Key Features Of Fenea Lipped Casement Windows

Aluminium lipped casement windows, also known as stormproof windows, are outward-opening windows where the sash overlaps the frame to create a protective “lip.” This design was historically developed to improve weatherproofing over traditional flush casements.

Today, lipped aluminium casements are used widely in residential and commercial developments – from new-build housing and apartment blocks to schools and offices – offering a blend of modern performance and classic aesthetics. They are valued for their robust weather resistance, thermal efficiency, and design versatility, making them a popular choice for architects, builders, and developers seeking durable, high-spec window solutions.

Exceptional Weather Resistance

The overlapping sash design provides an extra layer of sealing against wind and rain, earning the “stormproof” name for its ability to keep out drafts and moisture. Modern casement systems are tested to stringent standards (e.g. BS 6375) for air permeability, water-tightness, and wind load – Fenea’s windows achieve high ratings such as Class 4 air tightness and Class E water resistance, suitable for the UK’s harsh weather conditions.

High Thermal Performance

Aluminium casement frames now incorporate advanced thermal breaks (insulating barriers within the aluminium) to reduce heat transfer. This means aluminium lipped windows can achieve low U-values (around ~1.0–1.5 W/m²K depending on glazing), helping meet Part L building regulations for energy efficiency. For example, Fenea’s systems can reach Window Energy Ratings of A or B with double or triple glazing, keeping buildings warm while minimizing energy bills.

Strength & Durability

Aluminium is a robust, long-lasting material that does not warp or rot, offering a lifespan measured in decades with minimal maintenance. Lipped casement designs in aluminium benefit from the metal’s strength – allowing slimmer frames that still withstand heavy use and wind loads. Our systems are Kitemarked and security-tested to PAS 24 standards, meaning they resist forced entry and can comply with Document Q requirements for secure new dwellings.

Slim Sightlines & Aesthetics

With their inherent strength, aluminium frames support larger glass areas and slimmer sightlines than bulky uPVC or timber equivalents. This maximizes daylight and provides a sleek, contemporary look appreciated in modern architecture. At the same time, we offer a range of profile styles – from traditional ovolo or chamfered sculptured beads to clean square-edged profiles – allowing the windows to complement either heritage-style projects or sharp modern designs. A broad palette of durable powder-coated colour finishes (including dual-colour options) is available to match any design scheme.

Security and Compliance

Quality aluminium casement windows come with multi-point locking systems, internal glazing beads, and robust frames that together provide a high level of security. Fenea’s systems are tested to PAS 24 and the police Secured by Design standards for enhanced security. This means they can be used to satisfy Document Q requirements for new-build security. Additional features like hinge protectors and lockable handles further improve. Specifying an aluminium window that is Document L and Document Q compliant ensures your project meets both energy and security regulations without compromise.