Soudal Genius Champagne Gap filling expanding foam 750 ml. This 750ml water resistant fast curing gap filling expanding foam from the Genius range by Soudal has been specially designed for improving thermal & acoustic insulation & eliminating drafts or thermal bridges around the interior & exterior of your home. Simply apply & leave for 1½ hours for a bead of 3cm to dry. It comes in an easily storable & transportable aerosol & expands to Approx. 30 times the size of the can. If you're using it during redecoration projects it's sandable & paintable making it perfect for giving a smooth professional finish once dried.