Soprema Sopratherm PL4000 Insulated Plasterboard - 1200mm x 2400mm

• Thermal Performance - Good thermal performance with a thermal conductivity of 0.022 W/m.K, reducing the thickness of insulation required to hit the target U-value.
•  Time Saving - SOPRATHERM PL4000 brings together both insulation and plasterboard creating a 2-in-1 solution to insulate and dry line walls or roofs at the same time.
• Easy to Install - SOPREMA boards are rigid assisting with ease of transportation, handling and fitting.
• BBA Certified - SOPRATHERM PL4000 has been assessed by the BBA as fit for use in plasterboard thermal laminate applications if installed, used and maintained as set out in the certificate. Please read the BBA certification page for full details and restrictions.

Roof Applications

Pitched Roofs (Between and Below Rafters):

Soprema insulation boards are well suited to pitched roof constructions, including loft conversions and the thermal upgrade of existing roof spaces. Installed between and beneath rafters, they help achieve strong thermal performance while keeping rafter depths to a minimum, allowing valuable internal headroom to be retained.

Flat Roofs (Balconies and Terraces):

For flat roof areas beneath balconies or terraces, Soprema solutions support the creation of an effective warm roof build-up. By limiting heat loss through the roof structure, they contribute to improved thermal continuity and long-term energy efficiency across the roof deck.

Flat Roofs (Between and Under Joists):

Soprema boards can also be fitted between and below joists in flat roof constructions, providing a space-efficient method of insulation while maintaining a clean internal finish. Their practical format supports straightforward installation and can help reduce overall installation time on site.

Wall Applications

Cavity Walls:

Soprema insulation is suitable for enhancing the thermal performance of cavity wall constructions, particularly in refurbishment projects where preserving internal room dimensions is important. The slim board profile allows effective insulation to be added without significant loss of usable space.

Timber Frame Walls:

In timber frame buildings, Soprema insulation boards are fixed to the internal face of the frame, delivering reliable thermal performance alongside an integrated internal lining. This approach can simplify the build process by reducing the number of installation stages required.

Solid Walls:

For solid wall properties, Soprema provides an internal insulation option that is applied directly to the inner wall surface. This method improves thermal efficiency while offering a ready-to-finish internal surface, making it well suited to retrofit and renovation projects.

What are the main applications of Soprema insulated plasterboard?

Soprema insulated plasterboard is commonly used in internal wall and ceiling applications across both residential and non-residential buildings. It is designed to improve thermal performance when installed on solid walls, masonry backgrounds, or framed constructions, helping to reduce heat loss and improve overall energy efficiency.

Are Soprema insulated plasterboard products environmentally responsible?

Soprema insulation products are engineered to deliver effective thermal performance, which can contribute to reduced operational energy demand in buildings. As with many rigid insulation materials, environmental impact should be considered across the full product lifecycle. Soprema provides technical guidance to support appropriate specification, use, and end-of-life management.

What sizes and formats are available?

Soprema insulated plasterboard is available in a range of thicknesses and board sizes to suit different project requirements and performance targets. Products are typically supplied as rigid composite boards to allow for straightforward handling, cutting, and installation on site.

How is Soprema insulated plasterboard fixed?

Soprema insulated plasterboard can be installed using either adhesive bonding (commonly referred to as dot and dab) or mechanical fixings to timber battens or metal studwork. When using adhesive, bonding compound is applied in spaced dabs before positioning the board. For mechanical fixing, appropriate fixings should be used to ensure the board is securely fastened and level prior to finishing.

Is an air gap required behind insulated plasterboard?

In most wall applications, an air gap is not required behind insulated plasterboard. However, certain constructions — such as roof or ceiling applications — may require ventilation gaps to manage condensation risk. Always follow project-specific design requirements and Soprema’s installation guidance.

Should joints be taped?

Yes, joints between boards should be sealed using suitable foil or vapour-resistant tape. This helps maintain continuity of the insulation layer, improves airtightness, and reduces the risk of heat loss or moisture ingress at board junctions.

Does insulated plasterboard require a vapour control layer?

Many Soprema insulated plasterboard products incorporate an integral vapour control layer, meaning a separate membrane is not usually required. Where a product does not include a VCL, or where the installation is in a high-humidity environment, an additional vapour control layer may be necessary.

Can Soprema insulated plasterboard be dot and dabbed?

Yes, Soprema insulated plasterboard can be bonded directly to suitable solid backgrounds using the dot and dab method. The substrate should be clean, dry, and structurally sound before installation. Once fixed, the boards can be finished in the same way as standard plasterboard.

Should insulated plasterboard touch the floor?

It is recommended that insulated plasterboard is installed with a small clearance from the floor, typically around 10mm. This gap helps prevent moisture transfer from the floor into the board and is normally concealed by skirting or sealed as part of the finishing process.

What thickness of insulated plasterboard should be used?

The required thickness will depend on the target U-value, available space, and compliance with Building Regulations. Thicker boards provide improved thermal performance but require more space. Selection should always be based on the specific construction type and performance requirements of the project.

Can moisture pass through insulated plasterboard?

Insulated plasterboard offers resistance to moisture vapour but is not fully waterproof. In areas with high humidity or limited ventilation, additional moisture management measures may be required. Products with an integrated vapour control layer help reduce the risk of condensation, but persistent damp conditions should be addressed through appropriate building design and detailing.

Why use insulated plasterboard on ceilings?

Using insulated plasterboard on ceilings can significantly reduce heat loss to unheated spaces, improving comfort and energy efficiency. It combines insulation and plasterboard into a single product, simplifying installation and reducing build-up thickness. Insulated plasterboard can also provide acoustic benefits, making it suitable for applications such as loft conversions or rooms beneath unheated voids