Mannok PIR boards

About Mannok

Mannok is a building materials manufacturer headquartered in Derrylin, County Fermanagh, in Northern Ireland. The business grew out of the Quinn Group and traded as Quinn Building Products until 2020, when it took the Mannok name at the end of a five-year investment programme. The name comes from Fear Manach, the Irish origin of the word Fermanagh.

Mannok makes its rigid PIR insulation at Scotchtown, Ballyconnell, County Cavan, a plant that has been producing polyurethane and PIR insulation since 2004. Since October 2024 the company has been majority owned by Çimsa, part of Turkey's Sabancı Group, with the local leadership team keeping a stake and the Mannok brand retained.

On certification, Mannok PIR insulation boards carry BBA Agrément certification for the UK market and NSAI Agrément certification in Ireland, and the company's management systems are certified to ISO 9001 for quality, ISO 14001 for environmental management and ISO 50001 for energy management. Mannok has a reputation for consistent, keenly priced PIR board that is widely sold through UK and Irish merchants and online suppliers.

Mannok PIR insulation boards: the general purpose specification

The Mannok PIR insulation boards we supply are the general purpose board: a rigid polyisocyanurate foam core with a low emissivity aluminium foil facing bonded to both faces. The board is 2400 x 1200mm, which gives 2.88m² of coverage per sheet, and it is made in thicknesses from 20mm up to 200mm. Every thickness has a declared thermal conductivity of 0.022 W/mK.

The foil facing does several jobs. It protects the foam during handling, it gives a clean flat surface for taping, and where it faces an unventilated air gap it improves the thermal resistance of the whole build-up. PIR itself is a closed cell foam, so it does not slump or settle the way fibrous insulation can.

Because the general purpose board is a universal product, the same board can go into a pitched roof, a flat roof, a floor or a wall. The only decision you need to make is the thickness, and that is set by the U-value you are trying to reach.

How PIR Boards supplies Mannok PIR insulation boards

PIR Boards sells one product line: general purpose 2400 x 1200 PIR insulation boards, foil faced both sides, 0.022 W/mK, in every thickness from 20mm to 200mm. Mannok is one of the manufacturers we supply to that specification, and we are open about how the shop works. You order a thickness, and we dispatch whichever brand is best stocked for your postcode on the day. That may be Mannok or it may be another maker's board built to exactly the same specification.

This is good for the buyer for three reasons. First, the thermal performance is identical. Every brand we supply has the same 0.022 W/mK conductivity and the same 2400 x 1200 board size, so your U-value calculation gives the same answer whichever name is printed on the foil. Second, it keeps the price down, because we are not tied to one factory's price list and can buy where stock is strongest. Third, it keeps lead times short, because a gap in one factory's output of a particular thickness does not hold your job up.

Order before 2:30pm on a working day and delivery is 3 working days on average, with dates varying by area and availability. Delivery is free on UK mainland orders over £450 + VAT. If an exact brand match matters to you, for example to tie in with Mannok boards already on site, ask us before you order; we cannot guarantee a particular brand will be sent.

Where Mannok PIR boards are used, thickness by thickness

Mannok PIR insulation boards are used throughout the building envelope, and the thickness you choose follows the application. The thin end of the range, 20mm, 25mm and 30mm, suits places where depth is tight: an insulated lining layer under rafters, a thermal break behind plasterboard on masonry walls, or upgrading a garden room or workshop.

At 40mm and 50mm the board becomes a true insulation layer. Typical uses are the under-rafter layer in a loft conversion, infill between timber frame studs, and insulation over a solid slab in a refurbishment where floor height is limited. From 60mm to 100mm you are in the workhorse thicknesses: 75mm to 100mm between rafters in a pitched roof, 100mm between floor joists or below a screed, and 90mm to 100mm in timber frame or masonry extension walls.

The thick end, 120mm to 200mm, is for warm flat roofs laid over the deck, new ground floors built to current Building Regulations, and extensions or garden rooms where you want to hit a low U-value in a single layer. Layers can also be combined, for instance 100mm between rafters with 50mm under them, which is a common loft conversion build-up.

Why 0.022 W/mK matters for your U-value

Thermal conductivity, written as lambda and measured in W/mK, tells you how readily heat passes through a material. The lower the figure, the better the insulator. Mannok PIR insulation boards are declared at 0.022 W/mK, which is among the best values available in a standard rigid board and roughly half the figure of common mineral wool products.

The practical consequence is thickness. Thermal resistance is thickness divided by conductivity, so 100mm of PIR board at 0.022 W/mK gives a resistance of about 4.55 m²K/W, where a wool product at 0.044 W/mK would need 200mm to match it. A U-value is the reciprocal of the total resistance of every layer in the construction, including plasterboard, air gaps and surface resistances, so the PIR layer is usually what decides whether you pass.

Because every brand PIR Boards supplies is declared at 0.022 W/mK, you can run your U-value calculation once, order the thickness it tells you, and the result stands whichever brand arrives.

Working out how many Mannok boards you need

Each 2400 x 1200 Mannok PIR board covers 2.88m². Measure the area to be insulated, divide by 2.88 and round up, then add about 10% for cuts and offcuts. A 60m² ground floor works out at 60 divided by 2.88, which is 20.8 boards, so 21, plus 10% for waste brings you to 23 boards.

For pitched roofs measure the slope, not the plan area, and remember that boards between rafters are cut into strips to suit 400mm or 600mm centres, which produces more waste than a flat floor. For walls between studs, measure the stud bay widths and allow for noggins.

Cutting, fitting and taping Mannok PIR insulation boards

Mannok PIR board cuts cleanly with a fine-toothed handsaw or a dedicated insulation saw against a straight edge. Boards up to about 50mm can be scored deeply with a sharp knife on both faces and snapped. Mark the foil, cut on a flat surface and wear a dust mask, gloves and eye protection, because PIR dust is irritating.

Between rafters or studs, cut the board a few millimetres over the bay width so it friction fits without gaps, and fill any remaining gaps with expanding PU foam. Keep the foil facing intact where you can. Tape all joints and board edges on the warm side of the construction with a foil-faced tape so the boards act as a continuous vapour control layer, and lap the tape onto any adjacent vapour barrier. Below a screed, lay the boards tightly butted on a level base with a separating membrane over them.

PIR is combustible and must not be exposed to flame or hot works. Inside a building it should be covered with plasterboard or another lining as required by the Building Regulations, and the relevant Approved Documents and the manufacturer's BBA certificate set the detailed rules for each application.

Storage, handling and delivery

Store Mannok PIR insulation boards flat on level bearers, off the ground, under cover and away from standing water. Keep the factory wrapping on until you need the boards, do not stack other materials on top of them, and protect the foil from scrapes and sharp tools. Large thin boards flex, so carry them on edge and use two people above 100mm.

Boards arrive by pallet to kerbside or the nearest hard standing. Check the quantity and thickness against your order before the driver leaves and report any damage straight away. Order before 2:30pm on a working day for delivery in 3 working days on average; dates can vary by area and availability, and delivery is free on UK mainland orders over £450 + VAT.