A line of Mackridge natural ridge ventilators in-situ on a roof in Todmorden


Roof mounted natural exhaust ventilators specifically designed to fit along a building ridgeline. Units can be sited along the ridge as single units or joined together to form continuous runs.

Options include shut off dampers, bird guards together with fire and smoke release capabilities.


To provide a means of exhaust for extraction of warm, stale or contaminated air from a building.

In any natural ventilation scheme involving conventional industrial buildings the optimum position, under normal circumstances, is to provide a system of air extraction through the highest point of a building – the roof apex.

The Mackridge is a natural Ventilator designed specifically for mounting along the ridgeline of a building.

It can be manufactured in single unit or continuous form, to suit any pitch of roof and can be fixed to any type of sheeted or decked roof.

The relative position of the Ventilator along the roof apex maintains the longitudinal symmetry of the building appearance, unlike many other types of natural ventilators.

The Ventilators are offered in a range of materials and colours to colour match or contrast with the roof claddings. Each Ventilator is custom made to suit individual requirements with a variety of functional and control options.

Design and Installation Flexibility

With such a wide range of throat opening widths and lengths, together with the option of employing either undividual units or continuous runs, design and installation options are endless.


Available in a wide range of standard throat widths from 152mm to 914mm, units are made-to-measure in lengths and configurations to suit your requirements.

Aerodynamic Testing

The unit was subjected to a series of independently controlled tests to determine the aerodynamic performance of the design.

Aerodynamic co-efficient – 0.24


Aluminium alloy units weigh 18-70kg
Plastisol steel units weigh 28-104kg

Materials & Finishes

The most commonly used materials are:-

  • Mill finish aluminium
  • Plastisol coated steel
  • PVDf coated steel

Other materials and finishes include:- Aluminium with a polyester powder paint finish (including Syntha Pulvin) with a wide choice of colours and gloss levels.

Steel units manufactured using galvanised steel in mill finish or with a polyester powder paint finish.

Pre-coated units manufactured using a wide range of coated aluminium and steel substrates including HPS200 & Prisma.


  • Joining kits to form continuous runs
  • Bird guards
  • Insect mesh
  • Internal closure trim flashings
  • Security guards
  • Fusible Link Shields – for use in sprinklered buildings

Functional option

  • Permanently venting.
  • Controllable ventilation – by means of operable internal damper.


Manual Nylon covered wire cable to:

  1. Clam Cleat/Clutch Control – variable setting.
  2. Winch – variable setting.
  3. Friction loaded – variable setting.

Pneumatic For day to day opening and closing, also enables optional connection to smoke detection and building management systems.

Fusible Links These can be fitted in conjunction with any of the above control options to provide overriding release. Alternative temperature rated links are available.

Electro-Magnets These retain the damper in the closed position until de-energised by remote signal. Units fitted with electro-magnets require manual re-setting.

Electric Actuation For day to day opening and closing, also enables optional connection to smoke detection and building management systems.


Dampers (where fitted) are pivoted on double bush nylon bearings. Maintenance should be carried out in accordance with McKenzie-Martin’s recommendations.

System Design & Product Selection

Assistance with scheme design and product selection is offered by our experienced technical team.