How to Fit Magply Board: Cutting, Fixing and Safety

Learning how to fit Magply board is mostly about preparation: planning the sheets, using the right fixings and keeping the dust under control. This guide covers cutting, fixing, jointing and finishing as Magply describes them, plus the safety points that matter on site. Always follow the manufacturer's instructions for your project, and the designer's specification if the board is part of a fire-rated system.

How to fit Magply board: before you start

• Read the instructions. Magply's dry lining guidance, Magply's brochure and Magply's data sheet are the sources for fixing details. If the board is part of a tested fire system, build it exactly as the system describes.
• Check the frame. Magply's guidance is that the frame must be structurally sound and the edges of the board must land on the frame. Where the frame is steel, use fixings in line with the frame manufacturer's recommendations.
• Plan your sheets. Each sheet is 2400 × 1200mm (2.88m²). Lay out the joints before you cut so the edges fall on studs.
• Get help lifting. The 9mm sheet weighs 28.5kg and the 18mm sheet 56kg according to Magply's brochure. Carry sheets on their edge with two people.
• Store them properly. Keep sheets flat, dry and off the ground. Our delivery and storage checklist has tips for taking a lorry delivery.

Tools and protective kit

• A carbide-tipped scoring knife or sharp utility knife, and a straight edge
• A masonry hole saw or jigsaw for circular cuts and openings
• A dust mask, safety glasses and gloves
• A HEPA filter vacuum cleaner or a damp cloth for cleaning up
• Screws, nails or adhesive as recommended by Magply for your frame, and a sealant and jointing tape suited to the application

How to cut Magply board

Magply says the board can be cut to size on site by scoring and snapping:

1. Mark the cut line with a pencil and lay the straight edge along it.
2. Score firmly along the line with a carbide-tipped knife. Magply's fire protection board guidance says to cut through the reinforcing mesh.
3. Pull the edge of the board upwards to snap along the score.
4. For circular cuts such as pipes and downlight holes, use a standard masonry hole saw fitted to a drill, or a jigsaw.

Cut outdoors or in a well-ventilated area where you can. Magply says its products do not contain crystalline silica, but it still advises avoiding breathing the dust and always wearing a dust mask. At the end of the job, clean dust off clothes and the work area with a HEPA vacuum or a damp cloth, rather than sweeping it into the air.

How to fix Magply board

Magply's published guidance is to fasten the board with adhesive, nails or screws at roughly 200mm spacing, with fixings 15mm in from the edges and 50mm in from the corners of the sheet. It recommends stainless steel screws for all applications, using countersunk heads on timber and metal studs, and case-hardened stainless or self-tapping screws on metal studs. We have deliberately not given a screw length here, because the right fixing depends on the board thickness, the frame and the specification. Check with Magply's technical line, listed in the brochure, or call us.

A few more points from Magply's guidance:

• Keep joints on the framing, with the vertical joints centred on studs.
• If you need to hang shelves or heavy items, fix only into timber studs or pre-installed noggins.
• Where the wall will be fire-rated, seal the joints with Magply's intumescent sealant in line with the specification, and use the tested layers, thicknesses and fixings only.

Jointing and finishing

Magply says the surface is flat and ready for decoration once primed. It recommends sealing joints with Magply sealant, and an alkali-resistant jointing tape about 50mm wide can be used to strengthen them. Prime the board with a primer that Magply recommends before painting, papering, plastering or tiling. Magply specifically advises against PVA and some other proprietary primers, and says never to use self-adhesive glass tape on the joints. Skimming is possible, but follow Magply's guidance on the primer and the plaster. For tiling, Magply recommends sealing with an approved primer and using a flexible cement-based adhesive.

Common mistakes to avoid

• Fixing at random instead of into the frame
• Using ordinary screws in an application where the manufacturer recommends stainless steel
• Using PVA as a primer or glass tape on joints
• Mixing and matching layers in a tested fire system
• Cutting without a mask, or sweeping dust dry

If you are still deciding which sheet to use, our Magply thickness guide compares the 9mm, 12mm and 18mm options. For fire-rated walls and ceilings in general, read the fire rated insulation and fire-resistant drylining guide.

Frequently asked questions

How do you cut Magply board?

Score along a straight edge with a carbide-tipped knife, cutting through the reinforcing mesh, then snap the sheet over the score. Use a masonry hole saw or jigsaw for circular cuts. Wear a dust mask.

What screws do you use for Magply board?

Magply recommends stainless steel screws for all applications, and countersunk heads on timber and metal studs. The length depends on the board, the frame and the specification, so check with Magply or the system designer.

Do you need a dust mask when cutting Magply?

Yes. Magply advises avoiding breathing the dust and always wearing a dust mask. Clean up with a HEPA vacuum or a damp cloth.

Can you paint or plaster Magply board?

Magply says the board can be painted, papered, tiled or skimmed once it has been primed with an approved primer. It advises against PVA and says never to use self-adhesive glass tape on joints.

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).