Established 1893 | BS 460:2002 Certified | UK & International Supply | Expert Technical Support | 0333 987 4452
Established 1893 | BS 460:2002 Certified | UK & International Supply | Expert Technical Support | 0333 987 4452
For the complete picture, from consent and specification to installation and care, see our conservation rooflights and skylights guide.
If you’ve already researched and know you need conservation rooflights for your project, you probably found various options online. So, what exactly is a conservation rooflight, and are they all the same?
The history of this sort of glazing and the reasons for its popularity in period homes and contemporary builds are essential to comprehend what makes a rooflight a conservation style.
The idea of converting an unusual area into a bright home would be frightening without the innovative invention of the rooflight. Hence, the conservation rooflight might be regarded as a hugely influential architectural element, as it has provided the construction industry with a means of bringing in natural light.
Although rooflights (or skylights) have been present for millennia, they took off in the Victorian era as technology advanced and architectural ambitions were raised. The Crystal Palace, constructed in 1851, was one of the most well-known Victorian buildings. It included expansive panes of glass to demonstrate what could be accomplished at the time.
Mass-produced Rooflights in Victorian homes were frequently fabricated from cast iron, and early examples had thinner, less substantial panes of glass. In addition to technological constraints, excise charges based on glass weight introduced in the middle of the 18th century also contributed to the shortage. These multi-paned glass rooflights were narrow and flat, so they didn’t protrude from the roof at all. Nowadays, many individuals aim for this sleek minimalism in their glazing projects.
As a result of their widespread use, numerous manufacturers have released conservation roof windows into the market, making it challenging to select the best option without first learning how to dissect the various options. Identifying what makes a rooflight a “real” duplicate of a Victorian conservation rooflight is a valuable technique.
The ideal profile for a simple conservation design would be low and sleek, like a roof. Many skylight manufacturers aim to make conservation rooflights with modern, hefty aluminium profiles that protrude from the roof. Steel is the go-to material for genuine conservation rooflights thanks to its high strength, low profile, and high glass-to-frame ratio.
Steel frames vary in grade and in the paint system that protects them, so ask each maker which steel they use and what corrosion rating the coating carries, especially for exposed or coastal sites.
Many conservation rooflights are finished inside with a natural timber liner rather than painted board. Ash and oak are common choices, and some makers offer other species or a paint-ready lining. The inside component of your conservation rooflight will look sleek and cosy thanks to natural wood.
Rooflight manufacturers and retailers typically utilise softer woods or plastics with a white-painted inside finish, which might lead to deeper frame profiles or smaller viewing areas because of the liners. While white internal frames are typically associated with modern flat rooflights rather than classic conservation items, their sterile appearance is a selling point.
Single glazing was typical for Victorian rooflights, but modern construction standards are far more stringent; therefore, single glazing no longer suffices (Part L). Because of advancements in glazing technology, current double-glazed units can give various benefits while still being very slim, making them the most popular choice for genuine conservation rooflights. A sound specification typically combines a self-cleaning outer pane, solar control and a low-emissivity inner pane for thermal efficiency. Look for warm-edge spacers, an argon gas fill and a UV-stable edge seal.
While triple glazing does give a slightly better thermal performance, it does so at the price of beauty, which is why some conservation rooflight suppliers are quick to talk about it. Every decent triple-glazed unit will be over 50% thicker than a double-glazed one due to the optimal spacer bar thickness of 16mm. Although a flush-fitting profile was once a primary condition for a conservation rooflight, triple glazing has rendered this nearly impossible for several roof types.
To maintain the authentic Victorian aesthetic, the conservation officer may typically insist on a glazing bar in a conservation rooflight. Getting conservation rooflights may only sometimes be necessary, but it’s wise to double-check before making a purchase.
A real glazing bar should be used if a conservation rooflight calls for one. Here you can tell the difference between manufacturers making authentic-looking reproductions of Victorian rooflights and those trying to pass off contemporary skylights as antique. For something to be considered a “glazing bar,” it must do more than just separate the panes of glass; it must also reinforce the casement. Many rooflights installed for conservation purposes have unsightly additions affixed to the exterior glass using glue or adhesive., a viable option for making a modern rooflight with a bulky framed profile suitable for a historic building.
Again, a top-hung profile will be used if you want a close imitation of a Victorian rooflight. With a top-hung style, the casement doesn’t protrude into the room, creating additional floor space below. While modern plastic knobs are out of reach and add little to the interior decor, smaller top-hung rooflights use lovely brass ironmongery to control the casement.
Although these products may be advertised as “conservation rooflights,” not all construction styles can benefit. The conditions for adopting conservation rooflights are significantly stricter if your building is Listed or in a conservation area. You should always acquire approval, not just for their usage but also for the manufacturer you wish to use.
You should also enquire about how long the supplier or manufacturer has been trading, and because of the complexity of the product, you should avoid poorly experienced manufacturers.
To help the UK achieve its carbon-neutral goal, every effort must be made to cut energy use. Since they allow in so much natural light, roof windows save energy by minimising the need for artificial lighting. Increasing the amount of natural light in your house has many benefits, including improved mood, reduced stress, and a reduced risk of disease.
Increasing the size of your rooflights is one method to do this, but is this the best option? You should constantly check what the finished visible (commonly referred to as evident viewable) area of the rooflight will be to provide adequate lighting, as this is not necessarily the case even if you have a large rooflight. If the frame of a conservation rooflight is 900 millimetres wide and 1200 millimetres high, you might assume that all such rooflights have the same clear viewable area. However, this is not the case; rooflights with thick, modern frames or flat rooflights disguised as pitched conservation styles admit much less light.
Choosing the right conservation rooflight is easier with expert help. Tuscan Foundry does not make rooflights: we supply cast iron rainwater goods for listed and period buildings, and we refer rooflight enquiries to two specialist makers, The Rooflight Co. and Clement. Both make steel conservation rooflights with genuine glazing bars, in standard and bespoke sizes.
For a step-by-step reference covering consent, specification, installation and care, see the conservation rooflights guide in the Building Restoration Index. If the roof is being opened up anyway, it is also the right moment to check the gutters and downpipes; a site survey can cover both.
Not necessarily — the finished visible (viewable) area matters more than the overall frame size, since rooflights with thick, modern frames or flat rooflights disguised as pitched conservation styles admit much less light.
Most are steel, with a factory paint or powder-coat finish and a timber or paint-ready internal lining. Ask the maker for the steel grade and the corrosion rating of the coating, particularly for coastal or exposed sites.
It helps the UK towards its carbon-neutral goal by reducing the need for artificial lighting, and more natural light also brings benefits such as improved mood and reduced stress.