7.5% Discount for limited time only! Enter SKY75 at checkout


Related Products - View All

  • Flat Rooflight

    Buy Now
  • Opening Rooflights

    Buy Now
  • Brett Martin Roof Lanterns

    Brett Martin Roof Lantern

    Buy Now
  • Polycarbonate Rooflight Dome

    Buy Now
  • Brett Martin Access Hatch Roofloghts

    Glass Roof Access Hatch

    Buy Now
  • Flat Skylights Brett Martin

    Circular Rooflight

    Buy Now
  • Brett Martin Flat Skylights

    Buy Now
  • Electric and Manual Opening Rooflight by Brett Martin

    Buy Now
  • Mardome Trade Polycarbonate Roof Dome Window

    Mardome Trade Polycarbonate Roof Dome Window

    Buy Now

Made in UK

Thermal Performance

Building Regulation Compliance

Easy Fit


Electric Opening Flat Roof Polycarbonate Skylight

The Mardome Trade Dome Electric Hinged Vent Rooflight is the perfect flat roof solution to introduce natural light and ventilation. Thanks to its strong polycarbonate construction, this skylight is durable and reliable, providing a sophisticated yet affordable flat roof dome that can be operated electrically with a wall switch.

The flat roof skylight comes in a range of sizes, with glazing types and finishes available. All the flat roof domes are made right here in the UK – you can rest assured that you’re getting quality craftsmanship every time! The flat roof dome also features concealed single or tandem chain actuators (depending on size) for extra ventilation.

Bring your flat roof vision to life with the Mardome Trade Dome Electric Hinged Vent Rooflight. With its flat roof polycarbonate skylight, you’ll enjoy a strong and reliable flat roof solution with extra ventilation to boot. It's the perfect way to add natural light and airiness to any flat roof space. Contact us today for more information!

Fitting and Measurements

The product data sheet and instructions for installation in PDF form to download can be found at the foot of this page.

Please read the following installation instructions first.

Available Sizes

We offer a broad range of sizes from 600 x 600mm to 1800 x 1800mm in 150mm increments as standard. However, we can also accommodate bespoke dimensions; please get in touch with the sizes you need and we’ll be happy to provide expert guidance and discuss your options.

Builders Upstand Installation: How to Measure

Please refer to the diagram below for a guide on how to measure the dimensions of the external builders upstand.

Acceptable margin:

Fixed / unvented domes = dome size +20/-20mm
Opening / vented domes = dome size +40/-20mm

The height of the builders upstand should be 150mm and the wide 75mm, as seen in red on the diagram above. This means that the item you are purchasing from our menu should match the dimensions of your external timber.

For example, the purchased item should be 900 x 900mm and your external timber should measure 900 x 900mm. The external timber size can be seen on the diagram above in red marked “measure here”.

Domes With PVC Kerb: How to Measure

Please refer to the diagram below to see how to measure the internal opening of the roof.

Acceptable margin:

Dome size +20/-30mm

You can pick the dimensions you need for your timber size from our order menu. The timber size (which is the red measurement on the above diagram) is the same as your structural opening size and when buying with a 150mm/300mm upstand should match.

For example, if you purchase 900 x 900mm, your structural opening dimensions should also be 900 x 900m.

Fitting Video Guide

Fitting Video Guide


Glazing Details:

Glazing type thermal efficiency: refer to Centre Pane U-Value
Entire rooflight thermal efficiency: refer to Ud-Value

Note: depending on the dimensions selected, glass glazing may limit the choice of openings and cannot be offered with an access hatch.

In order to comply with Part L Building Regulations, a minimum U-value of 2.2w/m2K is required. In addition, triple skin rooflights (minimum) are recommended by the manufacturer in every installation.


The light transmission properties of the Reflex polycarbonate rooflight are displayed in the table below:

The qualities each type of tint offers is as follows:

Clear: High Visibility

  • Optimal light transmission
  • Improved visibility throughout the dome
  • Enhanced transparency

Opal: Solar Reduction and Diffused Light

  • Combines maximum generation of diffused light with privacy
  • Reduces solar heat gain and blocks solar glare
  • Minimises visibility through dome

Patterned: Enhanced Privacy

  • Enhances transmission of light while protecting privacy
  • Minimises visibility through dome

Bronze: Solar Reduction

  • Minimises heat gain and solar glare
  • Delivers lower light transmission


Opening/Vented Builders Upstand

A uPVC frame is provided with this dome which attaches onto the top of all the opening equipment, ventilation and builders upstand.

150mm uPVC

Delivers 150mm waterproofing and insulation and can be mounted at the level of the roof surface.

Note: the specification will determine the final kerb profile.

300mm uPVC

Delivers 300mm waterproofing and insulation and is usually mounted below the level of the roof surface.

Trickle Vents

8400mm² equivalent area ventilation is provided via two hit and miss trickle vents (manually operated).

Note: 450mm x 450mm cannot be supplied with trickle vents.

Electric actuators (where fitted): one-year guarantee
Unit: 10-year guarantee

Actuators are designed to last a minimum of 10,000 cycles. Although a ten-year guarantee applies to the unit, the lifespan is expected to be significantly longer with no perforation, distortion, loss of weather-tightness or deterioration in structural efficiency for approximately 20 years.


The production time for this item is usually 2-3 days provided it is ordered in one of the sizes below:

  • 450 × 450
  • 600 x 600
  • 750 × 750
  • 900 × 600
  • 900 × 750
  • 900 × 900
  • 1050 × 600
  • 1050 × 750
  • 1050 × 1050
  • 1200 × 600
  • 1200 × 900
  • 1200 × 1200
  • 1350 × 1050
  • 1350 × 1350
  • 1500 × 1050
  • 1500 × 1500
  • 1800 × 900
  • 1800 × 1200
  • 1800 × 1800

The production time is increased to 5 days for any items which include remote and rain sensors. Deliveries to Ireland will also take longer; please get in touch for more information.

Please ensure that on delivery there is a suitable person present who is able to unload the items from the lorry. The driver will be unable to assist in any way or deliver the items inside. This is due to insurance purposes.

Any equipment or installation arrangements should be made after the item has been successfully delivered.


TB189 Installtion Opening Rooflight
Mardome TB200 data sheet