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 hybrid finish, which has a white paint primer coat and is ready to be painted any colour you choose.

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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 a Passive Sills Oversill on External Wall Insulation

Technical Drawings

Oversill technical drawing and dimensions.

Technical Model


Our Finishes

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