Design Buy Build Issue 42 2020 | Page 91

Rooflights Glazing options Once you have chosen the most appropriate material for your rooflight, you then need to consider the glazing options. Glazing can also be a tricky subject when specifying a rooflight, not least because there are so many different types of glass and glazing system available. Aside from thermal performance you need to decide if you need toughened glass, for additional safety and protection against falling objects. Toughened glass does not mean that it is suitable to walk on, so if you need to stand on a rooflight it will require specialist glazing. Self cleaning glass is another option. This technological breakthrough was introduced to the UK in 2002 by Pilkington, and is effectively the same as conventional glass, but with a specially developed coating on the outside, that once exposed to daylight, reacts in two ways. Firstly, it breaks down any organic dirt deposits through a photocatalytic process, and secondly, when it rains, instead of forming droplets, the water spreads evenly over the surface and takes the dirt off with it. It is kinder to the environment than ordinary glass and it is the ideal choice for situations where cleaning will be costly or difficult. You also have the option for double or triple glazing. This is probably fairly obvious, but you should always opt for triple glazing if budget allows as this will have a significant impact on the thermal performance of the rooflight. Few rooflight companies will offer triple glazing as standard, so be aware of this when you are gathering and comparing quotes. It is also possible to have solar control glazing, which incorporates invisible layers of special materials on the glass that has the dual effect of allowing sunlight in, while repelling solar heat. Allowing sunlight to pass through your 91 rooflight while radiating and reflecting away a large degree of the sun’s heat means that your indoor space stays bright and much cooler than would be the case if normal glass were used. Solar control glass is not necessarily coloured or mirrored glass, although such finishes can be applied for aesthetic purposes if desired. Conservation style rooflights If you have a Listed property or live within a Conservation Area, you may be restricted in the type of rooflight you are allowed to install and the chances are that you will need a traditional or conservation style rooflight that complies with strict building regulations. The legislation around conservation rooflights state that new openings should generally be kept to a minimum and should be of a simple form that respects the building’s character.