Skimming Over Artex and Painted Walls: Prep and Bonding

Summary

Skimming over an existing textured or painted surface is one of the most common plastering jobs in UK homes — far more common than re-plastering from bare brick. Done right, it turns a dated Artex ceiling or a glossy painted wall into a flat, paint-ready finish in a day. Done wrong, it either disturbs asbestos or de-bonds and falls off in sheets weeks later. The two failure modes — asbestos exposure and poor adhesion — are what this article is about.

The safety point comes first because it is not optional. Textured coatings ("Artex" is a brand name that became generic) applied up to around the year 2000 commonly contained chrysotile asbestos, typically 2–5%. You cannot tell by looking. Sanding, scraping dry, or abrading such a coating releases asbestos fibres. Overskimming an undisturbed textured coating is recognised as a low-risk way to deal with it precisely because it encapsulates rather than removes — but anything that involves sanding the Artex first crosses into work that may be notifiable / licensed under CAR 2012. If in any doubt, get a bulk sample analysed by a UKAS-accredited lab before you touch it.

The adhesion point is the craft. New plaster needs suction control and a mechanical or chemical key. Bare or porous backgrounds suck water out of the plaster too fast; smooth, sealed or painted surfaces give nothing for it to grip. The fix in both cases is the right primer/bonding agent for the background, applied correctly, plus knocking back any high peaks on heavy Artex so the skim isn't too thick in the troughs.

Key Facts

• ASBESTOS — pre-2000 Artex — textured coatings applied before ~2000 may contain chrysotile asbestos (typically 2–5%). You cannot identify it by sight. Treat as asbestos-containing until proven otherwise.
• NEVER dry-sand, scrape or abrade Artex — this releases fibres. Dry sanding textured coatings is the trigger that pushes the work toward licensed asbestos work under CAR 2012.
• Overskimming is the low-risk option — encapsulating an undisturbed textured coating by skimming over it is recognised (HSE / asbestos essentials) as a low-risk way to deal with it, avoiding removal.
• Sampling — a small bulk sample analysed by a UKAS-accredited laboratory confirms whether asbestos is present before any disturbance.
• CAR 2012 — Control of Asbestos Regulations 2012 governs all work that may disturb asbestos; some textured-coating work is non-licensed (NNLW) but still notifiable, some is licensed.
• Knock back high peaks (if needed) — heavy "stippled" or "swirl" Artex may need peaks taking down. If the coating may contain asbestos, this must be done wet (controlled wet-scraping) under proper controls, not dry-sanded.
• Bonding agent for porous/Artex — diluted PVA (typically two coats, skim into the tacky second coat) or a proprietary acrylic bonding primer to control suction and aid grip.
• Bonding primer for painted walls — a "blue grit" type bonding primer (aggregate-filled acrylic) gives a mechanical key over smooth/sealed surfaces where PVA alone is unreliable on gloss.
• Score glossy/sealed paint — abrade and score sound paint to provide a key; remove any flaking or unsound paint first (paint is only as good as its own adhesion).
• Finish plaster — multi-finish gypsum plaster, applied as a two-coat skim (~2mm + 2mm, ~3–5mm total), trowelled up through its set.
• Suction test — splash water on the background; if it vanishes instantly the suction is high and needs sealing/wetting; if it beads/runs the surface is sealed and needs keying.
• Don't skim over unsound paint or distemper — old chalky distemper and flaking paint must come off; plaster bonds to the failing layer, not the wall.
• Part of "decorating prep" — but the asbestos duty is statutory, not optional good practice.

Quick Reference Table

Detailed Guidance

Asbestos: the decision before any tool touches the surface

Is the textured coating (Artex) likely pre-2000?
        │
   ┌────┴────┐
  YES        NO / unknown ──► still treat as suspect if age unknown
   │
 Do you need to disturb it (sand/scrape/peak-knock)?
   │
 ┌─┴───────────────┐
 NO                YES
 │                  │
 Overskim only      Sample via UKAS lab FIRST
 = low-risk         │
 encapsulation   ┌──┴──────────────┐
                Asbestos present   None
                │                  │
            CAR 2012 controls:   Knock back / sand
            wet methods, RPE,    as normal, then skim
            possibly notifiable/
            licensed work

The safe default for a tradesperson is to overskim without disturbing the coating. Encapsulation by skimming is specifically recognised as low-risk because it locks the fibres in rather than releasing them. The moment the job needs the Artex sanded flat, you are in different territory: sample it, and if asbestos is confirmed, work to CAR 2012 — wet methods, FFP3 RPE, controlled waste, and the appropriate licensed/notifiable status for the task. Never dry-sand a textured coating of unknown age.

Skimming over Artex (assuming it's safe to proceed)

1. Confirm asbestos status as above. Do not skip this for pre-2000 coatings.
2. Knock back high peaks only if necessary. A standard 2-coat skim copes with moderate texture. For heavy swirls, peaks may need taking down — and if there is any asbestos doubt, that must be wet-controlled, not dry.
3. Wash off grease and dust (kitchens/ceilings especially) and let dry.
4. Control suction with PVA: dilute per the maker's ratio, apply two coats, and lay the first skim coat into the tacky second PVA coat — never onto wet, glossy PVA, and never let it fully dry hard before plastering.
5. Two-coat skim: first coat to fill and flatten the texture, second coat to finish; trowel up through the set for a flat, paint-ready surface.

Skimming over painted walls

Paint is the enemy of adhesion because it's smooth and sealed, and because the plaster can only ever be as well-stuck as the paint underneath it.

• Test the paint: scrape and tape-test. If it lifts, it must come off — skim will take the paint with it when it fails.
• Remove unsound paint and all distemper. Old soft distemper is a classic skim-failure cause; it must be removed and the surface stabilised.
• Key sound paint: abrade and score thoroughly. On gloss/eggshell, mechanical scoring plus a "blue grit"-type bonding primer (acrylic with a sand aggregate) gives the key PVA alone can't on a slick surface.
• Prime and skim: once the bonding primer is touch-dry per its data sheet, apply the two-coat skim.

Why bonding fails — and how to avoid it

• PVA over-applied or fully dried before plastering → glassy film, no key. Skim into the tacky coat.
• High suction not controlled → plaster flash-sets, cracks, and de-bonds. Wet down or seal porous backgrounds.
• Skimming over unsound paint/distemper → fails at the weak layer. Strip it.
• Smooth gloss with no key → nothing to grip. Score and use an aggregate bonding primer.
• Skim too thick in Artex troughs → shrinkage cracks. Knock back peaks and build in two coats.

Frequently Asked Questions

Can I just skim over Artex without testing it for asbestos?

You can overskim an undisturbed textured coating without removing it, and that encapsulation is treated as low-risk — but you must not sand or scrape it in the process. The safe practice for any pre-2000 (or unknown-age) coating is to assume asbestos may be present, avoid all dry abrasion, and have a sample analysed by a UKAS lab before doing anything that would disturb it. Never dry-sand Artex.

Will plaster stick to a painted wall?

Only if the paint is sound and given a key. Plaster will not bond to smooth, sealed gloss or to flaking/distempered paint. Remove anything unsound, score and abrade the sound paint, and use a bonding primer — a "blue grit"-type aggregate primer for gloss, PVA or bonding primer for matt emulsion — before skimming.

Should I use PVA or a bonding primer?

PVA works well for controlling suction on porous or matt-painted backgrounds — apply two coats and skim into the tacky second coat. For smooth, sealed or glossy surfaces where PVA can't grip, use an aggregate-filled acrylic bonding primer ("blue grit" type) that leaves a physical key. Many plasterers use the bonding primer as the default over paint because it's more forgiving.

How thick can a skim coat be over Artex?

A finishing skim is typically two coats totalling about 3–5mm. It is not a render — it can't flatten very heavy texture on its own. Heavy Artex needs the peaks knocking back first (wet-controlled if asbestos is possible) so the skim sits at a consistent, thin depth and doesn't shrink-crack.

Is overskimming Artex notifiable under CAR 2012?

Overskimming that simply encapsulates an undisturbed coating is regarded as low-risk and is not the same as removal. But if the work disturbs the coating — sanding, scraping, drilling, peak removal — it may become non-licensed notifiable or even licensed work depending on the method and fibre release. Sample first and follow the HSE asbestos-essentials task sheets for textured coatings.

Regulations & Standards

• Control of Asbestos Regulations 2012 (CAR 2012) — duties for work that may disturb asbestos, including textured coatings; licensed vs non-licensed/notifiable work; Schedule 3.

• HSE Asbestos Essentials / L143 ACOP ("Managing and working with asbestos") — task sheets and approved code of practice covering textured coatings and overskimming.

• BS 8000-10 — Workmanship on construction sites: plastering and rendering (good-practice reference).

• Building Regulations Approved Document E — where plastering affects sound insulation of separating walls/floors (relevant in flats).

• HSE — Asbestos: Textured coatings (asbestos essentials) — task sheets, overskimming as low-risk, what triggers licensed work

• HSE — L143 Managing and working with asbestos (ACOP) — approved code of practice under CAR 2012

• GOV.UK — Approved Document E: Resistance to the passage of sound — where plastering affects sound insulation

• British Gypsum — technical guidance on skim/multi-finish plasters — product application and bonding guidance

• skim coat — two-coat skim method, mixing ratios, timing and trowelling up

• asbestos in textured coatings — chrysotile content, overskimming, wet-scraping, sampling and CAR 2012 licensed-work triggers

• artex asbestos — pre-1985/2000 Artex asbestos risk and the skim-over option from the decorating side

• asbestos — identification by building age, CAR 2012 duties and what to do if asbestos is found