Roof Windows, Roof Lights, Sky Lights and Light Tunnels


roof windows1stAssociated can provide help and advise with regard to structural defects reports for things like problems with your roof, window problems, dampness, lateral dampness, condensation, cracking, movement. We carry out building surveys, structural surveys, property surveys, structural reports, engineers reports, home buyers reports or any other property matters.

As you can see from this article we sketches and also photos in all our survey reports as the feedback we have from our clients is that the sketches and photos help them understand the reports.

We, of course, like to meet you at the property during the survey and we are more than happy to talk to you about the reports.

Please free phone 0800 298 5424 for a friendly chat with one of our surveyors.

A window with many names

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Two roof windows


We are going to look at problems with windows in roofs, but the first problem is the many names that it has. It is probably most commonly known by its trade name of velux windows or velux, who are a popular manufacturer of this type of window. It is also known as a roof light or sky light. Where this type of window is used on a pitched roof, inserted into the roof structure and follows the pitch of the roof, it can be flush or slightly above the level of the roof tile. Where it sits on a flat roof it tends to be above the level of the roofing material. A roof window can come in a variety of shapes and sizes which include the flat roof window just mentioned or domed roof windows, or even barrel shape.


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When are roof windows used?

To increase natural light to an area

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A circular roof window viewed from the inside out


In modern properties they are commonly used to add light into a room, often one that forms part of an extension, such as where a property has been extended to the rear, or up into the roof area. Sometimes it is used because it is the only way of getting light into the area economically, other times they are used where there is a planning requirement, perhaps not to overlook a neighbour or to follow the existing roof line.

In older properties they tend to be above stair wells adding natural light to the stair area, where the is often no natural light from windows.



Add ventilation to an area

We have also seen roof lights where one of the main functions is adding ventilation to the area. This could be in a shower room or in the kitchen area, to give light to aid cooking.

Giving access

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We have also seen it used, and indeed we have used them, to give access to other roof areas, for example in a valley gutter situation. Adding a roof window to the valley gutter would give access to clear leaves and hopefully stop blockages and leaking roofs.





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A later Georgian wire plated glass roof window


We have been unable, from our structural surveys over the years, to find a history of roof windows, but from our surveys we believe the very first roof windows used sections of glass set in line with the slates. We have also seen some glazed tiles that are exactly the same as the tile the roof is made out of and these are likely to have been the earlier sorts of roof windows.



A roof window within a frame

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A triangular shaped roof window with a timber frame and rolled lead to the ridge


We have seen many different roof windows over the years set within frames. By this we mean within a frame that holds the window in place. We have seen many different types over the years when carrying out building surveys.






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Barrelled roof window

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Barrelled roof window

The original ones, we would take an educated guess, were formed of wood and glass, possibly lead was used to cover the timber to minimise deterioration. Most recently we have seen them produced in metal coated with a plastic and also plastic. This allows for different shapes, such as a dome or a barrel.






Shapes formed within the roof light itself

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Shaped plastic roof light

Modern materials allow the shape of the roof light to be formed within the material itself, for example the photo shows a plastic domed roof light, which stops the water from sitting on it.




Light tunnels

We have seen a few of these, sometimes they are hard to distinguish between an electric light from within the property, but outside you will see a circular dome. This has reflective material that takes it down a tunnel, forming a tunnel of light that can then be seen inside .


You may also be interested to read our other article on problems with roof windows, roof lights and sky lights:


Problems With Roof Windows, Roof Lights and Sky Lights


roof windowsIf you truly do want an independent expert opinion from a surveyor with regard to roof windows, roof lights, velux roofs, dormer, dormer roofs, roof problems, chimneys, surveys, building surveys, structural reports, engineers reports, specific defects report, structural surveys, home buyers reports or any other property matters please contact 0800 298 5424 for a surveyor to give you a call back.

If you have a commercial leasehold, freehold, etc, then you may wish to look at our Dilaps Website at and for Disputes go to our Disputes Help site .

We hope you found the article of use and if you have any experiences that you feel should be added to this article that would benefit others, or you feel that some of the information that we have put is wrong then please do not hesitate to contact us (we are only human).

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