Recticel PIR boards

About Recticel and Recticel Insulation

Recticel is a Belgian group with its headquarters in Brussels and its shares listed on Euronext Brussels. Its history goes back to 1778, when Jan-Frans Cooppal set up a gunpowder mill at Wetteren on the River Scheldt. Cooppal merged into the PRB group in 1967, and in the 1970s the Recticel name, taken from a small Dutch polyurethane company within PRB, was adopted for all of the group's polyurethane activities. Recticel sold its Engineered Foams business to Carpenter Co in 2023 and is now a focused insulation group, with Recticel Insulation as the lead brand in its portfolio.

In the UK, Recticel Insulation UK Ltd manufactures PIR at Enterprise Way, Meir Park, Stoke-on-Trent, Staffordshire. The plant opened in 2008. Before that Recticel imported boards from Belgium, and the Stoke-on-Trent site was built to supply UK customers from UK production. The site employs around 125 people and applied to expand its facilities in 2025.

Recticel Insulation's management systems are assessed by Lloyd's Register and certified to ISO 9001:2015 for quality and ISO 14001:2015 for environmental management, and its PIR boards hold BBA Agrément certification covering pitched roofs, framed walls and floors. Recticel PIR insulation boards have a long-standing reputation with UK merchants, specifiers and roofing contractors for consistent quality and dependable supply.

Recticel PIR insulation boards: the general purpose specification

The Recticel PIR insulation boards we supply are the general purpose board: a rigid polyisocyanurate foam core faced on both sides with a low emissivity aluminium foil. Each board is 2400 x 1200mm, covering 2.88m², and the range runs from 20mm to 200mm thick. Every thickness carries the same declared thermal conductivity of 0.022 W/mK.

The double foil facing protects the core during handling, gives a flat clean surface for taping, and adds to the thermal resistance of the construction where it faces an unventilated cavity. PIR is a closed cell foam, so the board is rigid, light and dimensionally stable. It will not sag between rafters or compress under a screed, and its performance does not fall away over time.

Because the general purpose board is designed for use anywhere in the envelope, the same board serves a pitched roof, a flat roof, a floor or a wall. The thickness is the only variable, and it follows from the U-value you need.

How PIR Boards supplies Recticel 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. Recticel is one of the manufacturers we supply to that specification, and we are straightforward about how it works. You order a thickness, and we dispatch whichever brand is best stocked for your postcode on the day. That might be Recticel or it might be another manufacturer's board built to exactly the same specification.

The buyer gains in three ways. The performance is identical, because every brand we supply shares the same 0.022 W/mK conductivity and the same 2400 x 1200 board size, so a U-value calculation gives the same answer regardless of the name on the foil. The price is lower, because we buy where stock is strongest rather than being tied to a single factory. And lead times are shorter, because a shortage of one thickness at one plant does not stop your order going out.

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 you need Recticel boards specifically, perhaps to match Recticel PIR insulation boards already fitted, ask us before ordering; we will tell you what is possible but we cannot guarantee a particular brand.

Typical uses for Recticel PIR boards by thickness

Recticel PIR insulation boards go into every part of the building envelope, and the thickness follows the job. At 20mm, 25mm and 30mm the board is a thin thermal layer: an under-rafter lining in a loft conversion where headroom is precious, a thermal break behind plasterboard on a masonry wall, an upgrade to a garden room or garage, or a packer to deal with a cold bridge around an opening.

At 40mm and 50mm the board carries real insulation value and is used as the under-rafter layer in a two-layer roof, as infill between timber frame studs, and over a solid floor in a refurbishment where depth is limited. From 60mm to 100mm you reach the most common thicknesses: 75mm to 100mm between rafters in a pitched roof, 100mm between floor joists or beneath a screed, and 90mm to 100mm in the walls of a timber frame or masonry extension.

Between 120mm and 200mm the board is used for warm flat roofs over a deck, new ground floors designed to current Building Regulations, and extensions and garden rooms where one layer needs to achieve a low U-value. Layers can be combined, for example 100mm between rafters and 50mm beneath them, which is a familiar loft conversion build-up.

What 0.022 W/mK means for your U-value

Thermal conductivity, or lambda, measured in W/mK, describes how easily heat passes through a material; the lower the number, the better the insulation. Recticel PIR insulation boards are declared at 0.022 W/mK, one of the lowest figures available in a standard rigid board and about half that of typical mineral wool.

In practice that means thinner build-ups. Thermal resistance is thickness divided by conductivity, so 100mm of PIR board gives roughly 4.55 m²K/W, a figure that mineral wool at 0.044 W/mK would need 200mm to match. The U-value of a wall, roof or floor is the reciprocal of the sum of the resistances of all its layers, including linings, cavities and surface resistances, and the PIR layer usually decides whether the target is met.

Since every brand PIR Boards supplies is declared at 0.022 W/mK, one calculation covers every brand. Order the thickness the calculation gives you and the result holds whichever board is delivered.

Working out how many Recticel boards you need

A 2400 x 1200 Recticel PIR board covers 2.88m². Measure the area to be insulated, divide by 2.88, round up, and add about 10% for cuts. A 45m² flat roof is 45 divided by 2.88, which is 15.6 boards, so 16, and with 10% waste you would order 18.

On a pitched roof, measure along the slope rather than the plan. Boards fitted between rafters or studs are cut into strips to suit 400mm or 600mm centres, so waste runs higher than on a floor, and a room with many openings or dormers justifies a 15% allowance.

Cutting, fitting and taping Recticel PIR insulation boards

Recticel PIR board cuts with a fine-toothed handsaw or an insulation saw run along a straight edge, and boards up to around 50mm can be scored on both faces with a sharp knife and snapped. Cut on a flat surface, keep the blade square so edges butt tightly, and wear a dust mask, gloves and eye protection.

Between rafters or studs, cut each piece a few millimetres oversize so it friction fits, and foam any gaps with expanding PU foam. Keep the foil as undamaged as possible. On the warm side of the construction, tape every joint and edge with a foil-faced tape so the layer of boards acts as a continuous vapour control layer, and lap it onto any adjoining membrane. Under a screed, lay the boards tightly butted on a flat base with a separating layer above.

PIR is combustible. Keep the boards away from flames and hot works, cover them internally with plasterboard or another suitable lining, and follow the Building Regulations Approved Documents and the manufacturer's BBA certificate for the detailed requirements of each application.

Storage, handling and delivery

Store Recticel PIR insulation boards flat on level bearers, under cover, off the ground and clear of standing water. Leave the factory wrapping in place until the boards are needed, keep other materials off the stack and protect the foil from scrapes. Thin full-size boards are flexible, so carry them on edge, and use two people for 100mm and above.

Deliveries arrive on a pallet to kerbside or the nearest hard standing. Check the thickness and count before signing and report any damage immediately. 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.