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
What dome finish options are there?
Our Dome roof lights are available in three different finishes:
Clear: For maximum daylight.
Textured: For better privacy and good daylight.
Opal: For maximum privacy but with reduced daylight.
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.
Does the Mardome Trade roof light come with a warranty?
Yes, all Mardome Trade Roof Lights come with a 10-year manufacturer's warranty.
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.
Do I really need a Triple Skin dome?
On paper, Triple Skinned polycarbonate domes are the ideal choice for modern homes and can offer U-values as low as 0.6 W/m²K. However, opinion is divided on whether triple skin has any real thermal impact in the home. Quite often they do very little to reduce your utility bills and the initial costs far outweigh any savings.
What is Light Transmission?
Light Transmission is the percentage of visible light that passes through a skylight's glazing, with higher percentages allowing more natural daylight into your living space, potentially reducing the need for artificial lighting and creating a brighter interior environment.
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What is Solar Heat Reflection?
Solar Heat Reflection measures a skylight's ability to return solar energy to the atmosphere rather than allowing it to enter your home, with higher percentage values indicating greater effectiveness at keeping interior spaces cooler during warm weather.
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What is a U-value?
U-value, or thermal transmittance, is a crucial measurement that quantifies how effectively a building element prevents heat from escaping or entering a structure. Measured in Watts per square meter Kelvin (W/m²K), this standardised value is particularly important when evaluating the thermal performance of skylights and roof windows.
The U-value specifically indicates the rate of heat transfer through a building component – in this case, a Rubber4Roofs skylight. The lower the U-value, the better the thermal insulation properties and the more energy-efficient the skylight will be. This translates directly to improved temperature regulation in your home and potential savings on heating and cooling costs.
Current UK Building Regulations establish specific U-value requirements for various building elements to ensure energy efficiency standards are met. For skylights and roof windows, existing dwellings must achieve a maximum U-value of 2.2 W/m²K, while new construction projects typically require more stringent values between 1.2 and 1.7 W/m²K, depending on the specific application.
Our premium skylight range exceeds these regulatory requirements, with models featuring advanced glazing technologies that deliver exceptional U-values as low as 0.9 W/m²K in some configurations. This superior thermal performance contributes to reduced energy consumption, a smaller carbon footprint, and enhanced comfort through consistent interior temperatures regardless of external weather conditions.
Any other questions?
Ask our team of inhouse experts who will be happy to have a chat and help you with your enquiry.