plaster types UK

UK plasters fall into three groups: undercoat plasters (bonding, browning, hardwall and tough coat) that level the wall, finishing plasters (multi-finish and board finish) that give the smooth top coat, and specialist plasters (one coat, lime and Venetian) for particular jobs. Pick your undercoat by how much suction the background has, then skim it with a finishing plaster. Key facts Undercoat plasters go on 8-15mm thick; finishing plasters go on at 2-3mm Bonding suits low-suction backgrounds (concrete, plasterboard); browning suits high-suction brick Multi-finish is the standard top coat on most domestic jobs A 25kg bag of undercoat covers roughly 2.4-3.4m²; a bag of finish covers 9-10m² Undercoat bags cost £8-£15 and finishing plaster £9-£13 (July 2026) Understanding Plaster Types: Why It Matters Walk into any builders’ merchant in Kent, whether it’s Travis Perkins, Wickes, or your local independent, and you’ll face bags of pink, grey, and white plaster with names like Thistle, Carlite, and Dri-Coat. For anyone new to plastering, it’s bewildering. But here’s the truth: using the wrong plaster type is one of the most common mistakes in plastering, and it accounts for a large share of the cracking, delamination, and adhesion failures we see on renovation jobs across Kent and the Southeast. Modern gypsum plasters manufactured by British Gypsum are engineered products designed for specific substrates and applications. Understanding the differences isn’t just technical nitpicking, it’s what gets you a durable, professional finish that lasts decades. What are the main types of plaster? Every plaster on the merchant’s shelf sits in one of three categories: Undercoat plasters (basecoats): Applied first to level uneven surfaces, typically 8-15mm thick, designed to key to the substrate Finishing plasters (skim coats): Applied over undercoats or directly to plasterboard, typically 2-3mm thick, creating the smooth surface you decorate Specialist plasters: One coat, lime, Venetian, renovating and other formulations for specific jobs Here’s the full range at a glance: Plaster type Category Use case Typical thickness Bonding Undercoat Low-suction backgrounds: concrete, plasterboard, painted surfaces 8-12mm (25mm max) Browning Undercoat High-suction backgrounds: common brick, lightweight blocks 8-12mm per coat Hardwall Undercoat Most masonry backgrounds, fast drying 11mm Tough Coat Undercoat Hallways and high-traffic areas needing impact resistance 11mm Multi-Finish Finishing Skim coat over undercoats and most prepared backgrounds 2-3mm Board Finish Finishing Skim coat direct to new plasterboard 2-3mm One Coat Specialist Patch repairs and small jobs, base and finish in one 5-50mm Lime Specialist Period and heritage properties needing breathable walls 6-12mm per coat Venetian Specialist Decorative polished feature walls 1-2mm in thin layers Most plastering jobs use an undercoat and a finish in a two-coat system, unless you’re skimming directly over plasterboard, where you’d use only a finishing plaster. This distinction is covered in detail in our complete guide to plastering. Is undercoat plaster the same as bonding? No. Bonding is one type of undercoat plaster, not another name for it. Undercoat plaster is the category: any plaster applied first to level a wall before skimming. Bonding, browning, hardwall and tough coat are all undercoat plasters, and you choose between them based on how much suction the background has. The confusion comes from merchants and plasterers using “undercoat” and “bonding” loosely. When a plasterer says they’re “putting bonding on”, they mean Thistle Bond-It specifically, which is made for low-suction backgrounds like concrete and plasterboard. Put bonding on thirsty common brick and it sets before it can grip properly. That wall needs browning or hardwall instead. So don’t ask the merchant for “undercoat plaster”. Tell them what the wall is made of and buy the type that matches it. Undercoat Plasters: Bonding, Browning, Hardwall and Tough Coat Bonding Plaster (Thistle Bond-It) Bonding plaster is the workhorse of modern plastering. If you only learn one undercoat, make it this one. It’s a gypsum-based undercoat formulated for low-suction or non-porous backgrounds. We cover it in depth in our bonding plaster guide. Best used on: Concrete blocks and dense concrete Plasterboard (when building up thickness) Painted surfaces (after proper preparation) Engineering bricks Expanded metal lath (EML) Surfaces treated with PVA or bonding agents The key characteristic of bonding plaster is its excellent adhesion to smooth, low-suction surfaces where other plasters would simply slide off or fail to grip. It contains additives that improve its “stick” to difficult substrates. Pro Tip: Bonding can be applied up to 25mm thick in a single coat if necessary, though 8-12mm is standard. If you need more depth, build it up in multiple layers, letting each cure before applying the next. Never exceed 50mm total depth without mechanical fixings or EML reinforcement. Working characteristics: Setting time: 1.5-2 hours Coverage: One 25kg bag covers approximately 2.4-2.75m² at 12mm thickness Drying time: 5-7 days before applying finish coat (depending on ventilation and temperature) Colour: Pink/grey when wet, lighter when dry As of 2026, expect to pay £8-£12 per 25kg bag from major suppliers, with Thistle Bond-It being the industry standard. Learn more about preparing surfaces in our guide to the first coat of plaster application. Browning Plaster (Thistle Browning) Browning plaster is the traditional undercoat for high-suction backgrounds: porous materials that suck moisture from plaster rapidly. Our separate browning plaster guide covers mixing and application in detail. Best used on: Common bricks and clay bricks Medium-density concrete blocks Lightweight aggregate blocks Older lath and plaster (after preparation) The difference between Browning and Bonding isn’t always obvious to DIYers, but it’s critical. Browning contains retarders that slow down the set, allowing the plaster to cure properly even when the substrate is pulling moisture out quickly. Use Bonding on high-suction brickwork, and you’ll find it sets too fast and doesn’t develop proper strength. Working characteristics: Setting time: 1.5-2 hours Maximum thickness: 12mm per coat Drying time: 7-14 days before topcoat (longer than Bonding due to substrate absorption) Colour: Pink when wet Hardwall Plaster (Thistle Hardwall) Hardwall is a more recent innovation: a faster-drying, higher-impact-resistance undercoat suitable for both medium and high-suction backgrounds. It’s become increasingly popular on new-build sites. See our hardwall plaster guide for