Skylights: Choosing, Buying and Installing (2022)




What is a skylight?

A Skylight is a roof window that is designed to make optimum use of natural daylight, providing a natural light source.

Skylights can also be known as roof lights, roof windows, Sunpipes, Roof Lanterns, Skypods and Roofdomes. There are small differences between them, however, they all share the same main purpose of providing a natural light source from the roof rather than from the wall.


What is a lantern skylight?

A roof lantern skylight, also known as a Roof Lantern is a pitched skylight that’s ideal for bringing a light and airy feel to a room. Roof lanterns allow natural daylight in to create a spacious atmosphere, bringing the outside in. They differ from a normal roof light, which is usually flat and made up of a single pane of glass, polycarbonate or acrylic. Instead, roof lanterns are pitched and made up of multiple panels.

TBS Polycarbonates’ Roof Lanterns are bespoke and made to measure with a 7-10 working day lead time, available in white, black ash, anthracite grey, rosewood and golden oak finishes with a range of glazing options.


What are hipped rooflights?

Hipped rooflights are often confused with roof lanterns because hipped rooflights are essentially roof lanterns with “hips”, which means there is a small section of the rooflight at the very bottom that goes vertically up before it starts to slope to form a pitched rooflight. The reasons for this include the aesthetic appeal and improved structural integrity.


What are flat glass rooflights?

A flat glass rooflight is simply one flat glass or plastic panel that is designed to be installed on a flat roof. The appeal of flat glass roof windows over roof lanterns is that the frame is only on the outside of the window, therefore, you can’t see the frame from the inside, just clear window. Some people find this to be more aesthetically pleasing than being able to see the frame of a roof lantern. This design is also more suitable for more modern looking houses where a lantern rooflight may look too traditional or not in keeping with the modern style of the house.


What are dome rooflights?

Roofdomes or dome rooflights are hipped rooflights with a dome-shaped glass or plastic panel. Dome rooflights can provide up to three times more daylight through a flat roof than a similarly sized window in a vertical plane. TBS Polycarbonates have over 40 sizes available from stock at competitive prices with next day nationwide delivery available for most sizes.


an Dome on the roof


What are skylights made out of?

In the past, most skylights have been made from aluminium. These are not only expensive, but the ‘industrial’ design isn’t to everyone’s taste. That’s why we created Skypod. As well as offering outstanding looks, it costs less and provides the perfect match for your existing PVC-U windows and doors. There is even a choice of 5 different frame colours:

  • White Skypod
  • Golden Oak Skypod
  • Rosewood Skypod
  • Moondust Grey Skypod
  • Anthracite Grey Skypod

Skylight glazing is usually made from plastic or glass. Plastic glazing costs less and is stronger than glass. You also have the option of using UV protected hard coated polycarbonate roof glazing such as Plasiax Diamond, which features a 2 sided abrasion resistant hard coating providing protection against abrasion, chemicals, graffiti abuse, and UV issues. Plasiax Diamond is incredibly strong and impact resistant (10x that of glass), lightweight (half the weight of glass), heat resistant, recyclable, and easy to fabricate.

Cast Acrylic glazing can also be used with skylights, featuring exceptional light transmission higher than that of glass, excellent resistance to weathering and discolouration, excellent properties for fabrication and polishing, and it’s recyclable.

Extruded acrylic glazing also boasts outstanding resistance to weathering, excellent thermoforming capabilities (making it ideal for applications where complex shapes are required), and good optical clarity. It’s hard wearing, easily fabricated, and has a high gloss finish.


Which glazing material is best for skylights?

To help glaziers decide which material to use for rooflights, here is a summary of the attributes of Polycarbonate, Acrylic and Glass.


  • TBS Polycarbonates recommended choice
  • Virtually unbreakable
  • Highest fire rating available
  • Certified ‘Non-Fragile’ (when used in conjunction with our Plasiax Wire glazing system)


  • Economical
  • Good UV resistance
  • ‘Fragile’
  • Care must be taken when specifying due to lack of fire rating


  • Resistant to discolouration and degradation
  • Scratch resistant
  • ‘Fragile’
  • Heavy, making it impractical to transport


Skylights and planning permission

According to Planning Portal, approval under the Building Regulations will generally be needed for the installation of a new rooflight because the structure will need to be altered, the roof will need to carry the load of the new rooflight, the rooflight will need sufficient insulation, and if it is close to a boundary the fire protection will need to be considered.


How do you install a skylight in a commercial building?

Roof windows should be installed by a trained professional, and they must always consult the manufacturer’s guidelines. Commercial buildings typically have flat roofs because they are much more cost-effective than pitched roofs.

Check out this video by Eurocell to learn how to install a Skypod Roof Lantern:

According to even the most energy-efficient skylight must be properly installed to ensure that it achieves its energy performance, so it’s vital roof windows are installed by a professional and to the manufacturer’s guidelines.


How much do skylights cost in the UK?

Skylights can cost anywhere between £100 to £2500 or more depending on the size, type and materials. A basic roof window will cost around £80 to £1000, dome rooflights will cost around £100 to £2000, and roof lanterns/skypods will cost £1000 to £2500 or more. TBS Polycarbonates Skypod skylights are a cost-effective alternative to Aluminium Skylights, which can be quite expensive.

TBS Polycarbonates provides accurate quotations that meet your exact requirements.




How many years do skylights last?

TBS Polycarbonates Skypod skylights are guaranteed for ten years, so you can be sure that you’re buying a robust, well-designed, precision-made product that’s built to last. Other systems like our flat glass rooflights also come with a 10-year guarantee.


How much does it cost to replace skylights?

It depends on the type and size of the skylight, however including the cost of the window and labour you can expect to be spending upwards of £1000. You should consider refurbishment first, check out Glazing Face’s glazing refurbishment service.


Do skylights leak?

Unfortunately, skylights have a reputation for leaking. This reputation was earned by old techniques, old designs and incorrect installation of roof flashing. Modern skylights correctly installed by a professional should not have any more risk of leaking than a regular window, the problem of skylights leaking no longer exists.


What are the common problems with Skypods and Roofdomes?

Common problems might include:

  • Size – Sometimes Roofdomes and rooflights already made are hard to fit into existing roof structures.
  • Roofdomes fade in the sun as they are plastic and they can break easier over time too.
  • Hail, wind, snow and debris can damage a roofdome or roof lantern.
  • Poor installation can lead to moisture ingress or condensation.


Questions TBS Polycarbonates are frequently asked about Skypods and Roofdomes



Are they in stock?

No, they are made to order.

Can they be made to size?

Yes, we even have ways of doing modular cassette type installations where multiple domes or rooflights are put together.

Do domes break?

Double skin polycarbonate domes are strong and able to withstand considerable impact.

What colours do they come in?

Typically the framework on the roof lanterns come in anthracite grey or white, however, we are able to get these coloured to whatever your specification is.

Are they expensive?

It depends what specification the glass is and how large the rooflight is. The most cost saving is in installation, roof lanterns are made in the factory and dry fitted together so they only need fixing down and bolting together.

How quickly can I get one?

Some of our range is available the next day, the Skypods can be as quick as 5-7 working days and other products in the range take from 1-2 weeks.


What tips/advice can you give about Skypods and Roofdomes?

The most important thing is to make sure you know where you are measuring to and from when requesting a quote and placing an order. Also, make sure the roof is strong enough to take the weight of any glass and make sure there are no major trees overhanging where the lantern will be.

You should consider if the roof is accessible, make sure you have a safe area to work from and wear the appropriate PPE. You should also consider if someone is likely to have to tread on the roof window, if yes you will need walk-on specification.


Where can I buy skylights in the UK?

TBS Polycarbonates are a UK based supplier of Skylights and stock a fantastic range of Roof lanterns, Skypods and Dome Rooflights with quick lead times, bespoke designs and fast delivery.

You can order online for nationwide delivery or visit our modern trade counter in Cheshunt. If you have any questions you can email, phone 01992 622 823 or fill in the online enquiry form.

This article was written by William Gresswell.

William started at TBS in 2008 after leaving upper sixth form working in fabrication and cutting, he started on the trade counter and has worked through to business development. William actually worked part-time at TBS during holidays from a young age until he officially started full-time. William has completed a 2-year advanced business management course, a course with the chartered institute of management accountants (CIMA) and holds City and Guild certificates in basic electrics, plumbing, brickwork and carpentry.


Connect with William on LinkedIn!

TBS polycarbonate skylight

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  1. Jay Jorgenson

    My mom wants to save money on energy. I like how you explain that a Skylight is a roof window that is designed to make provide natural light. Thank you for the information. I’ll recommend her to purchase a skylight and have a professional install it.

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