Polycell polyfilla expanding foam 750 mlthis water resistant expanding foam from the polyfilla range by polycell has been specially designed for filling sealing and insulating most building materials around the interior and exterior of your home simply apply and leave for 20 minutes to dry it comes in an easily storable and transportable aerosol and expands to 45 times the can volume if youre using it during redecoration projects its sandable and paintable making it perfect for giving