Internal insulation lining

Insulation applied on the inside: a dry lining — metal frame, insulation and a facing board — set against the existing wall, with a vapour control layer on the warm side. It is the way to insulate when external insulation is not possible (protected façades, condominiums, single units): fast, clean and reversible, and quick to warm because it works on the inner side. It must, however, be designed with care for moisture, because it moves the dew point inwards.

An internal insulation lining brings the insulation inside the building, set against the inner face of the perimeter wall. It is built dry: a metal frame fixed to floor and ceiling, the insulation in the cavity and one or two facing boards. It is the answer when nothing can be done outside.

Insulating from inside leaves the existing wall cold, and the dew point moves inwards, often right behind the insulation: here the vapour migrating from the room can condense. This is why a vapour control or barrier layer on the warm (inner) side is essential, or a capillary-active insulant (calcium silicate) that manages moisture without a barrier. It is the critical point of the system.

Internal insulation cannot carry on past the floors and the cross walls: at those junctions heat «escapes» and thermal bridges form, where the inner surface stays cold and at risk of mould. They are mitigated by returning the insulation a short way onto the cross walls and detailing carefully around windows and roller-shutter boxes.

The system is fast, clean and does not touch the façade: ideal for single flats. As it eats into the available space an efficient insulant must be chosen. By decoupling the board from the masonry, and with a fibrous quilt, it also improves the acoustic insulation — provided no rigid bridges are made that cancel the effect.