Polycell expanding foam 750 mlthis water resistant expanding foam from 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 the exact size of the cavity you need filling if youre using it during redecoration projects its sandable and paintable making it perfect for giving a smooth p