This work should be carried out on the outside of the insulation layer, of external walls, roof and ground floor, especially at critical junctions, such as at roof eaves, attic trap doors, chimneys/fireplace, dormer roofs and attic conversions, caulking and taping joints between block work walls and window frames. Also, opening sashes of windows and doorframes not draught-sealed, gaps around pipes, cables and cavity block walls that are dry-lined on the inside.