How to touch up damaged walls: filling holes, dents and marks

After years of living in a home you see them everywhere: holes from old picture hooks and plugs, a dent where the door handle hits the wall, a scratch from a chair or a mark you can no longer remove. Touching up walls is a classic job that gets left undone. Yet it is a nice indoor job for an autumn weekend. On Saturday you fill and sand, and in between or on Sunday you touch up the paint. In this blog you will read how to do that without visible patches or edges afterwards.

👷 Calling in a professional is never unnecessary. Large cracks, loose plaster, damp patches or mould often point to a deeper problem. Have that assessed by a plasterer or, in the case of damp, a building surveyor. If you suspect asbestos in old wall or ceiling finishes, do not sand or drill and call in a certified company.

What do you need?

• A Japanese filling knife for small holes and a putty knife with aluminium blade for larger areas.
• lightweight filler: light, shrinks little and is easy to sand.
• A sanding block grit 120 to sand back and a sanding block grit 220 for the final smooth finish.
• An acrylic brush and a small foam roller with a paint tray to touch up the paint. Preferably use some leftover of the same wall paint.
• blue painter's tape to mask skirting boards and frames, and masking film for the floor.
• A rechargeable LED work lamp: with raking light from the side you can see every irregularity.
• A construction vacuum cleaner to clean up sanding dust.
• A sturdy wooden painter ladder for higher spots.
• PPE: work gloves with nitrile coating, safety goggles and an FFP2 dust mask when sanding.

Step-by-step plan

1. Clear the wall and cover up. Remove hooks, nails and old plugs. Put masking film on the floor and mask the skirting boards. Read more about masking in our blog on masking tape and protective film.
2. Inspect the wall with raking light. Hold the work lamp at an angle along the wall and make a light pencil mark next to each spot.
3. Clean the spots. Remove loose edges with the putty knife and wipe away dust and grease. Wipe a greasy mark first with a damp cloth and a little cleaner.
4. Fill the holes. Press the filler firmly into the hole with the Japanese filling knife and scrape off the excess in one movement. Two thin layers are better than one thick one.
5. Let it dry according to the packaging. Fill deep holes in layers and let them dry in between.
6. Sand flush. Sand first with grit 120 and then with 220, until you can no longer feel a transition with your fingertips. Vacuum up the sanding dust.
7. Prime the spots. First give the filled spots a thin coat of paint, otherwise they will show as dull patches later.
8. Touch up the paint. Roll outwards from the spot with little paint on the roller, so the edge blends in. On a large or older wall it often looks better to repaint the whole surface from corner to corner.

💡 Touch-ups are least noticeable if you use the same sheen and the same colour. If you no longer know which paint was used, paint the whole wall. How to do that is explained in our blog on painting a wall.

Common mistakes

• Filling too thickly, so the spot sags or cracks.
• Sanding or painting too early, while the filler is still wet.
• No primer coat on the filled spots, so they stay dull.
• Touching up with a fully loaded roller, which leaves a hard edge.
• Simply smearing over large cracks without looking for the cause.

Working safely

You do not want to inhale sanding dust: wear an FFP2 dust mask and safety goggles when sanding, and ventilate well. work gloves with nitrile coating protect your hands against filler and paint. Stand on a stable ladder on a level surface and do not overreach to the side; move the ladder one more time instead. Do not drill or sand near sockets and switches and leave cover plates in place: electrical work is for a registered electrician. Read more about putty knives and sanding tools in our blog on putty knives, sanding tools and scrapers.

When do you call in a professional?

• For cracks that keep coming back or get wider.
• If plaster sounds hollow or is loose over a larger area. Read more in our blog on plastering a wall.
• For damp patches, mould or paint flaking because of moisture.
• For walls in older homes where asbestos or lead-based paint may be present.
• If you want a smooth, even finish on a large wall: a painter or plasterer has the routine for that.

Frequently asked questions

How long does filler take to dry?

That depends on the product and the thickness of the layer. Small holes often dry quickly, deep holes take longer. Follow the packaging.

Do I have to repaint the whole wall?

For small spots and the same paint, usually not. If you still see a difference after drying, paint the whole surface from corner to corner.

Can I fill a torn-out plug hole this way too?

Yes, with a few thin layers of filler. If you want to hang something there again later, choose a different spot or a suitable plug.

Read also: How to fix a leaking tap

Getting to work next weekend?

Next weekend we finally hang up what has been leaning against the wall for months: a mirror, shelf or cabinet. You will read how to drill safely, choose the right plug for masonry or plasterboard and avoid pipes and cables. It is an indoor job with some noise and dust, so ideal for a rainy autumn weekend.

Get this ready:

• SDS-plus rotary hammer
• SDS-plus concrete drill bit
• universal expansion plug
• plasterboard plug
• screws for wood and chipboard
• multifunction wall detector
• 60 cm spirit level
• carpenter pencil
• tape measure with auto-lock
• construction vacuum cleaner
• safety goggles
• FFP2 dust mask
• work gloves with nitrile coating
• earplugs

Where can you find everything for this job?

At Saniso, the online store for DIYers and professionals, you will find tools, materials and personal protective equipment for your job.

• Browse our construction tools and our workwear and safety.
• Create a customer account and order easily.
• Working on a bigger project or want to hand over the job? Request a project quote.
• Book a showroom visit, at least 24 hours in advance.
• Not sure which material suits your job? Get in touch with us.

In doubt about the approach? Feel free to call in a professional.

Saniso – Build your home with Saniso.