Plasterboard Types Explained: Standard, Fire, Moisture & More
The most effective plasterboard for your project depends entirely on the specific performance requirements – such as fire rating, acoustic insulation, or thermal efficiency – of the room in question.
Key Takeaways:
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Standard 12.5mm Board: The industry standard for general internal walls and ceilings.
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Moisture-Resistant: Mandatory for “wet zones” like bathrooms and kitchens to prevent mould and structural softening.
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Fire-Rated: Essential for garages, hallways, and structural partitions to meet Part B of the Building Regulations.
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Acoustic/Sound Board: Higher density core designed to reduce decibel transfer between rooms.
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Insulated Boards: A 2-in-1 solution for improving thermal U-values on external-facing masonry walls.
What is Plasterboard and Why Does Type Matter?
Plasterboard, often referred to as drywall or gypsum board, is a construction material consisting of a core of calcium sulfate dihydrate (gypsum) sandwiched between two layers of heavy-duty paper or felt. Understanding what is plasterboard made of is essential for professionals, as the additives within the gypsum core determine the board’s performance under stress, heat, or humidity.
In the UK, selecting the correct board is not just a matter of preference but of compliance. Each variant is engineered to solve a specific architectural challenge, from preventing “wicking” in damp environments to slowing the spread of flame in multi-storey dwellings.
Comparison of Plasterboard Types & Specifications
Pro Insight: The “Tapered vs Square” Rule
A common mistake in procurement is overlooking the edge profile. Tapered edge plasterboard features a slight indentation at the long edges, designed for “jointing and taping” to achieve a seamless finish without skimming the entire wall. Conversely, square edge plasterboard is typically preferred for textured finishes or when a professional plasterer is applying a full skim coat of multi-finish. For a deeper dive into which profile suits your finish, see our guide on tapered or square edge plasterboard.
Which Board Do You Need?
Choosing the right material requires assessing the environmental risks of the room.
1. General Living Areas
For standard bedrooms and lounges, standard plasterboard is the recognised standard. In most residential timber-frame or metal-stud partitions, 12.5mm is used to ensure structural rigidity and a 30-minute fire rating when installed correctly.
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Requirement: Use 12.5mm plasterboard for standard stud spacing (400mm-600mm centres).
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Ceilings: Thinner 9.5mm plasterboard is sometimes utilised for over-boarding existing ceilings where weight is a primary concern.
2. High-Moisture Environments
Standard gypsum is hygroscopic, meaning it absorbs water, leading to “blown” plaster and mould. In en-suites or laundry rooms, moisture-resistant plasterboard contains silicone additives in the core to repel water. You can learn more about the versatility of plasterboard for bathrooms to ensure long-term durability.
3. Fire Safety & Regulations
To satisfy UK Building Regs (Part B), certain areas require enhanced protection. Fire-rated plasterboard contains glass fibres and other additives to maintain structural integrity during a fire. For high-performance commercial specifications, 15mm plasterboard in fire-grade is often the industry standard to achieve a 60-minute fire rating.
4. Acoustic Insulation
If the goal is to reduce airborne noise between a home office and a living room, soundproof plasterboard is the high-density solution. These boards have a much higher mass per square metre, which is the physics-based requirement for dampening sound vibrations.
5. Thermal Efficiency & Condensation
On cold external walls, insulated plasterboard (bonded with PIR or EPS foam) helps prevent heat loss. If you are concerned about interstitial condensation within the wall cavity, foil-backed plasterboard acts as a high-performance vapour control layer.
Practical Execution: Installation Tips
Once you have selected the correct performance board, the quality of the finish depends on the installation technique.
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Measuring: Ensure you account for a 3-5mm gap at the floor to prevent moisture wicking.
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Cutting: Use a sharp utility knife to score the ivory face before snapping the board. For complex shapes, follow our how to cut plasterboard step-by-step guide.
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Fixing: When mounting to timber, use “black” phosphate drywall screws. For masonry, the “dot and dab” method using bonding compound is standard. See our detailed breakdown on how to fix plasterboard for specific screw spacings.
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Finishing: Even the best installation can suffer from accidental damage during a build. If you encounter minor dings or pipe-entry errors, consult our guide on how to fill holes in plasterboard for a professional repair.
FAQs
How do I know which side of the plasterboard to plaster? Typically, you plaster the “ivory” or coloured side. The grey/dull side is the back. For performance boards (like fire or moisture), the coloured face must face into the room so the identification remains visible for building inspectors before skimming.
Can I use fire-rated board in a bathroom? While fire boards are dense, they are not moisture-treated. In a high-humidity environment, the gypsum core will eventually fail. If you need both fire and moisture protection, you must look for “multiboard” specifications that combine both properties.
Is 15mm board always better than 12.5mm? Not necessarily. While 15mm offers better fire and acoustic performance, it is significantly heavier and may require additional structural support or two-person handling. Only use 15mm where specific performance targets or building regulations dictate.
Project-First Recommendation: For most residential renovation projects, the best starting point is 12.5mm Tapered Edge Plasterboard. View available sizes and specifications here.
If you are dealing with high-humidity zones like wet rooms or kitchens, Moisture-Resistant Board is the industry-standard choice.
