External Cut Out and Re-seal Wexham Park Hospital by National Sealants. Posted on January 9, 2017 09 Jan External Cut Out and Re-seal Wexham Park Hospital PROJECT LOCATION Wexham Park Hospital, Slough PROJECT BACKGROUND External Cut Out and Re-seal of Expansion Joints using Fire Rated Sealant External Mastic Sealant Grays Inn Road, London Mastic Sealant St Johns Road Uxbridge