FAQs

What does window size mean?

Dimension of the window is in relation to the outer size of the frame in centimetre – it is not a size of the glass. For example a window 78×98 means 78 cm width and 98 cm height of the frame.

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Do I need a flashing kit?

Yes. Flashing is an integral part of the window. Some of the elements of the flashing are fitted to the window. Do not buy window without the flashing.

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Do I need window with the ventilation slot?

No, however, ventilation slot supports air circulation and it is very handy during the hot summer time, especially in converted attics where ventilation may be limited.

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What type of the flashing do I need?

Description of the Optilight window clearly states what type of flashing will be required. TZ flashing is a universal type and will fit any kind of roof material, however for slate and very thin materials we recommend TL flashing. It will assure the best possible roof finish. In case of plain tiles best use the TL flashing as well. If you’re still unsure please contact us. We will recommend the best flashing for your application.

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Is the Optilight roof window a Velux window?

No. Optilight roof window is supplied by Kronmat and it is one of the most popular roof windows in UK, backed by 10 year warranty for timber windows and 20 years warranty for PVC windows.

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What roof opening is required for Optilight roof window?

Roof gap should be 2-4 cm ( on each side) bigger than the size of the window.
I.E. for window 78cmx98cm recommended gap would be 82-86 cm x 102-106cm.

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Will I be able to install the window myself?

Yes. Optilight roof windows are supplied with the manual which clearly describes step by step how to install the window. Click here to see a video tutorial.
Installation of our windows should be carried by qualified roof installers.

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Do I need a PVC window?

No. Optilight Timber wood windows are very durable and covered by 10 years warranty however, they may require maintenance in the future depending on a level of the humidity inside. We would recommend Optilight PVC windows in bathrooms and high level humidity rooms. PVC windows have a white finish inside. Timber Optilight windows have a wood finish but we are offering range of timber windows painted in white as well.

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Do I need TH flashing?

TH flashing is designed for very thick roof materials. Please measure thickens of your tile first using the following method. Put a tile on a flat surface and measure distance from the surface level to the highest point of the tile. If the measurement exceed 45 mm – it’s possiible you still don’t need TH as it also depends on the roof angle. Please call us so that we can assist you.

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Recommendation:

Please follow provided manual step by step with corresponding flashing.
Use only parts supplied with the window. Do not replace any parts of provided flashing or fitting. Use only the original flashing screws.
Do not install Optilight roof window on a flat roof.
We recommend to have the window installed by qualified roof installers.

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