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Made in UK

Thermal Performance

Building Regulation Compliance

Easy Fit


Mardome Manual Opening Plastic Roof Window

The Mardome Trade Manual Opening Dome rooflight is the ideal solution for projects that require a plastic opening rooflight. Available in different sizes, this manual hinged vent also offers a range of glazing types and finishes to meet your specific requirements. The window can be wound open and closed by hand via an operating pole.

This dome offers many features as standard, such as robust construction, outstanding thermal insulation properties and excellent resistance to weather conditions - making it the perfect choice for kitchens, bathrooms or any other space you would like included with natural light from above.

For maximum convenience, the Mardome Trade Manual Opening Dome is easy to install and does not require any special tools or electric parts for installation. It's also easy to maintain, thanks to its long-lasting protective coating.

Make the most of your space and let in natural light with this Manual Opening Polycarbonate Roof Window from Mardome. With a versatile selection of sizes, glazing types and finishes, you'll be sure to find the perfect rooflight for your project!

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 selection 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/-20mmThe 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.


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 qualities 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 fitted with trickle vents.


Production for this item is usually 2-3 days provided it is ordered in one of the sizes listed 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 once the item has been successfully delivered.


TB200 Dome Rooflight Data Sheet
TB188 Installation Mardome Trade