Polycarbonate Dome Skylights
How do I measure and choose the right size Mardome Trade Roof Light?
When ordering a dome for a pre-existing upstand, it is important to measure the external dimension from the outside edge of the upstand. For example, an outside upstand measuring 600 x 600 will require a dome with a minimum size of 600 x 600.

When ordering a dome with an upstand, it is important to measure the internal dimension from the inside edge of the internal hole of the roof. For example, an internal hole measuring 600 x 600 will require a dome with a maximum size of 600 x 600.

How do I Install the Mardome Trade Roof Light?
The Mardome Trade Is very easy to install. First, the kerb is screwed down to the deck using suitable fixings. Once the kerb has been weathered, you can continue to attach the dome using the provided self-sealing screws. A full installation guide can be downloaded under the technical data tab
Do Mardome Trade roof lights comply with building regulations?
Mardome Trade roof lights are available in Single, Double and Triple skin. To comply with Part L Building regulation, a triple skin dome must be used.
Will a Polycarbonate Dome roof light make my room cold?
Polycarbonate Dome roof lights are available in Single, Double and Triple skin. To reduce heat loss, we recommend that a triple skin dome be used. This has a U-value of 1.8 W/m2K and complies to building regulations.
Are Mardome Trade roof lights available in bespoke sizes?
Mardome Trade roof lights are only available in set sizes. If you require something a bit more tailored, we recommend upgrading to a Skyseal Flat Glass Fixed Rooflight.
What is the difference between single, double and triple skin?
Single, Double and Triple skin refers to the number of layers used when forming a dome skylight. A triple skin dome will comply to building regulations and because it has a higher U-value, it will keep your home warmer.
U-values for each are listed below:
Single - 5.5 W/m2K
Double - 2.7 W/m2K
Triple - 1.8 W/m2K
Do I need Trickle Vents for my roof light?
Vents are an excellent way to reduce condensation occurring on the inside of your dome. For high moisture areas, such as bathrooms and kitchens, we highly recommend the addition of Trickle vents.
What opening options are available with Mardome Trade roof lights?
Manual Opening, Powered Opening, Access Hatch and Smoke Vents are available in the Mardome Trade range. Please see our full product range if you are interested in any of these options.
What is a U-value?
Thermal transmittance, also known as U-value, is a measure of heat loss through the structure. It is measured in W/m2K. The lower the value, the better the insulation.
The UK Building Regulations require a maximum of 2.2 W/m2K in existing dwellings and an average of 1.2 - 1.7 W/m2K for new dwellings on rooflights.
Any other questions?
Ask our team of inhouse experts who will be happy to have a chat and help you with your enquiry.