35mm Unilin Thin-R PIR Insulation Board

Unilin Insulation (formerly Xtratherm) now carries the Unilin brand.

35mm Unilin Thin-R Insulation Board (2400mm x 1200mm x 35mm) is an ultra-thin PIR rigid foil-faced polyisocyanurate thermal foam insulation solution suitable for multiple applications including roofs, walls, floors, timber and steel-framed construction.

About

This 35mm PIR board delivers exceptional thermal performance with a certified thermal conductivity of 0.022 W/mK, making it ideal for pitched roof insulation projects on ventilated, hybrid or warm roof systems. The ultra-thin profile minimises impact on internal space whilst achieving outstanding U-values and thermal bridging performance. Pitched roof insulation is particularly critical as roofs represent a major source of heat loss in buildings. This board combines excellent thermal resistance with practical installation benefits—it's lightweight, easy to cut and fit, fire-resistant, water-repellent and environmentally responsible.

Product Details

Thickness: 35mm

Length: 2400mm

Width: 1200mm

Overall Thickness Options: 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, 45mm, 50mm, 60mm, 65mm, 70mm, 75mm, 80mm, 90mm, 100mm, 110mm, 120mm, 130mm, 140mm, 150mm, 160mm, 165mm

Maximum Board Weight: 0.45 kg/m²

Thermal Resistance: 1.59 m²K/W

Thermal Conductivity: 0.022 W/mK

Compressive Strength: >150 kPa

Water Vapour Resistivity: >100 MNs/gm

Density (Foam Core): 30-32 kg/m³

Surface Spread of Flame: Class 1

Reaction to Fire: E

Finish: Aluminium Foil Facings

Applications: Roofs, Walls, Floors, Timber & Steel Frame

ETA Notification: Yes

Features: Versatile ǀ High-performance ǀ Rigid

Warm roof insulation construction offers an effective solution for insulating complex roof designs. By insulating above or between roof timbers, the building structure remains at internal environmental temperatures, reducing thermal stress and condensation issues.

Store 35mm PIR insulation on a clean, flat, covered surface away from ground contact. Polythene wrapping alone does not provide adequate outdoor protection. Take care during storage and on-site handling to prevent damage. These insulation boards cut easily with a sharp knife or fine-toothed saw.

Key Facts

1. Achieves A+ rating under the BRE Green Guide
2. Certified Lambda value of 0.022 W/mK
3. Minimal intrusion into living space
4. Reduced condensation risk
5. Low-emissivity foil facings
6. Lightweight and straightforward to install
7. Excellent thermal bridging performance
8. Suitable for ventilated, warm and hybrid roof systems

Browse our Unilin range and filter by thickness or coverage using the left-hand menu. For project suitability advice or bulk quotations, contact us on +4402038839057, email sales@insulationbee, or use Live Chat for the best UK insulation prices.