Can dry lining improve wall insulation?

Yes. Insulated plasterboard adds thermal insulation to external walls. For the uninsulated solid 9-inch brick walls typical of Maidstone's Victorian terraces (Maidstone central, Bearsted and Loose), a 50-80mm insulated plasterboard (PIR or phenolic) can reduce U-values from around 2.1 W/m²K to 0.30 W/m²K, meeting current Part L retrofit targets.

Three common insulation options for Maidstone properties:

• PIR (polyisocyanurate): best thermal performance per mm, ~0.022 W/mK, thinnest build-up
• Phenolic foam: marginally better than PIR, ~0.018-0.020 W/mK, more expensive
• Graphite EPS: cheaper, ~0.030 W/mK, slightly thicker board required

We typically recommend PIR for Maidstone retrofit work because the thinner build-up minimises room loss, particularly important in small terraced kitchens and bathrooms.