Walk into any builders’ merchant and you’re looking at a rack of boards that all look pretty much the same. Pink edge, paper face, grey back. But specify the wrong one and you can fail a fire compartmentation test, fall foul of Building Regulations Part E on acoustic performance, or watch a bathroom ceiling bubble and stain within two years. I’ve seen all three happen on otherwise decent jobs, and the cause is almost always the same: someone grabbed whatever was nearest on the pallet without reading the spec.
This guide runs through the main plasterboard types UK tradesmen actually encounter, when each one is required, how to read the key numbers on a manufacturer data sheet, and the errors that cause problems at inspection.
Standard wallboard: what it is and where it stops
Standard plasterboard (sometimes called wallboard or baseboard) is your everyday 9.5mm or 12.5mm gypsum panel. It’s fine for internal partitions and ceilings in dry, habitable rooms where there are no acoustic, fire or moisture demands beyond the basic. Most domestic living rooms, bedrooms, hallways: standard board is perfectly adequate.
The problem is that people treat it as the default everywhere, including places where it simply cannot perform. Standard board has no meaningful resistance to moisture, offers no additional fire protection beyond its basic gypsum core, and does very little for sound reduction on its own. Use it in the wrong location and you’re not just making a quality error; in some cases you’re building something that won’t pass inspection under Approved Document B or Part E of the Building Regulations.
Fire-rated plasterboard: reading the spec correctly
Fireboard (you’ll also hear it called Type F, fire-check or fire-resistant board) has a modified core with glass fibre reinforcement and additives that slow the spread of heat. The key figure on the data sheet is the fire resistance period, measured in minutes: typically 30 or 60 minutes, sometimes 90 or 120 on specialist boards.
What that number actually means matters. A 30-minute fire rating means the board, in the specified assembly, maintains its integrity for 30 minutes under a standard furnace test. That assembly is critical. The board thickness, the stud centres, the screw pattern, the joint treatment and the number of layers all form part of the tested system. Swap one element and the rating is void. I’ve seen lads fit a single layer of 12.5mm fireboard to steel studs at 600mm centres and assume they’ve hit 60 minutes because the board said “60 min” on the label. They hadn’t, because the test that produced that figure used a two-layer system at 400mm centres.
Under Approved Document B, fire compartmentation is required between floors in houses of multiple occupation, between a garage and living space, around stairwells in multi-storey dwellings, and in various commercial settings. Always check the manufacturer’s system certificate, not just the board spec sheet in isolation. Knauf, British Gypsum and Siniat all publish full tested system documents; use them.
Acoustic plasterboard for Part E compliance
Part E of the Building Regulations covers sound insulation in dwellings. It applies to new builds, conversions and certain change-of-use projects. The target figures are expressed as DnTw (airborne sound) and LnTw (impact sound), and missing them means a failed pre-completion sound test.
Acoustic plasterboard (soundboard) is denser than standard board, typically 12.5mm or 15mm with a higher mass per square metre. Mass is the single biggest factor in airborne sound reduction: the heavier the wall, the harder it is for sound energy to move through it. A standard 12.5mm board weighs roughly 8.5 kg/m²; a good acoustic board at the same thickness will be around 11-13 kg/m². That difference adds up across a whole partition.
But board alone won’t get you to the Part E targets in most separating wall or floor assemblies. You need the full system: correct stud type and centres, acoustic mineral wool in the cavity, resilient bar on ceilings, acoustic mastic at perimeters, and the right number of board layers. The commonest failure I’ve seen on sound tests is gaps at junctions, particularly where partitions meet the structural floor or ceiling. Sound travels through air paths as readily as through solid structure, and a 5mm gap around a service penetration can wreck an otherwise solid assembly. Seal everything. Cavity wall construction carries similar risks when thermal and acoustic continuity is broken at junctions.
Moisture-resistant board: bathrooms, kitchens and wet areas
Moisture-resistant plasterboard (MR board, sometimes sold as Aquaboard or similar trade names) has a water-repellent additive in the core and a moisture-resistant facing. It’s the right choice behind tiles in bathrooms, in kitchens behind splash zones, and in utility rooms or any area with persistent humidity.
One point worth being clear on: MR board is not waterproof. It tolerates intermittent moisture and raised humidity without the core degrading, but it is not a tanking membrane. If you’re lining a shower enclosure or wet room floor-to-ceiling area, you still need a full waterproofing system over the board. I covered this in detail in the piece on wet room waterproofing and tanking systems, but the short version is: MR board plus tile adhesive is not a watertight assembly.
The standard thickness for walls is 12.5mm; ceilings in humid rooms are better at 15mm for rigidity. Check the fixing specification too: standard drywall screws will corrode in persistently damp environments, so use zinc-plated or stainless fixings where appropriate. Same logic as specifying external fixings, just applied internally.
Combination boards and specialist products
The market has boards that combine properties: fire and moisture-resistant in one panel, or acoustic and fire combined. These are useful in plant rooms, commercial kitchens, HMO bathrooms and similar spaces. Read the data sheet carefully because the combination rating is sometimes lower than the individual specialist boards would achieve separately. A combined fire/MR board might offer 30-minute resistance where a dedicated fireboard gives 60 minutes.
Thermal plasterboard (dot-and-dab insulated boards with a rigid foam backing) is a separate category again. These are common on internal dry-lining of solid external walls and need to be detailed carefully to avoid cold bridging at perimeters, which is an increasingly common Building Control issue now that energy performance is under greater scrutiny.
How to read a manufacturer data sheet without getting lost
The key fields to check on any data sheet are: thickness and weight per m², fire performance (the test standard used, typically BS EN 520 or BS EN 15283), acoustic data if relevant (surface mass and any published Rw values), edge profile (tapered, square or bevelled, which affects jointing method), and the system certificate reference number. That last one is what Building Control actually want to see if there’s any question over the assembly.
Never rely on the merchant’s description alone. “Fire-resistant” on a shelf label tells you almost nothing about the tested system. Pull the actual data sheet from the manufacturer’s website, check the system document, and make sure what you’re building matches it. Five minutes of checking at the start saves a remedial visit and an argument with the inspector later.
Common errors that cause failed tests
Wrong board in the wrong place is the obvious one, but the subtler errors cause just as many problems. Screw spacing is frequently wrong: most fire-rated systems specify screws at 150mm centres in the field and 200mm at perimeters, but site habit is often 300mm throughout. Joints not staggered between layers, particularly in two-layer fire systems, are another common failure point. Using the wrong joint compound (settling compound instead of a joint compound rated for the system) can affect both fire performance and acoustic performance.
Service penetrations are where compartmentation most often fails in practice. Every cable, pipe or duct that passes through a fire-rated partition needs a tested intumescent collar or a compliant stopping system. Leaving it to the electrician or plumber to sort at the end, without specifying the requirement upfront, is a recipe for gaps. The same discipline that applies to drainage penetrations through floor structures applies here: plan the penetration detail before the board goes up, not after.
Get the spec right from the start, use the tested system, and read the data sheet properly. It’s not complicated. It just requires paying attention to the right information before the boards go on the truck.
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