Thermal bridge

A building loses heat mainly through its weakest spots. Concrete columns and beams, the edges of a slab, balcony slabs that carry on outwards and the corners where wall meets ceiling all carry heat more easily than the rest of the wall. The same happens wherever insulationThermal insulationA layer of material that lets heat through only slowly, so a home keeps its warmth in winter and stays cool in summer. stops or leaves gaps.

In winter these spots are colder on the inside. The moisture in the air of the home turns to water on them, and that is where mouldMouldFungi that grow on damp surfaces, leaving black or greenish spots and a musty smell. It is a symptom of damp, not a problem with the paint. often appears: in the corners of the ceiling, around windows, in a strip along a beam. Mould like this isn't caused by a leak but by condensationCondensationMoisture in the air turning to water on cold surfaces such as windows, outside corners and ceilings. It is the most common cause of mould indoors..

Insulation that runs continuously over these spots reduces them. External wall insulationExternal wall insulation (ETICS)An external insulation system: insulation boards are glued and fixed to the outside walls, then covered with reinforced render and a finishing coat. covers the columns as well, and spray polyurethane foamSpray polyurethane foamA foam sprayed on as a liquid that expands on the spot and sets into one seamless layer. It insulates against heat and cold and closes cracks and joints. runs up the parapetsParapetThe low wall around the edge of a flat roof or balcony. The joint between it and the floor is one of the most common places for leaks. and covers the edges of the slab. When you discuss insulation, it's worth asking exactly where it will stop.