WINTEC® Winslot®

the passive sun control façade system
– thermal barrier, improves energy efficiency


Winslot® Blades (400mm wide) are precast in natural concrete, which offers a light louvered shelf to catchnatural sunlight and bounce it deeply into the interior space.


Winslot® is an integrated system including all the elements required. It offers the architect a comprehensivefenestration solution, by strategic spacing of blades (depending on latitude and orientation of the building)sunlight is controlled onto the façade and into the building envelope.


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

Download Catalogues & CAD Drawings

If you are specifying or designing with the Winslot® System download the handy ‘zip’ folder below. It includes all CAD drawings and catalogues for this system.


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

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.


Modulated on the 85 mm brick gauge vertically and on the 300mm module in plan a wide range of spatial solutions are possible.


The Winslot® System forms part of the load bearing brickwork employing pre-cast concrete elements.


Winslot® is an integrated system comprising all the elements required, including proprietary aluminium and glazing components.


By passive design, Winslot® Blades may be spaced to manage solar heat gain and bounced light into the interior.


Besides the horizontal louvres, the Winslot® Blades double as sills and lintels.


The Winslot® Blades protect all opening Winvent® inserts from rain at each level with a 275mm overhang and drip line.


A recess to receive Venetian or roller blinds forms an integral part of each Winslot® Blade ensuring no projection into the internal space.


All the Winslot® pre-cast concrete components are separated at the struck face, in the vertical plane by a thermal barrier between the inner and outer parts. In this way all exposed surfaces are smooth “off-the-shutter” concrete.


The precast concrete components; blades, reveals and mullions are all supplied as “off-the-shutter” products using very accurate steel moulds; no “struck faces” are visible as they are hidden by the building process. All aluminium Winvent® framing is supplied either in anodised or powder coated finish and factory glazed to the architect’s specification.


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 orizontally 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.

When specifying or pricing the Winslot® System remember...

…we always supply Winslot® as a complete Architectural System.

The Winslot® System includes precast concrete elements and the Winvent® glazing inserts in the various options are available. 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 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 Winvents® ranging in height from three to seven brick courses in 85mm increments.


(Definitions from SANS 10400-XA)


Area that includes glazing and framing elements that are fixed or movable, and opaque translucent or transparent.


Ratio of the heat gain entering the space through the fenestration area to the incident solar radiation. The higher the SHGC ratio the greater the amount of solar radiation entering the building.


The amount of solar radiation striking a surface per unit of time and area.


Thermal transmittance of the composite element, including the air space and associated surface transmittance. The U-Value addresses the ability of a material to conduct heat. The higher the U-Value number, the greater the amount of heat that can pass through that material. A lower value would mean a better insulator.

Winvent® - designed specifically for the Winslot® System

The Winvent® Glazing Inserts are specifically engineered to work perfectly with the Winslot® System.

Winvent® is SANS 10400-XA & SANS 613 Certified

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 both the Winblok® and Winslot® System on request – confirming compliance with SANS 10400-XA simulation and calculations according to National Fenestration Rating Council(NFRC) and ISO standards.

From Top-hung to Flyscreen to Louvre

Expertly engineered to work perfectly every time.

Winvent® Top-hung

The aluminium Top-hung projecting out Winvent® is supplied factory glazed (silicone flush glazing). It is manufactured from aluminium extruded sections, which are natural anodised or epoxy powder coated finished. Thehandle is cast aluminium which is then powder coated black. Weather seals are wool pile. The pantograph friction stays are manufactured from stainless steel. Fly screens and burglar bars may be factory fitted as additional accessories.

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). It is manufactured from aluminium extruded sections which has a natural anodised or epoxy powder coated finish. Weather seals are wool pile. The centre pivot hinge is a nylon friction bearing. Burglar bars may be factory fitted as an added accessory.

Winvent® Flyscreen

The Fly Screen 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 Fly Screen is only available as a factory fitted item. If loose Fly Screens are required for on-site fixing, the steel Fly Screen must be ordered.

Winvent® Bottom Pivot

The Bottom-Pivot inward opening Winvent® 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 tted as an added accessory.

Winvent® Glazed Louvre

The Glazed Winlouvre provides an opening window where projecting out, Central-pivot or Bottom-pivot Winvent® are impractical. An aluminium louvre blade mechanism is mounted in an aluminium Winvent frame. The blade mechanism and frame may be natural anodised or epox y powder coated. It may be fixed to Winblok® with the glazing rebate on the inside or outside of the building. Glazing may be 114mm blade widths of clear or obscure glass. Glazed Winlouvres may be used for ventilation in conjunction with Winguards or special burglar bars in high security applications. *Not recommended for Winslot®

Winvent® Fixed Louvre

Aluminium Winlouvres provide permanent fixed ventilation for squash courts, switch rooms, ventilation ducting and other similar applications. They will not totally exclude entry of wind driven rain. Aluminium Winlouvres are manufactured from extruded aluminum louvre blades carried on tubular mullions and mounted in an aluminium Winvent® frame. Aluminium Winlouvres may be supplied with a Flyscreen attached if required. *Not recommended for Winslot®

Winvent® Fixed Frame

The aluminium fixed frame Winvent® is designed to match the opening Winvent®. It is manufactured from aluminium extruded sections. It is supplied factory glazed (silicone factory glazing). Burglar bars may be factory fitted as an added accessory.

Winvent® Burglar Bars

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

Winvent® = 50% more light

The design and development of the Winblok® Total Window System in 1985 and most recently the Winslot® Passive Sun Control Fenestration System required an innovative solution for the provision of opening lights. As a result the Winvent® range of windows with an innovative central angle system allows the Winvent® to be bonded directly to either the Winblok® or Winslot® system – and in the case of the Winblok®, the glazing rebate can be on either the inside or outside of the building.

The Winvent® is designed as an integral part of the Winblok® and Winslot® 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 Winblok® 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) and the adjacent glazing (in the case of the sash) by introducing, back in 1985, the new concept of structural silicone bonding forglazing and concrete.

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