The fixing needs to pass through the full thickness of the insulation board and embed into the structural substrate behind it. As a general rule, choose a fixing that is 40-60mm longer than the board thickness. For example, a 100mm PIR board would typically require a fixing of at least 140-160mm to get adequate grip in the masonry. Always check the substrate type too, as softer blocks may need longer embedment than dense concrete or brick.
Insulation Board Fixings for Walls, Floors and Roofs
Getting insulation boards to stay put matters as much as choosing the right board in the first place. MacBlair stocks a focused range of insulation fixings, including metal round fixings, hammer-in anchors and metal insulation discs, sized to suit rigid PIR and mineral wool boards on walls, soffits and other solid substrates. These products are galvanised or manufactured from fire-rated materials, with several conforming to EN 13501-1 for fire performance.
The fixings in this range cover a variety of applications:
- Metal round insulation fixings: hammer-in anchors with a disc head that beds into the render coat, suitable for most masonry substrates
- Metal insulation discs: load-spreading washers used alongside drywall screws to secure boards where fire resistance is required
- Plastic insulation anchors: lightweight, non-corrosive options for fixing rigid boards to brick, block and concrete
Fixing length matters. The anchor needs to pass fully through the board and embed into the structural substrate behind it. A fixing that terminates in the adhesive bed or the insulation itself will not hold reliably over time. For most wall applications, choose a fixing at least 40-60mm longer than the board thickness to get adequate embedment into the masonry. Pair these fixings with anchoring resins where substrate conditions require a bonded mechanical fix.
These fixings work alongside the broader insulation system. If the boards being fixed are insulated plasterboard rather than external-facing boards, the plasterboard fixings range covers dedicated solutions for that application. For projects that also need wall anchors for structural connections, the anchors range is worth a look alongside. MacBlair offers trade account pricing and fast delivery across Northern Ireland.
insulation Fixings FAQ's
Not always. Metal round hammer-in fixings work well with rigid PIR boards because the board is firm enough to accept the fixing without compressing around it. Mineral wool slabs are softer, so load-spreading discs or washers are recommended alongside the fixing to distribute the clamping force and prevent the head pulling through the board face. Check the product datasheet for the specific fixing you are using to confirm compatibility.
For standard wall applications, five to eight fixings per square metre is a common starting point. Exposed locations, high-wind areas, or upper storeys typically require more fixings per board to resist wind uplift and board movement. For a standard 1200mm x 600mm board, around five fixings is typical, while a full 2400mm x 1200mm sheet may need twelve or more. Always follow the board manufacturer's fixing specification for the exact pattern required.
Some are, and some are not. Metal insulation fixings that conform to EN 13501-1 are fire rated and are required in certain applications, particularly where the insulation is part of an external wall system on buildings subject to stricter fire regulations. The product details will confirm whether a fixing carries this certification. If fire performance is a requirement on your project, check the specification before ordering and select fixings that explicitly state fire-rated compliance.
Metal fixings conduct heat more readily than plastic ones, which means they can create minor thermal bridges through the insulation layer at each fixing point. In most domestic wall insulation projects this has a negligible effect on overall thermal performance, but in high-specification builds or passive house projects it is worth considering plastic-pin anchors or thermally broken fixings to minimise the effect. Spacing fixings evenly and not over-fixing also helps limit the total area of thermal contact.