• Winslot®
    the passive sun control façade system
    A creative fenestration solution
    Innovative built-in thermal barrier
    Greatly improves energy efficiency

Creativity meets function in the newest way to façade.

Modular, Load Bearing, Fenestration System with Integrated Passive Sun Control, Sills and Lintels, Rain Protection and Thermal Barrier.

A Complete Solution

Winslot® is an integrated system including all the elements required. It offers the architect a comprehensive fenestration solution controlling sunlight onto the façade and into the building envelope.

Bounced Light

Winslot® Blades (400mm wide) are precast in high-strength concrete, which offers a visually slim louvered shelf to catch natural sunlight and bounce it deeply into the interior space.

Interior Climate Control

The combination of precast elements with integrated thermal barriers and Winvent® glazing solution, are spaced to optimise sun control offering a high degree of energy efficiency and insulation.

Download catalogue and CAD files for this system.

All neatly packaged in a handy "zip" folder that contains everything you need.


Winslot® is a complete system.

Winslot® is always supplied as a complete architectural system, including the precast concrete elements and the Winvent® glazing inserts in the options available as one complete system.

This system has been painstakingly designed, tested and approved and is a comprehensive passive sun control facade system. Therefore specifying or pricing this system should always include the Winslot® elements plus the Winvent® insert. This is to ensure that the system will function correctly for many years and perform exactly as it has been specifed by the architect, which in turn guarantees that the client is getting only the very best Winslot® solution for their project.

The Winslot® Concrete Components

Precast high strength, high density, low permeability concrete.

winslot blades
winslot reveals columns mullions
winslot blades lengths

Winslot® Straight Assembly

Winslot® straight assembly is a vertical stack of straight blades consisting of sill, intermediate louvres and lintel that are held in place by left and right reveals spacers inset and built into the wall at each end. For long spans, a mullion can be used for additional support. The number of intermediate blades may vary according to the design. Stepped DPC must be built in to stop water penetration. The openings between the blades can be glazed with various combinations of Direct Glazing and Winvent® glazing inserts.

winslot blades lengths

Winslot® Construction Guide

Detailed video visualizing the process of building with the Winslot® System.

Our Winvent® range

Specifically designed and engineered to integrate perfectly with the Winslot® System.


Winvent® Top-Hung

The aluminium Top-hung projecting out Winvent® is supplied factory glazed (silicone flush glazing). Manufactured from aluminium extruded sections, which are natural anodised or epoxy powder coated finished. The handle is Injection Moulded, Glass Fiber Reinforced PA 6 Nylon in black. Weather seals are wool pile. The pantograph friction stays are in stainless steel.
Fly screens and burglar bars may be factory fitted as additional accessories.

Please contact us to order or check stock availability within South Africa.


Winvent® Fixed Frame

The aluminium fixed frame Winvent® is designed to match the opening Winvent® Top-Hung. Manufactured from superior quality aluminium extruded sections. As with the Top-Hung, it is supplied factory glazed (silicone factory glazing).
Burglar bars may be factory fitted as additional accessories.

Please contact us to order or check stock availability within South Africa.


Winvent® Fixed Direct Glass

We have developed one of the most cost-effective ways to allow light into the building. A pane of glass (no aluminium) is directly installed into the glazing rebate of the Winblok® frame using our SPM40SG Hybrid Sealant.

Any type of glass can be used for this application, the Architect is to specify the glass type required.


Winvent® Central Pivot

The aluminium central pivot Winvent®, designed for high level pole action with a pull ring spring catch, is supplied factory glazed (silicone flush glazing) and is manufactured from aluminium extruded sections which has a natural anodised or epoxy powder coated finish. Weather seals are wool pile and the centre pivot hinge is a nylon friction bearing.
Burglar bars may be factory fitted as additional accessories.

Please contact us to order or check stock availability within South Africa.


Winvent® Bottom Pivot

The Bottom-Pivot Winvent® inward opening is designed to be used where projecting out, or a Central-Pivot Winvent®, may be inappropriate. This Winvent® is supplied with a pull ring spring catch and comes factory glazed (silicone ush glazing). It is manufactured from aluminium extruded sections which are natural anodised or epoxy powder coat finished. Weather seals are wool pile. The Bottom-Pivot is set 100mm from the bottom and has a ‘stop’ attached to limit the opening width.
Burglar bars may be factory fitted as additional accessories.

Please contact us to order or check stock availability within South Africa.


Winvent® Flyscreen*

The Flyscreen for the Winvent® is manufactured from an aluminium extrusion frame into which a fibre mesh is secured with a rubber gasket. It is top hung on the frame with glass-reinforced nylon hinges and opens inwards secured by a catch.

*The Flyscreen is only available as a factory fitted item.

Please contact us to order or check stock availability within South Africa.


Winvent® Burglar Bars

Winvent® Burglar Bars are manufactured from 12 x 10mm solid aluminium bars, and factory fitted with countersunk pop rivets as an added accessory.

Please contact us to order or check stock availability within South Africa.

sans-certs sans-certs

Winvent® is SANS-10400XA & SANS 613 Compliant

Our Winvent® Top-Hung and Fixed-Frame windows are compliant with both SANS 10400-XA (energy performance) and SANS 613 (air and water ltration/penetration).

We are able to provide the Simulated Energy Performance Rating Certification for all design permutations using the Winvent® Inserts in the Winslot® System on request – confirming compliance with SANS 10400-XA simulation and calculations according to National Fenestration Rating Council(NFRC) and ISO standards.

Comparative Advantages

Winslot® Standard*
Timber Winblok®
Allows for the control of direct sunlight
Provides bounced light into the interior
Glazing after wet-work to eliminate damage and theft during construction
Provides an integrated lintel
Provides an integrated sill
Low maintenance
Supplied as finished product
Reduces need for high performance glass to control solar heat gain
Reduces need for structural glass due to reduced height of vertical apertures
Reduces the need for deeper structural aluminium sections
Glazing requires no mechanical fixing, silicone installed
Provides a rebate to receive a Venetian / Roller blind
Supplied with thermal barrier
Provides an integrated drip line which enhances waterproofing

*Compared to standard aluminium casement windows

Modular, Integrated Passive Sun Control Fenestration System

Manufactured from high density, low permeability concrete.

The Wintec® Winslot® system is designed to offer the architect a comprehensive fenestration solution which allows, by strategic spacing of blades, depending on latitude and orientation of the building, the control of sunlight onto the facade and into the building envelope.







sun control






window dressing






Architectural Considerations: Fenestration is the architectural mediator between the interior and exterior via the building envelope. The human eye is prone to scan horizontally and easily interrupted by the vertical intervention. Winslot® is oriented horizontally to reduce vertical interruption but offers deep sun protection and bounced light into the interior space. Viewed from the exterior, the thin horizontal elements express clean lines without undue vertical interruption to the façade.

Solar Heat Gain Comparative


Sun Angles & Energy Efficiency

The diagrams below illustrate the effect of the solar control at summer solstice, spring/autumn equinox and winter solstice angles on a north facing façade at a latitude of 30° South with spacing of 5 brick courses. The Winslot® vertical components include Reveals, Mullions and Winvent® inserts, ranging in height from three to seven brick courses in 85mm increments.


Winvent® = 50% More Light!

Winvent® is designed as an integral part of the Winslot® and Winblok® systems that we are able to back by technical support service including National Building regulations and thermal performance certificates.

The relatively small aperture size in a Winslot® required that width in elevation of the Winvent® frame be reduced to a minimum. This was achieved by designing a section that borrowed its structural strength from the adjacent concrete (in the case of the frame) section and the adjacent glazing (in the case of the sash) by introducing, back in 1985, the new concept of structural silicone bonding for glazing and concrete.

This technology allowed the Winvent® System to be bonded directly into the Winslot® System without mechanical fixing and resulted in a width of only 35mm as against 65mm of conventional aluminium glazing systems.