Which Plasterboard Do I Need? Standard, Moisture, Fire & Acoustic Boards

Summary

Plasterboard selection is one of the most common sources of specification errors on site. The standard grey-faced board is not appropriate for all situations, and using the wrong product leads to swelling, delamination, fire compliance failures, or unnecessary cost. Most electricians, plumbers, and joiners encounter plasterboard when chasing and making good — understanding the different types helps you specify correctly when making good after pipe or cable runs.

The UK market is dominated by British Gypsum (Gyproc brand) and Knauf, with Lafarge and USG also active. The board types and their applications are consistent across brands. Board is typically sold in 1200mm × 2400mm (or 2700mm) sheets, in thicknesses from 9.5mm to 19mm.

This guide covers all common plasterboard types, their physical properties, appropriate applications, and relevant fire performance classifications.

Key Facts

• Standard board (WallBoard) — 9.5mm or 12.5mm; grey face / ivory back; suitable for all dry internal walls and ceilings
• Moisture-resistant board (MR board) — green face; contains hydrophobic additives; for kitchens, bathrooms, utility rooms; NOT fully waterproof — still requires waterproofing in wet zone applications (see waterproofing)
• Fire-resistant board (Fireline) — pink or red face; glass fibre additives reduce calcination rate; used in fire-rated wall and ceiling systems; typically 12.5mm or 15mm
• High-density fire board — 15mm or 19mm Fireline; for FR60 and FR90 rated constructions; heavier and harder to cut
• Acoustic board — high-density gypsum; heavier than standard; mass improves sound reduction; used on party walls and separating floors
• Thermal board / PIR composite — plasterboard bonded to a rigid insulation backing (PIR, EPS, or mineral wool); used for internal wall insulation; total thickness varies
• Vapour check board — foil-backed; acts as vapour barrier; used in specific insulated wall and roof systems
• Board thickness for walls — standard 12.5mm for walls; 9.5mm for lightweight ceiling lining
• Board thickness for ceilings — 12.5mm standard; 15mm where span exceeds 450mm between joists/framing
• Edge profiles — tapered edge (TE): recessed edges for jointing; square edge (SE): no recess; bevelled edge (BE): chamfered for specific systems
• Screws spacing — perimeter: 150mm; field: 300mm for ceilings; 150mm for walls; minimum 10mm from edge

Quick Reference Table

Detailed Guidance

Standard Board — When It's Right

Gyproc WallBoard (British Gypsum) or Knauf Drywall is the correct product for:

• All dry living rooms, bedrooms, hallways, and stairwells
• Loft conversions and attic rooms (non-fire-rated, dry)
• Making good after pipe and cable chasing in dry rooms
• First fix drylining of steel or timber frame walls

For ceilings with joists at 400-450mm centres, 12.5mm board is standard. For joists at wider spacing (up to 600mm), use 15mm board.

Moisture-Resistant Board — Kitchens and Bathrooms

Green-faced MR board is the minimum requirement behind tiling in kitchens and bathrooms. Standard board wicks moisture, the gypsum core softens, and tile adhesive fails — sometimes within months on a poorly ventilated bathroom.

However, MR board alone is not waterproof enough for wet zone applications (shower enclosures, areas directly splashed with water). In these zones, a full waterproofing membrane (tanking system) is required over the MR board before tiling (see waterproofing). MR board provides basic moisture resistance for steam and condensation; it is not a substitute for a properly tanked wet area.

Manufacturers' recommendations:

• British Gypsum Gyproc MR: suitable for kitchens and bathrooms; requires tanking in direct splash zones
• Knauf Aquapanel: cement board system for shower enclosures; fully waterproof without additional tanking

Fire-Resistant Board — Building Regulations Requirements

Building Regulations Approved Document B (Fire Safety) specifies fire performance requirements for:

Fireline board is classified to BS EN 520 Type F and BS EN 13238. Do not use standard board in fire-rated constructions — this is a Building Regulations compliance failure.

Never cut Fireline on site with an angle grinder — the glass fibre creates a health hazard (respirable fibres). Score and snap, or use a dedicated plasterboard saw.

Acoustic Board — Party Walls

Acoustic board works on the principle of mass — heavier materials transmit less sound. Gyproc SoundBloc (15mm) or Knauf Acoustic board offers increased sound reduction compared to standard 12.5mm board.

For party walls in new builds and conversions, the Building Regulations Approved Document E (Resistance to Sound) sets minimum performance standards. Standard plasterboard alone rarely meets these requirements — a complete tested system (specified by the manufacturer) is needed.

Typical party wall system: 2 × 15mm SoundBloc on independent steel stud frame, mineral wool quilt between, resilient bar on one side. This is a manufacturers' system (British Gypsum Gyproc party wall solutions) and must be installed as specified.

For minor sound improvement (not Building Regulations compliance), adding 15mm acoustic board to an existing wall provides a meaningful improvement without a complete rebuild.

Thermal / Composite Board — Internal Wall Insulation

Insulated plasterboard (thermal board) consists of standard plasterboard bonded to an insulation layer — typically rigid PIR foam (e.g. Celotex, Kingspan), EPS beads, or mineral wool. Total thickness ranges from 37.5mm (12.5mm board + 25mm PIR) to 100mm+.

Thermal board is commonly used for:

• Solid wall insulation in older properties
• Cold bridging treatment on external walls
• Improving thermal performance under Building Regulations Part L

Fix with dabs of Gyproc Easi-Fill or plasterboard adhesive plus mechanical fixings. These boards are heavy — a 2400 × 1200 × 62.5mm sheet weighs approximately 25kg. Two-person lifting is required. See dot and dab for the standard fixing method.

Board Dimensions and Sheet Sizes

Standard sheet size is 1200mm × 2400mm (or 2700mm). Check ceiling heights before ordering — a 2400mm sheet standing vertical in a 2400mm room has zero spare for trimming.

Frequently Asked Questions

Can I use standard plasterboard in a bathroom?

Not recommended. In a bathroom, use moisture-resistant (green) board as a minimum. In shower enclosures and direct splash zones, either use a cement board (Knauf Aquapanel, Jackoboard) or install a tanking membrane over the MR board before tiling.

Does the fire-rated room need Fireline on all surfaces?

Consult Approved Document B for the specific scenario. For a domestic garage-to-house partition, typically only the ceiling and the dividing wall need to be FR-rated — not all four walls of the garage. For HMO fire compartmentation, consult with Building Control for the specific requirements.

Can I mix Gyproc and Knauf products in the same system?

Generally yes for basic applications — both are gypsum boards to BS EN 520 and standard jointing compounds are compatible across brands. For fire-rated or acoustic systems, use a single manufacturer's tested system — mixing products from different manufacturers invalidates the tested performance and may fail Building Control.

What's the difference between tapered edge and square edge?

Tapered edge (TE) boards have a slight recess along the long edges, designed to receive jointing tape and compound and produce a flush, invisible joint. Square edge (SE) boards are for areas that will be plastered over — the joint is filled with plaster, not compound. Use tapered edge for dry-lining finished with jointing compound; square edge for boards that will be skimmed.

Regulations & Standards

• BS EN 520 — gypsum plasterboards; definitions, requirements and test methods

• BS EN 13950 — gypsum board thermal/acoustic composite panels

• Building Regulations Approved Document B — fire safety; specifies performance requirements for fire-rated walls and ceilings

• Building Regulations Approved Document E — resistance to sound; covers party walls and separating floors in new builds and conversions

• Building Regulations Approved Document L — conservation of fuel and power; relevant to insulated thermal board specifications

• British Gypsum White Book — the definitive specification guide for all Gyproc and Thistle products

• Knauf Technical Documentation — full product range data sheets

• Building Regulations Approved Document B — fire safety requirements

• Building Regulations Approved Document E — sound insulation requirements

• skim coat — skimming over plasterboard once installed

• dot and dab — dot and dab fixing for plasterboard to masonry

• waterproofing — waterproofing wet areas before tiling

• bathroom zones — bathroom zone requirements relevant to board selection