past that is a common cause of patchy coverage.
- Plan the order of rooms.Start with easier rooms. Leave big feature walls and stairwells until your technique is solid.
Sanding old paint in a home built before 1970?
Treat it as lead paint until you know otherwise. Never dry sand it. Read the lead paint section in our oil vs water-based paint guide, and the NSW LeadSmart advice, before you start.
Keep a wet edge: your best defence against lap marks
The wet edge is the strip of paint you have just rolled that is still wet. You keep rolling into it, so each new strip blends in before the paint starts to dry.
Lose it and you get dark or shiny bands, obvious stop-start marks, and uneven colour, especially in darker tones.
How to keep a wet edge
- Paint one wall at a time.Cut in and roll that wall fully before you start the next.
- Cut in small sections.Brush the ceiling line, skirting and corners only as far ahead as you can roll before the brushed paint dries. In our experience, that is about 1 to 1.5 metres.
- Load the roller evenly.Roll it on the tray ramp until it looks evenly wet, with no drips.
- Lay the paint on in a W.Roll a W shape, then fill it in. Leave a small gap at the edges to tidy up later.
- Roll back into the wet edge.Start on the unpainted wall a short distance from the wet strip, then roll back into it. Don’t start in the middle of a wet patch and roll outwards.
- Finish with light strokes.Run the roller from ceiling to skirting in one pass without stopping.
- Move to the next strip straight away.Don’t stop to answer calls or check your phone mid-wall.
- Leave half-dry paint alone.If you missed a spot, wait until the coat is fully dry and fix it on the next coat.
Pick the right roller nap
The nap is the thickness of the roller cover’s pile. Using the wrong one is like mowing a lawn at the wrong height. You can do it, but it won’t look right. Here is a guide for common Australian jobs.
| Surface or paint | Nap | Notes |
|---|---|---|
| Doors and trims in gloss or semi-gloss | 6 to 8 mm | Use light final passes so the finish doesn’t pebble. |
| Smooth walls in low sheen or flat paint | 10 to 12 mm | Suits most plasterboard walls. |
| Ceilings in flat ceiling paint | 10 to 12 mm, up to 15 mm | A slightly longer nap helps with overhead work and small bumps. |
| Rough plaster, brick, render or concrete | 20 mm or more | Dulux lists 20 to 32 mm for rough surfaces. A longer nap reaches into the texture. |
A short nap on a rough wall can leave pale speckles in the low spots. A long nap on a smooth wall can leave heavy texture and thick bands. Microfibre covers shed very little lint, which is handy on walls and ceilings.
When to replace a roller cover
A worn roller can cause patchy coverage even with good technique. Replace the cover if:
- The nap looks flattened or matted.
- It leaves a different texture on each pass.
- You see repeating lines that match the roller ends.
For a big job, buy more than one cover.
How much paint is enough?
Overloading and under-loading the roller both leave streaky finishes.
Too little paint
- You can still see the old colour or undercoat lines.
- The roller sounds dry or scratchy.
- You have to push hard to get coverage.
People often over-roll to stretch the paint, which can create more lap marks.
Too much paint
- The roller splatters when you lift it.
- Thick ridges form where you stop or change direction.
- You see sags or curtains on the wall.
To find the right balance, follow the spread rate on the tin (square metres per litre). Measure your wall area, and aim to use close to the recommended amount for each coat.
You can also buy a wet film gauge from a paint store. It is a small comb-shaped tool you press into fresh paint to check the thickness. Professionals use it to keep coverage even.
Weather, humidity and drying time in Newcastle
Our coastal climate is great for living, but it can be tough on paint. High humidity slows drying, so paint stays tacky for longer and is easier to disturb. Direct sun or strong wind can do the opposite and dry paint too fast. Follow the temperature and humidity limits on the tin.
Humid summer afternoons
Paint stays tacky for longer. It is easier to disturb half-dry paint and leave lap marks.
Hot, sunny or windy walls
Paint can dry before you reach the next strip. That makes a wet edge hard to keep.
Cold walls and sudden changes
A quick temperature drop can cause condensation on cold walls, which can leave streaks in fresh paint.
Weather timing checklist
- Check the forecast.Avoid days with extreme humidity or heavy rain, especially for exterior walls. Painting outside near the coast? Wash salt off first.
- Pick the time of day.For interiors, aim for mid-morning or late afternoon rather than the hottest part of the day.
- Keep the air moving.Use air-con or gentle fans. Don’t force-dry paint with high heat or strong dehumidifiers.
- Respect recoat times.If the tin says 2 hours at 25°C and 50% humidity, add time when it is cooler or wetter.
Light, sheen and “phantom” patchiness
Sometimes the paint is fine, but the light makes it look patchy. Light that hits the wall at a shallow angle, from windows or downlights, makes tiny roller ridges throw long shadows. Mixed sheen from touch-ups shows as shiny or dull patches.
It is common in hallways with downlights close to the walls, feature walls near big windows, and coastal homes where low sun hits one wall at dawn or dusk.
Use a lower sheen
Flat and low-sheen paints hide minor roller marks better than higher sheens.
Plan the lighting
When renovating, keep downlights away from walls. Wider beam angles and softer light are kinder to imperfect walls.
Paint with a work light
Hold a torch or work light close to the wall at a low angle. Fix ridges while the paint is still wet.
How to fix patchy paint that has already dried
Spot touch-ups rarely work. A fresh dab over dry paint often leaves a new patch, usually a different sheen. For a good result, fix the cause, then repaint the whole wall.
- Let the paint dry fully.Check the recoat and cure times on the tin. Don’t sand or recoat tacky paint.
- Work out the problem.Check the wall in side light. Are you seeing ridges, a sheen difference or uneven colour?
- Sand ridges lightly.Use fine sandpaper, then wipe off the dust. Skip this step if the surface is smooth.
- Spot-prime patches.Prime filler, repairs and stains so they stop soaking up paint differently.
- Repaint the whole wall.Go corner to corner with the right roller nap, a lightly loaded roller and a wet edge. Don’t stop partway across.
- Check in side light again.If you can still see bands after the next coat is dry, the cause is usually the prep or the paint, not the roller.
Sand lightly, then repaint the full wall with a wet edge.
Sand them smooth, wipe off the dust, then recoat with the right nap.
Spot-prime the repair, then repaint the whole wall.
Frequently asked questions
Most likely you rolled back into half-dry paint and lost the wet edge. Other common causes are a roller nap that doesn’t suit the surface, patches that weren’t primed so the wall absorbed paint unevenly, and painting in poor conditions, such as very humid, hot or windy weather.
Use a 10 to 12 mm nap and quality flat ceiling paint. Work in strips across the shortest direction of the room and keep a wet edge without stopping mid-ceiling. Paint when the room is cooler, not at the peak of a humid day. Two normal coats work better than one heavy coat.
The roller nap may have been wrong both times, or the same technique errors were repeated, such as no wet edge or over-rolling. Harsh light can also reveal every ridge, and old texture or unprimed patches may need extra prep. Sand lightly, spot-prime, and recoat the whole wall with corrected technique, or call a painter.
Usually not. A small touch-up over dry paint often shows as a different sheen. It is better to repaint the whole wall from corner to corner so the finish blends in.
Spot-prime anything that will soak up paint differently, such as bare plaster, filler, patches, stains and water-damaged spots. A good primer evens out how the wall absorbs paint. Follow the instructions on the tin.
Follow the recoat time on the tin. For example, a tin might say 2 hours at 25°C and 50% humidity. Add time if it is cooler or more humid.
DIY or hire a painter in Newcastle?
Plenty of Australians paint their own homes. A 2023 hipages survey of homeowners found that 40% had tried DIY repairs or renovations to save money, and 29% had to hire a professional after a DIY attempt went wrong. The average cost to fix a DIY error was $4,608. Those numbers come from a survey of homeowners, so treat them as a guide.
Not every job is worth doing yourself.
DIY is a good fit when
- The rooms are small and easy to reach.
- You have time to learn and fix mistakes.
- You are happy with “very good” rather than “perfect”.
Hiring a painter makes sense when
- You have large open walls where streaks show.
- Ceilings are high or over stairwells.
- You are using deep colours or feature walls.
- You live near the coast and want advice on products for salt, humidity and harsh sun.
- You don’t have time to experiment.
Summary: key steps to avoid patchy paint
Here is a simple list to stick on the wall before you start.
- Prep first.Wash, sand, fill and spot-prime. Check the wall in side light.
- Pick the right roller nap.10 to 12 mm for most walls and ceilings. Shorter for gloss doors, longer for rough surfaces.
- Load the roller properly.Roll off the excess and follow the spread rate on the tin.
- Keep a wet edge.Work in strips and roll back into the previous wet strip.
- Don’t touch up half-dry paint.Wait until the coat is fully dry.
- Respect the weather and recoat times.Avoid extreme humidity and heat, and give extra drying time on damp or cool days.
- Watch the light.Use a work light to check for ridges, and pick a sheen to suit the wall.
Want streak-free walls without the hassle?
Procover Painting is a local team servicing Newcastle, Maitland, Port Stephens, Lake Macquarie and the Hunter Valley. We do full interior and exterior repaints with careful prep, so patchy coverage never gets started. Send us a few photos for a free, no-obligation quote.
Sources and further reading
- Dulux, How to use a paint roller (nap sizes by paint type and surface).
- Dulux, Interior paint lapping (what lap marks are).
- Dulux New Zealand, Roller marks and stipple (what roller marks are).
- Benjamin Moore, How to prevent paint lap (wet edge, causes of lap marks).
- Monarch Painting Supplies, How to choose the right roller (ceiling nap range).
- Inspirations Paint, Roller covers: the unsung heroes of painting (walls and ceilings, microfibre).
- The Property Tribune, hipages report on homeowner DIY and small fix-ups (survey, May 2023).
- NSW Government, LeadSmart: renovating and maintenance.
Last reviewed 19 October 2026. Product details and figures were checked against the pages listed above. Always read the label on your paint before you start.
