Flat-roof skylights: are specifiers walking on precarious glass?

Despite the serious risks associated with sub-standard products, there are currently no mandatory standards in place to regulate the manufacture and sale of flat-roof skylights in the UK. Justin Seldis, Managing Director at leading provider Sunsquare, explains what this means for specifiers – and what they can do to help make a change.



s an impressive way to bring natural light, air and access to buildings, flat-roof skylights are becoming increasingly common in architectural projects across the UK. The market is following suit, with sales steadily on the up and more products than ever becoming available for specification.

But, while this is excellent news for architects looking for more choice and competitive pricing, it’s come at a cost. The stark reality is that the flat-roof skylight industry as it stands is entirely unregulated. The result? Specifiers and end-users are walking on precarious glass, and it’s only a matter of time before the cracks turn into breaks.

The story so far: a self-governing industry

At the moment, there are no mandatory safety, quality or efficiency standards governing the manufacture or supply of flat-roof skylights in the UK. The Construction Products Regulation (305/2011/EU) stipulates that CE Marking is a legal requirement for certain types of glass to be sold on the UK market, but it doesn’t cover the completely assembled product.

There are rules and regulations pertaining to ‘in-plane’ rooflights – or those made from GRP or plastic – but no harmonised European standard for out-of-plane flat-roof skylights. When it comes to installation and performance, Building Regulations (specifically Parts K and L) provide some guidance, but it’s not a given that products will comply (and the regs themselves only come into play later in the specification process).

In the absence of any official guidelines, manufacturers have a duty of care to adhere to standards of their own. However, not everyone has the same outlook on what this means – and in the world of flat-roof skylights, we’re definitely seeing a sliding scale of responsibility.

How are manufacturers responding?

At best, the current situation has prompted individual manufacturers to implement their own product-specific quality assurance methods. The most popular option is to seek bespoke third-party verification of certain claims, from organisations like the BBA (British Board of Agrément) and the BRE (Buildings Research Institute).

This kind of testing helps provide customers with some peace of mind, but what it doesn’t do is provide an industry-wide benchmark to help architects compare one product against another. For this, what we need to see is a uniform set of standards applying to all flat-roof skylights on the market.

Quality assurance leader the BSI (British Standards Institution) has developed a BSI Kitemark accreditation specifically for flat-roof skylights, created to provide a brand agnostic comparison framework and internationally-recognised stamp of quality. However, it’s yet to become commonplace across the industry. In fact, at the time of writing, Sunsquare products were the only flat-roof skylights on the market to hold a BSI Kitemark.

At its worst, the lack of regulation in our industry has enabled some rogue (and frankly, dangerous) products to come to market. In a bid to produce skylights faster, cheaper and at larger volumes, there have been cases of manufacturers using it as a loophole to cut corners; supplying stock that simply doesn’t make the grade for quality, efficiency or safety.

A question of quality

From an operational perspective, the core design considerations of flat-roof skylights are air permeability, weathertightness and wind resistance. In the absence of any independent certification, architects could be specifying products that have an impressive look (and price tag) but fail to perform even at the most basic level. Very simply, they’re leaky, flimsy and they won’t stand up against the weather when it matters most.

Even if they’re well-designed, in a market where independent testing isn’t a must-have, the use of quality components isn’t guaranteed. Whether it’s replacing sturdy aluminium frames with wooden upstands or compromising on glass strength to save on costs, cheaply made (often imported) products are providing a false economy, and simply aren’t delivering the durability customers need in their homes and businesses.

Troubling thermal performance

Another area that’s been left up to interpretation by the lack of blanket rooflight standards is U-values. At the moment, many manufacturers are getting away with understating these (by focusing on the performance of the glass alone) or misreporting them by incorrectly adding up the U-values of each individual skylight component to provide a whole-system score.

They’re also using the term ‘thermally managed’ to gloss over the fact that a rooflight isn’t fully protected against thermal bridging of cold air from outside its metal frame to the glass inside. Only thermally broken products (which feature in-frame insulating sections or ‘breaks’ to conductivity) are equipped to provide an effective barrier between internal and external temperatures – anything less is just marketing jargon!

A skylight with overstated thermal performance ultimately means a colder building, more condensation, higher heating bills and a larger carbon footprint. It could also mean a failure to meet Part L altogether.

Safeguarding customers

The biggest concern about unregulated rooflights is the risk they pose to our (and our children’s) safety. Substandard products are literally hanging above our heads in our homes, workplaces and public spaces. They are yet to undergo any independent safety testing – and from rooflights incorporating exposed glass edges that are vulnerable to breakage, right through to the use of unlaminated glass that won’t stay put if it shatters, there’s plenty of room for error.

What’s next?

Until such times as legal regulation is put in place, the onus is on manufacturers to set the standards (and adhere to them). For this, the industry needs cohesion; the only way specifiers and consumers can fairly and confidently choose the right rooflight for their projects is if we’re all using the same quality assurance criteria.

Because of this, at Sunsquare we’d like to see all flat-roof skylight manufacturers adopting BSI Kitemark accreditation – proving that their whole product (rather than just the glass) has been tested to destruction to ensure ultimate durability and performance. This would also provide customers with complete peace of mind about the safety, security and thermal properties of their skylights.

However, architects also have their own part to play. Specifiers hold the key to the future of the market, and with this in mind, they have the power to demand their flat-roof skylights are independently tested, and meet only the very highest quality, safety and efficiency criteria. After all, where there is demand, the market will soon follow.

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