Conservation rooflights
Contents |
[edit] Background on conservation rooflights
Although rooflights (or skylights) have been around for centuries, they became more prominent during the Victorian era as technology and building aspirations were stretched and roof glazing boomed. One of the most famous Victorian building projects was the Crystal Palace, which, in 1851, used glazing on an unprecedented scale to showcase just what could be achieved.
Mass-produced Victorian rooflights for residential use tended to be made from cast iron, and the earliest examples would have smaller, lighter panes of glass. This was partially down to limits of glass technology at the time but also because of excise duties, which were imposed on glass by weight in the mid-18th century.
These slim, single glazed rooflights with multiple panels of glass were unobtrusive in design and sat flush in the roof.This resulted in their popularity, which has continued over the decades.
[edit] Features of modern conservation rooflights
There are now many types of conservation roof windows on the market. However, authetic replicas of conservation rooflights have certain attributes.
[edit] Low profile
Genuine conservation designs should be manufactured with slim clean lines and a low-profile to match the roofline. Most authentic conservation rooflights are manufactured from steel because it provides great strength while offering a slim profile and excellent glass to frame ratios. There are many types of steel conservation rooflights and for unrivalled protection and lifespan.
[edit] Wood
Some conservation rooflights are finished with real wood linings. American ash is the most popular choice, although other types of timber can be used. The use of real wood gives a neat, warm appearance to the internal element of a conservation rooflight.
[edit] Finish
While some rooflight suppliers use soft wood or plastic that is painted white as an internal finish, these liners can result in deeper frame profiles or reduced viewable areas. A white internal frame can be sold as ‘clean’ or ‘neat’, but these can sometimes produce a finish more often associated with modern flat rooflights than traditional conservation products.
[edit] Glazing
Victorian rooflights would have been single glazed, however, modern building standards are much higher and so single glazing does not meet the minimum requirements for thermal efficiency (Part L). Double glazing is now the most popular option for genuine conservation rooflights because glazing technology is such that a modern double glazed unit can provide a number of benefits while remaining reasonably slender.
Some conservation rooflight suppliers offer triple glazing for improved thermal performance, it can come at the expense of appearance. With a flush fitting profile being one of the main requirements of a conservation rooflight, the introduction of triple glazing makes that almost impossible on some roof types.
[edit] Glazing bars
Conservation officiers sometimes specify that a conservation rooflight should have a glazing bar to replicate that original Victorian appearance. It is not always the case, but it is definitely worth checking before making a purchase.
If a glazing bar is required, then it should be a genuine one. A genuine glazing bar should be something which not only divides the glazing but also provides additional strength to the casement. A stuck on glazing bar is one step up from a felt pen but certainly should not be seen as a way to make a modern bulky framed profile meet the criteria of a conservation rooflight.
[edit] Top hung
A top hung profile not only offers a more authentic appearance, it maximises the space below because the casement doesn’t stick into the room. Smaller top hung rooflights also utilise beautiful brass ironmongery to operate the casement whereas centre pivot designs tend to rely on modern plastic handles, which are out of reach and offer nothing to enhance the internal aesthetics.
[edit] Additional factors
Just because something is sold as a conservation rooflight, that doesn’t automatically make it suitable for all building types. For listed buildings - or those in a conservation area - then the criteria for using conservation rooflights may be more strict. There are only a handful of companies that specifically make conservation rooflights and even fewer who design, manufacture and assemble in the UK.
With the UK Government pursuing a carbon neutral environment, it is imperative that every action is taken to reduce energy consumption. Rooflights are energy efficient as they let in large amounts of natural light thus reducing the need for artificial lighting.
With so many choices available, choosing the right conservation rooflight can be a bit of a minefield but with the right guidance and advice it need not be a stressful experience.
[edit] Related articles on Designing Buildings Wiki
IHBC NewsBlog
‘Local Heritage Listing: Identifying and Conserving Local Heritage’ Published
Historic England has published a new edition of its advice note on how local heritage listing and local heritage lists can be formally identified as part of the wider range of designation so that they can be taken into account in planning applications.
Hammersmith Bridge illuminated red in Valentine’s Day message to Government
The stunt aimed at highlighting ongoing delays to its repair, as the 133-year-old west London bridge has been closed to traffic since April 2019 when cracks appeared in its pedestals.
Drone Surveying a London Landmark
Uninhabited Aerial Vehicles (UAVs) have been used to undertake a survey of the Lloyd’s building’s external façade in the heart of the City of London.
Green Party calls for no VAT on refurbishment in new Parliamentary petition
The petition calls on the government to remove VAT on refurbishment projects and raise VAT on non-Passivhaus new-build construction to 20 per cent. Retrofitting is carbon-efficient but the current VAT regime privileges new build over refurbishment.
Conservation Professionals Concerned about Future Planning Policy
Directors of the IHBC and the Victorian Society are among those whose opinions are featured in the RICS in-house publication Modus as it explores heritage impacts in England’s planning proposals.
Learn all about the Professions in Building Conservation at upcoming Conference
Glasgow City Heritage Trust (GCHT) 3-day online conference aimed at anyone working, or interested in working, within the building and heritage sectors.
New use for abandoned oil rigs: Offshore reefs!
One way in which these old rigs can be remarkably useful is that the subsurface rig can provide the ideal skeleton for coral reefs, allowing the remarkable ecosystems beneath the waves come into their own.
Birnbeck Pier, in Weston-super-Mare, to undergo Restoration
A new company – Birnbeck Holdings Limited – has now been set up by CNM Estates which has purchased Birnbeck Island and the historic pier.
Ecclesiastical Heritage Risk Barometer 2020 Published
The publication offers research to help answer the question: ‘How can the heritage sector adapt and thrive in the digital age’?
Victorian Bath House dug up from under a Manchester Car Park
A stunning Victorian Bath House has been uncovered during works on creating the city’s first public park in over 100 years.