Cavalok
Cavalok is manufactured by Eurocell, the UK’s largest uPVC manufacturer, distributor and recycler. Eurocell has operated since 1974 and acquired Cavalok as part of its building products division.
Cavalok cavity closers are made from 100% recycled uPVC. The profiles provide a rigid template for bricklaying and window or door installation while sealing the cavity at openings. Subframes UK is an approved fabricator for the Cavalok range, supplying welded and mechanically jointed frames from 50mm to 300mm cavity widths.
The Cavalok system meets Part L 2021 and 2025 requirements and is Future Homes Standard compliant. For projects requiring fire protection, the FlameBlok profile provides 60-minute fire rating to BS476. Browse our cavity closer range to compare Cavalok with other profiles we fabricate.
For quotations, product information or technical support please call us on 01773 590100 or email sales@subframes-uk.com
FAQs
Are Cavalok cavity closers energy efficient?
Cavalok profiles use a polystyrene insulation core that meets Part L thermal requirements. The standard Cavalok profile is BBA certified with thermal resistance values suitable for SAP calculations.
BigBlok is Cavalok’s profile for wider cavities (125mm and 150mm) and low-carbon buildings. It achieves higher thermal resistance for projects targeting improved energy performance beyond minimum Building Regulations requirements.
Will Cavalok cavity closers work with a timber frame?
Cavalok works with timber frame construction using a frame hanger system. The hangers support the cavity closer from the internal frame before the external skin is built. This suits timber frame projects where wider cavities (typically 150mm to 300mm) require support during construction.
What are the benefits of Cavalok cavity closers?
Cavalok profiles are manufactured from 100% recycled uPVC with a polystyrene insulation core. The system is compatible with uPVC, timber and aluminium window and door frames.
Technical specifications include Part L 2021 and 2025 compliance, Future Homes Standard compliance and BBA certification. Fire-rated options (FlameBlok) are available for Part B compliance where required.
What is a cavity closer used for?
A cavity closer seals the cavity wall at window and door openings. Without a cavity closer, the gap between inner and outer leaves creates a thermal bridge where heat escapes and moisture can enter.
Cavity closers serve three functions: preventing thermal bridging to meet Part L requirements, stopping moisture ingress for Part C compliance and (with fire-rated profiles) providing fire stopping for Part B compliance. They suit masonry, timber frame and steel frame construction.
Do you need cavity closers?
Building Regulations Part L requires thermal bridging to be addressed at junctions including window and door openings. Cavity closers are the standard method for achieving compliance at these locations. SAP assessments include thermal bridging calculations, and using BBA certified cavity closers with documented psi values simplifies the compliance process.
What are cavity closers made from?
Most cavity closers use uPVC profiles with an insulated core. Cavalok uses recycled uPVC with polystyrene insulation. Other manufacturers use different insulation materials. Kingspan Kooltherm cavity closers, for example, use phenolic insulation for higher thermal resistance in the same profile depth.
Are cavity closers necessary?
For new build projects, cavity closers are required to demonstrate Part L compliance at window and door openings. Building control will expect to see an appropriate thermal bridging solution at these junctions. Retrofit projects may also benefit from cavity closers when replacing windows in cavity wall construction.
What is the purpose of cavity closers?
Cavity closers close the cavity at openings to maintain the thermal envelope. The insulated profile bridges the gap between inner and outer leaves, preventing cold bridging that would otherwise occur at window and door reveals. This maintains consistent internal surface temperatures and reduces condensation risk at these junctions.
What are the best cavity closers?
The right cavity closer depends on your project requirements. Cavity width, thermal performance targets and fire rating requirements all affect product selection.
Subframes UK fabricates cavity closers from 50mm to 300mm using Cavalok, Dacatie, Kingspan and Timloc profiles. We supply 2, 3 or 4-sided frames in standard configurations or bespoke shapes including arches, circles and ovals. Standard, fire-rated (up to 60 minutes) and structural options are available.
For quotations or technical advice on product selection, contact us on 01773 590100 or email [email protected].
