A standard fine-tooth handsaw provides a clean cut through both the plasterboard and the insulation layer. Alternatively, you can use a sharp utility knife to score the plasterboard face, snap the board along the line, and then cut through the foam backing.
Insulated Plasterboard and Thermal Drylining
Insulated plasterboard combines a standard sheet of drywall with a layer of rigid foam insulation, creating a single board that provides both a wall finish and thermal resistance. These boards are widely used on internal solid walls, pitched roofs, and cold flat ceilings to improve the energy efficiency of a property. By merging drylining and insulation into one step, installation times are significantly reduced. The insulation core is typically made of PIR or phenolic foam, offering low thermal conductivity to help meet modern building regulations.
Rather than cutting and fixing separate materials, attaching these combined boards to timber battens creates a reliable, level structure for insulating internal walls. When mechanically securing the boards to this wooden framework, using appropriate drywall screws ensures a firm hold without damaging the paper face of the plasterboard. The boards are available in various overall thicknesses, allowing for flexibility depending on the available room space and the required thermal resistance.
When applying the boards directly to bare masonry walls, a suitable plasterboard adhesive provides a strong bond through the dot and dab method. Once the boards are securely fixed in place, the gaps between them must be properly finished. Applying jointing tape over the seams and covering the surface with a continuous coat of skim plaster results in a smooth, flat wall that is ready for painting or wallpapering.
Insulated Plasterboard FAQ's
Yes, you can fix these boards directly to bare masonry walls using adhesive. Building regulations require the addition of secondary mechanical fixings once the adhesive has set to ensure the boards remain secure in the event of a fire.
Most insulated plasterboards include a built-in foil vapour control layer positioned between the plasterboard and the foam insulation. This integrated layer prevents moisture from passing through the wall, reducing the risk of interstitial condensation without needing a separate membrane.
When applying insulated boards to a ceiling, you must mechanically fix them directly into the timber joists above. Ensure the screws are long enough to penetrate through the board and at least 25mm into the structural timber for a secure hold.
Yes, you can apply tiles directly to the paper face of the board. However, it is important to consider the weight limits. A bare plasterboard surface can support heavier tiles compared to a wall that has been skimmed with plaster. Ensure the boards are mechanically fixed to the wall or timber frame to carry the additional weight safely.