What Is Magply Board and What Is It Used For?
Magply board is a magnesium-based building board sold in large 2400 × 1200mm sheets, and it is best known as a fire rated board. If you have seen it called MgO board, MOS board or "A1 fire board", you are looking at the same family of product. This guide explains what Magply board is, where it is used, what the sizes and thicknesses mean, and what to check before you buy.
What is Magply board?
Magply is the brand name of IPP Limited. Magply's brochure describes it as a magnesium oxysulfate board (MOS board) and says it is made with a very low chloride content. The brochure lists it as Euroclass A1 (non-combustible) to EN 13501-1 and Class 0 for surface spread of flame. In plain terms, it is a rigid mineral sheet rather than a paper-faced gypsum board like plasterboard.
We list three sizes, all 2400 × 1200mm (2.88m² a sheet): the 9mm board, the 12mm board and the 18mm board. You can see all of them in our Magply collection.
| Thickness | Price per sheet (ex VAT) | Price per m² (ex VAT) | Weight per sheet (Magply brochure) |
|---|---|---|---|
| 9mm | £37.50 | £13.02 | 28.5kg |
| 12mm | £39.99 | £13.89 | Call us to confirm |
| 18mm | £66.24 | £23.00 | 56kg |
The weight of the 12mm sheet is quoted differently in different Magply documents, so we would rather confirm the figure with you than print one here. Either way, plan on a two-person lift for every sheet.
What is Magply board used for?
Magply's own literature describes it as a fire mitigation sheathing board for timber frame, steel frame, rainscreen cladding, SIP panels, spandrel panels and modular build. It also lists render systems and pattressing, and promotes the board for high-performance dry lining. Magply says the benefits include non-combustibility, moisture protection, mould resistance and strength.
Our product listings describe the Magply sheets we sell as a specialist board for internal construction, so the most common uses for our customers are internal ones:
- Fire-rated wall linings and partitions. Magply publishes fire test results for particular build-ups, such as timber frame, steel frame partitions and spandrel panels. Those results belong to the full tested construction, not to the board on its own.
- Sheathing and framing systems. Part of timber and steel frame construction, where the board is fixed to the frame as part of a designed system.
- Dry lining where a mineral board is wanted. Magply's dry lining guidance covers dry lining in 1200 × 2400mm sheets.
For external uses such as render or rainscreen cladding, the whole system matters, including the fixings and the other materials. Magply's brochure itself points to using materials of limited combustibility throughout a cladding system. Treat the board as one part of a specification from your designer, and check the position with Building Control.
What does A1 mean for fire protection?
Euroclass A1 describes reaction to fire, which is how a material behaves as a fuel. It does not tell you how many minutes a wall or ceiling will hold back a fire. That is fire resistance, and it is tested on a whole construction: the frame, the insulation, the layers of board and how they are fixed. Our fire rated insulation and fire-resistant drylining guide explains the difference in more detail. If your project needs a fire-resistance period, ask your designer for a tested system and build it exactly as specified.
How is Magply different from plasterboard?
Plasterboard has a gypsum core and paper faces. Magply is a mineral board with a magnesium-based core, so it is denser and heavier, and it costs more per square metre. Plasterboard is still the sensible choice for most dry, heated rooms with no special fire demand. We compare them in detail in Magply vs plasterboard vs cement board.
Is Magply board waterproof?
Magply says the board offers moisture protection and is insoluble in water. That is not the same as being waterproof. Where a wall will be wet, such as inside a shower, you need a proper waterproofing system designed for the job, and Magply makes separate tile backer products for that.
Next steps
If you are ready to plan, read how to fit Magply board for cutting, fixing and dust safety, and which Magply thickness you need to pick between 9, 12 and 18mm. For the background on how we describe fire ratings across the range, see our earlier Magply fire safety article.
Frequently asked questions
Is Magply the same as MgO board?
Magply is a magnesium-based board. Magply describes its own formulation as magnesium oxysulfate, which is why you will see it called MOS board as well as MgO board. Boards from different makers are not identical, so always check the datasheet for the product you are buying.
Is Magply board fireproof?
Magply is classed as Euroclass A1, non-combustible, in its brochure. "Fireproof" is not a technical term, and how long a wall or ceiling resists fire depends on the tested build-up it is part of.
What size are the Magply boards you sell?
All three are 2400 × 1200mm, which is 2.88m² a sheet, in 9mm, 12mm and 18mm thicknesses.
Can I use Magply board outside?
Magply promotes the board for render and rainscreen systems, but our listings describe the sheets we sell as for internal construction. If you are planning an external use, ask your designer to confirm the system and the fixings, and contact us before you order.
Ordering and delivery
You can see all three sizes together in our Magply collection, or browse the wider range of building boards. Prices on our website are shown excluding VAT, and VAT is added at checkout. As stated on each Magply product page, we deliver free to addresses in England on orders of £400 + VAT or more. We cannot deliver to Wales, Scotland, Northern Ireland or the islands. Sheets arrive by Moffett lorry with a forklift offload, so someone must be there to receive them. We do not offer next-day delivery, so call us before you order if you have a date to hit. Our shipping policy has the full details. If you would like a hand choosing a board, call us on 03330 908479 or email sales@insulationwarehousedirect.co.uk.
This guide is general information, not a specification. Fire performance, fixings and suitability depend on the whole build-up and the project, so check them with your designer or Building Control and follow the manufacturer's instructions. Prices are correct at the time of writing (28 October 2026).