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Flat Roof vs Pitched Roof Skylight Extensions

Rooflight on pitched roof

When looking at building an extension, it is important to understand the whole picture before you make any decisions. The choice between flat rooflights and pitched rooflights can significantly impact the ambiance and functionality of your living space. Each type offers distinct advantages and drawbacks worth considering.

What is a flat rooflight?

A flat rooflight is designed for flat roofs. They’re often used in contemporary buildings to maximise natural light into open-plan living spaces. Flat rooflights are typically modern, sleek and aesthetically pleasing. Some common areas for rooflights are kitchens, living rooms and extensions. 

What is a pitched rooflight?

Pitched rooflights fit seamlessly into pitched or sloped roofs. Pitched rooflights are typically constructed with the angle of a roof in mind to ensure they blend in with the exterior of a building. Similar to flat rooflights, pitched rooflights are usually installed to maximise the amount of light let into a room. They are commonly found in attic conversions, barn conversions, lofts, and buildings with vaulted ceilings.  

What’s the difference between a flat roof and pitched roof skylight extensions?

If you’re considering installing a rooflight, realising the advantages of flat or pitched options is essential to make sure you understand the value you’re adding to your home.

Roof slope

Sloped roofs usually require a pitched rooflight, enabling higher ceilings and better drainage of both water and snow. When installing a rooflight on a flat roof you’ll get a modern aesthetic and a crystal clear view of the sky. You may already have a flat or sloped roof that is suitable for a rooflight. The slope of a pitched roof is around 15-70 degrees, while a flat roof is around 10-12 degrees.

Construction and materials

The construction and materials of rooflights depends on if they’re being installed in a flat or pitched roof. Flat rooflights typically utilise reinforced glass and aluminium frames; however, pitched rooflights typically tempered glass, and stainless steel, with wooden or PVC frames.

We offer a variety of pitched and flat rooflights of the highest quality at Toughened Glass Systems. 

Benefits of pitched roof skylight extensions

Pitched roof skylight extensions are a popular choice for homeowners that enhance any living space, they reduce the need for artificial lighting, add ventilation in some cases and blend in with multiple architectural styles.

Higher ceiling

High or vaulted ceilings have been desirable for years. They create a spacious and airy atmosphere in a room providing depth and elevated style. Having a pitched roof ensures ample headroom and comfort, as well as lending themselves to the latest open-plan living trends.

Increased natural light

The need for natural light is being emphasised even more by modern architecture, a pitched roof skylight is the perfect way to maximise a room’s natural light intake. Pitched skylights are installed at an angle, which in turn maximises the amount of sunlight let into a room throughout the day.

Design benefits

Pitched rooflights can enhance the visual aspect of any home, elevating a room to a whole new level. Pitched skylights come in various styles, from opening rooflights to living rooms. They’re even suitable for bathrooms. This allows for you to pick a rooflight that seamlessly blends into your home. The majority of pitched rooflights open to allow airflow into a room and heat to escape in summer.


At Toughened Glass Systems all of our pitched roof skylights are designed with durability in mind to ensure they can withstand rain, snow and wind, keeping your home warm, while costing you less.

Low maintenance

If you choose a pitched roof skylight you’re likely to do less maintenance than when you pick a flat roof skylight, providing you with peace of mind for years to come. Adequately installing them and cleaning them semi-regularly will ensure they last a long time. 

Drawbacks of pitched roof skylight extensions

Installing pitched roof skylights offer a lot of benefit. However, there are some drawbacks to consider before building your extension or installing a pitched roof skylight.


Pitched skylights or rooflights tend to be more expensive compared to other skylights. The bulk of that cost comes from the construction and installation which could increase the cost of your extension considerably.

Less options

When you compare pitched roof skylights to flat roof skylights, there are less options available in terms of design. Pitched roof skylights are limited to the pitch of the roof and space available, whereas flat roof skylights allow for more choice for homeowners. 

Requires more construction

Installing pitched roof skylights require more labour than other options. They can require more extensive modification to a roof to ensure proper installation and longevity. 

Limited suitability

Certain houses or extensions may not be ideal candidates for a pitched roof skylight. Roofs with specific configurations, such as hip roofs or those with angles less than 15 degrees, typically aren’t compatible with pitched roof lights.

Benefits of flat roof skylight extensions

Flat roof skylight extensions offer several advantages over pitched roof skylights that make them a popular choice for a lot of homeowners. 

More affordable

Flat roof skylights tend to be more affordable than other types of skylights like pitched or pyramid skylights. Their simple but elegant design makes them easier to install, bringing their cost down even lower than before. 

Modern design

Flat roof skylight extensions typically come in a range of sleek, contemporary designs that compliment most, if not all, modern architecture styles. Their minimalist style allows for an additional touch of style to any home. 

More options

Flat roof skylight extensions provide homeowners with a wide range of options in terms of size, shape, and placement. Their flexibility allows for more customisation to suit individual homeowner preferences to suit your property.


Flat roof skylight extensions are versatile and can be used with various roof types and architectural styles. That includes homes, businesses, or extensions. They blend seamlessly with the existing structure, offering flexibility in design and functionality.

Drawbacks of flat roof skylight extensions

While flat roof skylights have great benefits, there are some disadvantages to them too. You should consider the following things:

More prone to damage

Flat roof skylights are great, but they are more prone to damage from accumulation of debris, snow, or water. The flat surface allows pooling of water which could eventually cause leaks or structural damage; however, they are easier to clean than pitched roof skylights. 

Buying your flat rooflight from a trusted company like Toughened Glass Systems will ensure your product is durable.

Requires more regular maintenance

These types of features require more regular maintenance due to their design when comparing them to other types of rooflight. Regular cleaning and inspection are necessary with flat roof lights to ensure proper drainage, to prevent build-up and preemptively find any issues

Less durable

When compared to pitched roof skylights, flat roof skylights tend to be less durable, especially when exposed to harsher weather conditions. The materials used in flat roof skylights slightly differ from the ones used in pitched skylights, which means they deteriorate slightly faster.

Again, buying from a reputable rooflight company is essential.

What factors will affect the cost of a rooflight extension?

Home renovation projects require a lot of planning and consideration depending on the extent of the extension. There are multiple things to consider such as size, the number of windows, installation costs, architectural fees (If you’re doing a larger extension), local authority costs and structural work. 

Ensuring thorough planning and assessment of these factors can contribute to a smoother and more cost-effective rooflight extension project.

How much does it cost to convert a flat roof to pitched UK?

Undertaking a home renovation project can be difficult, and requires a lot of consideration before you take the plunge. When planned properly, a full extension can not only go smoothly, but also be cost effective. Here are some factors you’ll need to consider in the cost of getting a roof conversion done:

  • Choice of materials
  • Labour
  • Extension size
  • Extension dimensions
  • Additional expenses for rooflights, windows or doors
  • Installation of plumbing, electrical, and gas
  • Current condition of the space
  • Architectural fees and drawings
  • Extra costs for lighting, flooring, and decoration

Considering a rooflight extension or conversion for your home? Discover our selection of pitched roof skylight windows, flat roof skylights, and conservation roof lights tailored for heritage buildings. Contact our team today to learn more about our offerings and how we can assist you with your project.

Choose Toughened Glass Systems for quality skylights

When it comes to selecting skylights for your home, opting for Toughened Glass Systems ensures the highest quality skylights. At Toughened Glass we offer a large range of pitched roof and flat roof skylights making us the perfect choice for your purchase. We also offer a wider selection of rooflights and skylights, including:

Contact us today to find out more.

More helpful articles


How often does a flat roof need to be replaced in the UK?

The lifespan of a flat roof varies depending on factors such as maintenance, weather conditions, and more. Typically, a flat roof may need replacement every 15-30 years. However, with prompt problem-solving and regular maintenance, its longevity can be extended. For a more precise estimation that’s specific to your property, consulting with a building industry expert is advisable.

Do I need planning permission to change a flat roof to a pitched roof?

When converting a flat roof to a pitched roof in the UK may come under permitted development rights; however, you should always check with your local authority and review regulations in your area.

Some factors that may affect your properties permitted development rights and planning permission could be the size and height of the new, pitched roof, the neighbouring properties and your conservation area, if applicable.

Based on 210 reviews
Bob toploft
Bob toploft
I am the owner of Top loft company ltd, after reviewing reviews from various companies I ordered 2 juliet balconies from tgs arrived within 3 weeks, comunications and help was brilliant. Thanks for all your help.
Jim H
Jim H
Great service from the team. Easy to order, good buying guidance and clear install instructions for my builder. Rooflights look absolutely great! The team at TGS couldn't have been more helpful in organising a smaller delivery vehicle to help with restricted access. Highly recommend TGS.
Jack Smith
Jack Smith
Great service from a very knowledgeable company. Thanks team Toughened Glass Systems.
Paul Smith
Paul Smith
I was spending a lot of money on several rooflights so I wanted to make sure I got it right and I did. The professionalism, expertise and the quality of the roof lanterns really set Toughened Glass Systems apart.
Tyrone Eldridge
Tyrone Eldridge
There are no complaints about the experience with TGS. The entire process of ordering, supplying and delivering was flawless. I would really recommend you order your flat roof sky lanterns from these guys.
Robert Childers
Robert Childers
Best place for rooflights, they supply many different types and options. Thanks for all your support Toughened Glass Systems!
John Smith
John Smith
The glass balustrade gives us an amazing view onto the lake outside. So happy we ended up going for the frameless glass balcony from Toughened Glass Systems instead of one with posts
Louise Newsome
Louise Newsome
My job is to design the interiors for a lot of houses and a lot of times the hardest part was when the client wanted some really inexpensive rooflights that should look like some contemporary ones as well. That until I found Toughened Glass Systems and started working with them more and more. They have a lot of this kind of stuff at a very decent price, a price for anyone I can say. If you’re looking for cheap skylights for flat roofs or any types of roof lights, they probably have something for you.
Krystina Taylor
Krystina Taylor
Always kept us up to date with our order even when delayed by a few days. Great service from the start and good quality glass balcony delivered.