Interior Wall Insulation

Interior Wall Insulation

When the outside cannot change

In conservation areas, on listed buildings, terraces and flats, insulating the outside of the wall is often not an option. Internal wall insulation (IWI) adds insulated plasterboard or a framed insulation system to the inside face of the external walls. It costs less than external insulation and can be done room by room, but the moisture risk is higher and it needs careful design.

What the survey covers

• Wall construction and current moisture condition, including any penetrating or rising damp
• The right insulation type for the wall, including breathable systems for older solid walls
• Thickness versus lost floor area, and how to handle skirtings, sockets, radiators and window reveals
• Cold bridging at floor and ceiling junctions and party walls
• Ventilation and condensation control once the room is better sealed
• Sequencing with other works such as rewiring, replastering or new windows

What you receive

A room-by-room specification and sketch details that a builder or plasterer can follow, together with a clear note of any preparatory repairs. Where appropriate the survey is carried out to PAS 2035 as part of a whole-house retrofit assessment.

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