Skimming for smooth walls, ready to decorate.

When is skimming the right choice?

Skimming is right when the wall or ceiling underneath is firm, dry and roughly flat, but the surface looks tired. It gives you a fresh, even finish without the cost and mess of re-plastering from scratch.

Typical reasons people ask me to skim a room:

• old plaster covered in filler marks, nail holes and past repairs
• walls left rough after wallpaper has been stripped
• new plasterboard that needs a finish
• a ceiling with fine cracks or old texture that is otherwise sound
• a room being renovated before new flooring and decoration

When isn't skimming enough?

When the problem is underneath. A skim coat is thin, so it follows whatever it sits on, and it cannot hold loose plaster in place.

If I tap a wall and it sounds hollow, the old plaster has lost its bond (known as blown plaster) and needs cutting out and making good first. Very uneven walls may need a backing coat or plasterboarding to bring them straight. Damp walls need the cause dealing with, and older solid walls may be better suited to lime. Where there are cracks or damaged areas, I start with plaster repairs and skim once the background is right.

How do I prepare a wall before skimming?

Preparation is most of the job, even though you will never see it once the finish goes on. It is also where quotes differ most.

1. Protect floors, furniture and fittings, and remove or loosen sockets and switch plates safely.
2. Tap-test the walls and cut out any blown or loose areas.
3. Fill holes and deep defects so the skim is even in thickness.
4. Fit new beads on damaged or out-of-line corners.
5. Tape cracks and board joints with scrim so they do not reappear.
6. Prime or bond the surface to control suction, so the plaster grips and does not dry too fast.

Then the skim goes on in two thin coats and is trowelled up to a smooth, tight finish, with attention to edges, corners and the lines around windows and doors.

Can you skim over Artex or textured ceilings?

Often yes, but older Artex should be tested for asbestos before any preparation that could disturb it. Heavy patterns may need two coats or overboarding instead. I explain the options on my plastering over Artex page.

How long before you can decorate a skimmed wall?

Usually several days to a week or more, depending on the time of year, heating and ventilation. The plaster is dry when it has turned an even, pale colour with no darker patches.

Keep the room gently heated and ventilated, but do not blast heaters at fresh plaster, as drying too fast can cause fine cracking. The first coat of paint should be a mist coat: watered-down, water-based emulsion that soaks in and seals the surface. Vinyl, silk and oil-based paints sit on top of new plaster and tend to peel. I give you this advice in writing at handover.

Can you skim walls in an older house?

Yes, but it needs more thought. Many houses built before about 1920 have lime plaster on solid brick, and a modern gypsum skim does not always bond well to it or suit the way the wall handles moisture.

On a sound, dry internal wall a gypsum skim with the right bonding primer can be fine. On an outside wall that shows signs of damp, or where the old lime is soft and dusty, a lime finish is usually the safer choice. Many 1930s semis in Sutton Coldfield and Great Barr have a mix of original plaster and later gypsum patches, so I test and look before recommending anything.

What affects the cost of skimming?

The size of the room is only part of it. The price depends mostly on how much preparation the surface needs.

• how many blown areas, cracks and holes need repairing first
• whether ceilings are included, and their height
• new beads, scrim and priming
• how much furniture needs protecting and whether wallpaper needs stripping

I price after a free visit and write the preparation into the quote, so you can compare it properly with others.

What makes my skimming different?

Not speed, and not being the cheapest. Most people can spot a poor finish, but few can see the preparation that decides whether a good finish lasts, so I show you it while it is still visible. I check the background, explain what needs doing and why, and prepare the wall properly, so the finish stays right after you decorate. Floors are protected, we clean every day, and I call about four weeks later to check everything has dried and settled. Skimming is part of my wider plastering service across Sutton Coldfield, Walsall and nearby.