Question: My walls look bumpy under sidelight. Old patches and plaster ridges show through the new paint. Do I need a full skim, or just more paint?
Answer: Paint does not hide bumps. Filler is for spot repairs. A skim coat is a 2–3 mm full-wall thin plaster layer that gives a flat, premium finish. Very uneven walls may need more than one coat. After curing, the wall is sanded, sealed and then painted.
This is an uneven surface problem. If the skim is peeling off, see peeling skim coat. If the film is cracking in hairlines, see paint cracking hairline walls.
Why Walls Look Bumpy
- Old textured paint or plaster ridges.
- Uneven original wall.
- Multiple paint layers building up unevenly.
- Repair patches that were never smoothed.
Skim Coat vs Filler
| Job | Use |
|---|---|
| One hole or crack | Filler |
| Whole wall looks wavy under sidelight | Full-wall skim |
| Premium flat modern finish | Skim, then paint |
| Old rental refresh | Often a full-room skim |
What the Work Involves
- Sand rough areas.
- Apply a 2–3 mm skim (more layers if the wall is very uneven).
- Sand after curing.
- Prime with sealer before painting.
Skim-coat work carries the 12-Month Smoothness & Adhesion Warranty.
Costs in KL and Selangor
Published problem rate is RM 5 to RM 12 per sq ft. KL Servis Rumah publishes wall skim coating from RM 5 per sq ft, ceiling skim coating from RM 6 per sq ft, crack and joint repair from RM 22 per linier ft, and a full condo re-skim package from RM 4,200. Local body copy also cites RM 400 to RM 1,200 for one room depending on area and unevenness.
See the service overview at wall and ceiling skim coat.
Related Problems
- Peeling skim coat — the skim is detaching.
- Hairline cracks on painted walls — film cracks, not waviness.
- Yellowing white walls — colour shift on a flat wall.
Frequently Asked Questions
Is skim coat different from filler?
Yes. Filler is for spots. Skim coat is a full-wall thin plaster layer.
How thick is a skim coat?
Standard is 2 to 3 mm. Very uneven walls may need multiple layers.
Can I skip skim if I am repainting?
You can, but paint alone does not hide bumps. Premium finishes start with a proper skim.
Flatten the Wall, Then Paint
If sidelight shows every ridge, another topcoat will show them too. KL Servis Rumah provides skim coat services across Kuala Lumpur and Selangor.
Send a sidelight photo of the worst wall — WhatsApp our skim team.