Oversills
These sills are designed to work with external insulation and give the appearance of a traditional stone or concrete sill.
Our oversill has an excellent insulation value, this improves the overall insulation value of a building by reducing the cold bridging at the point where the sill and window meet.
A Passive sills oversill is a perfect addition to any external insulation project give you a traditional appearance it also has far superior acoustic properties than an aluminium sill during heavy rain and hailstone.
Our oversills are available in our standard sandstone, white granite and grey granite stone-effect finishes, or in our hybrid finish, which has a white paint primer coat and is ready to be painted any colour you choose.
Product Gallery
Why choose Passive Sills
✓ Complies with all building regulations
✓ Best for thermal efficiency
✓ Super lightweight
✓ Quick and easy to install
✓ Lower carbon footprint
✓ Best for manual handling
✓ Competitive cost when installed
✓ 10 year warranty
Installation Videos
Watch oversills being installed – these videos explain the installation process of our passive oversill so you can do it yourself at home.
Contact us if you require more details or view more videos on our Installation Videos page.
Covering a broken window sill with an insulated oversill
Installing an insulated oversill on an external wall insulation build
Technical Drawings
Stone finishes
Sandstone 
White Granite 
Grey Granite
