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Roof Lights – Less is More?

Thursday, 29th June 2017 | by: Cameron Weights

At the time of writing the UK has just experienced the hottest Summer Solstice on record and the hottest June day in 40 years. Those of us sat inside are no doubt struggling to concentrate let alone write an interesting blog post relating to architecture! Most of you will no doubt be questioning this post in agreement that there is no such thing as too many roof lights.

Now I must take this chance to fully endorse the use of roof lights as they provide solutions to problems of lighting and ventilating areas, when designed properly they can provide an aesthetic feature and can even make a space seem bigger, but we as designers must be careful not to indulge too much.

Open roof lights in theory have been in use since ancient Roman times such as the oculus of the Pantheon in Rome. Glazed ‘closed’ skylights have been in use since the Industrial Revolution, however, it is since the mid-20th century that mass production of units has seen skylights brought into prominent use. Since then, their uses and design have changed dramatically.

Residential Use

It is suggested that natural light can penetrate a space by approximately 3.00m but this is dependent on factors such as the window design, the angle of the window and the size and the surrounding areas. Roughly speaking it is safe to assume the same for natural ventilation also, which is a point worth noting when we realise that windows account for the majority of our passive ventilation.

The number, size and position of roof lights is a conversation that I have on nearly every project, whether that be the number of roof lights on the front elevation of a loft conversion or what size of roof light the client would like in their new rear extension.

Rear/side extensions are the most common projects that we are involved with and they will usually involve a ‘wrap-around’ extension to turn a standard Victoria ‘L-shaped’ property into a rectangular footprint. My first thought when considering a project of this type is lighting the inner areas of the property such as the original rear reception room and kitchen as these rooms are essentially moved to the middle of the floor space. It is here we are able to implement roof-lights to great effect. I am yet to have a client who does reply with ‘more roof lights and can they be bigger’, as you can always have more and of course they can be bigger but it necessary?

Points to Consider

Going back to an earlier point, with ventilation and lighting it is natural to want more but we must be aware that these new roof lights will not be our only source of either. A bi-fold door arrangement is being used in nearly all of the projects I work on – these provide huge amounts of light and ventilation so I stress to my clients that there is such a thing as too-much natural light.

Another point worth considering is the idea of over-heating a space, too often we see designs where glass is thrown at a project because ‘it looks cool’. The UK has taken huge leaps in increasing the quality of our glazing, double glazing is now a minimum requirement in new work and what it does incredibly well is keeping warm air in, this can quickly become an issue when we don’t want to keep this warm air in such as during a heat wave.

Unsurprisingly the final point is cost related. Simply put, a window cots more per metre than traditional construction whether that be in a wall or a roof. Roof-lights are complex units that require special attention to waterproofing, mechanics and installation. They also alter the entire structure around the opening so ensuring that we are happy with the design prior to looking at the structure is of paramount importance, your builder or your budget will not be happy if a late change is required because proper care wasn’t taken at design stage.

Final Say

As is becoming a feature in my design work, it is the smaller factors that require the more thought – this is largely due to the negative knock on effects if they are not thought through. In this instance, a small-minded approach to something like roof-lights could lead you to being sat in a room which is too hot, too bright and cost you a lot more money than it needed to.

If you are looking to extend your property and wish to discuss our architectural services please do not hesitate to contact a member of the architecture team by email or call 020 7183 2578 (option 4).