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What is a Skylight Upstand?

Upstands are crucial for skylight installations, elevating them above the roof to ensure proper water runoff and weather protection. This essential design feature prevents leaks and structural damage by ensuring a secure, weather-resistant junction between the skylight and the roof.

Skylights, are a great way to bring light and ventilation into our homes, not only elevate the beauty of a room but also offer significant benefits like energy savings and enhanced well-being. However, a crucial element often overlooked in achieving a successful skylight installation is the skylight upstand. This article explores the critical role, structure, and design considerations of skylight upstands.

Upstands are essential in ensuring skylights integrate flawlessly and function at their best. Acting as raised frames, they provide the necessary elevation and slope for the skylight above the roof, offering protection against the elements while maintaining the structural integrity of both the skylight and the roof.

Why do I need an upstand for my skylight?

An upstand for your skylight isn’t merely a building requirement; it serves as a cornerstone, enhancing the skylight’s functionality, safety, and energy efficiency.

Part L Building Regulations

Under the latest regulations, specific U-value standards have been established for skylight upstands, ensuring they meet rigorous energy efficiency criteria. When constructing an upstand on-site, it must achieve a maximum U-value of 0.35W/(m²·K) to comply with these standards. Conversely, if the upstand is provided as part of the skylight system, the combined or system U-value must not exceed 2.2 for existing dwellings. These measures are designed to enhance thermal performance and energy efficiency in homes.


The point where the skylight meets the roof is vulnerable to water ingress. Upstands offer essential protection by raising the skylight above the roof surface, preventing water accumulation and maintaining a watertight seal. Materials like EPDM, felt, fiberglass, or specialized weatherproofing kits are commonly used for this purpose, creating a membrane that extends up the side of the upstand, forming a tray to safeguard your home from leaks and moisture issues.

Energy Efficiency

The thermal performance of upstands, often overlooked, is now addressed in the latest building regulations. It’s crucial for upstands to meet these regulations to maintain your home’s thermal envelope. Additionally, ensuring airtightness is essential, as the seal between the skylight and the upstand can be a significant source of heat loss.

We offer a variety of upstands to suit different needs, including a 60mm option for the Flex (upstand U value of 0.71 W/m²K) and a 75mm option for the EOS75 (upstand U value of 0.54 W/m²K). However, our premium EOS97 skylights truly shine with impressive double glazed system U-Values as low as 0.97 W/m²K. Equipped with our 97mm wide insulated upstands, they achieve an industry-leading system U-value of 0.66 W/m²K with triple glazing. What’s more, our upstands alone boast an exceptional U-Value of 0.39 W/m²K, surpassing many competitors and ensuring unparalleled energy efficiency that exceeds Approved Document L standards.

EOS97 open with aluminum cladding for builders upstand

Structural Integrity

When installing a skylight, whether you are building a new roof or creating an opening in an existing roof’s structure, an upstand serves as a crucial element, offering essential support and stability. It ensures the roof can effectively bear the weight of the skylight, preserving the building’s safety and durability.

Upstand Pitch

The pitch or slope of the skylight is a critical consideration, especially for flat glass installations. Skylights with a shallow pitch risk water pooling on the glass, leading to maintenance issues. While the minimum pitch requirement is 5 degrees, opting for a slightly steeper pitch of 5 degrees ensures optimal performance and efficient water runoff.

In the case of lantern skylights, upstands need to be flat, protruding a minimum of 150mm on all sides, as they are not susceptible to water pooling. We offer both flat and pitched (5 degrees) options to accommodate your specific requirement.

Read more about the importance of a upstand pitch here.

Upstand Height

Building regulations stipulate a minimum height of 150mm for upstands to provide adequate weather protection. It’s crucial to ensure compliance with this requirement for approval by your building inspector. In some cases, you may need to increase the height of your upstand, commonly seen in warm roofs. In warm roof constructions, where insulation buildup reaches around 150mm, the upstand may not meet the required height from the roof deck. To maintain both thermal efficiency and weatherproofing, the upstand height should be increased to approximately 300mm in such cases.

Tall upstand to allow for warm roof built up insulation

Why Choose an EOS Rooflights Upstand?

At EOS, our upstand is a cornerstone of manufacturing process, seamlessly integrating with our skylights. Constructed from structural insulated boards featuring a foam core, our upstands are precision-cut using our CNC machine to ensure exacting precision for every project. Continuously innovating, we now offer an integrated motor option for the EOS97 opening skylight. With three different width options available for flat or 5-degree pitches, and heights of 150mm or 300mm to suit your specific requirements. Delivered flat-packed or ready made with clear instructions our upstands are designed for effortless quick installation, making them a preferred choice among builders, roofers or even self builders.

Insulated upstand - timber with pitch for warm or cold roofs
Upgrade your warm roof with our versatile upstands!

Achieve exceptional insulation performance, easy installation, and long-lasting reliability. Explore our range of upstands and elevate the performance of your warm roof today!

Contact our team

If you have any questions, would like a bespoke price or want to enquire about our installation service. Give us a call or drop an email:

Call EOS Rooflights today 0208 462 3557

Eamil EOS Rooflights Today [email protected]

4.83 Average

315 Reviews


Easy to deal with, the pricing was great and delivery of 5 skylights was quick and stress free. One small problem was quickly resolved, great company.

Posted 5 months ago

Justin David Davis

Great product despatched and delivered very quickly

Posted 5 months ago


Great rooflights

Posted 5 months ago


Recently purchased an electric roof light from EOS. Very happy with the finished product, study and functions very well. It also looks very stylish. I received excellent customer service from EOS at all stages, they couldn't have been more helpful. Highly recommended.

Posted 6 months ago


Great Rooflights , simple to fit and swift delivery, many Thanks

Posted 7 months ago

Liam Grenander

Very professional customer support / sales team. Dealt with our roof light enquiry quickly and kept me updated on transit and delivery. Will be purchasing roof lights from them again when our projects require them.

Posted 7 months ago

Brad Lander - Bailand Construction Ltd

EOS Rooflights were knowledgable in their field, very helpful and the products (Roof Lantern and Flat glass roof lights) were of a good quality. The Roof lights were easily installed and full installation instructions were supplied for those who are installing for the first time. Would recommend.

Posted 7 months ago

A Memet

Very efficient with processing my order and delivery. I ordered a 3M roof lantern and a smaller flat roof light. Both were simple to install on my own upstands and they both look great. My only negative was the cost was a lot for what they are but I don’t think eos are excessively expensive, I think the roof lanterns themselves are what’s pricey. Anyhow I’m happy 😃

Posted 10 months ago


EOS were brilliant all through the consultation/sales process and delivery. The skylight looks great and works a treat with the electronic switch. Their after-care support was also very helpful and patient when we mistakenly thought we had an issue. Would highly recommend them.

Posted 11 months ago

Jonathan Tregidga Buyer at Legacy

As a company we have used EOS for some time. We use the EOS Rooflight Flexi Lid product a lot and also the EOS Smoke Vent Rooflight AOV on our projects. We cannot fault the company for the service, communication and value for money.

Posted 1 year ago


Excellent products, great customer service and post sales support! Unfortunately the courier damaged our roof lights slightly, however EOS went above and beyond to rectify! Special mention to Natalie O’Hara in ops, she was so helpful, prompt and a real pleasure to deal with! Highly recommend EOS!

Posted 1 year ago


Great delivery, great product. Really helpful customer service to organise the delivery of the rooflight

Posted 1 year ago


My Eos rooflight turned up on time as always, simple to install and looks great, throws so much light into what was a dark space, the quality of the rooflight is amazing, I will continue buying from Eos in the future,

Posted 1 year ago

Clive Woodford

The rooflights are a key feature externally of the property as they are prominent on the flat roof. They are angled by 15 degrees to allow the south facing sun to enter the house maximising natural light and also utilising any solar gain. The majority are triple glazed, with a couple of larger opening lights being double glazed. Internally they provide so much light and the light shafts are a characteristic of the internal architecture given that there are 15 within the house. The ordering and supply process was straightforward and installing them worked well with the pre-made upstands. All in all a very satisfactory and successful decision to select Eos rooflights.

Posted 1 year ago

Mr Jones

I was after rooflights with laminated glass and of good quality! I contacted EOS after seeing and viewing their products. They fitted the requirements. The service was first rate, nothing was a problem and the drawings to work before delivery excellent. Would highly recommend.

Posted 1 year ago

Matt Wilson

Great quality rooflight, delivery was as planned and on time. We will be using this company again.

Posted 1 year ago

Dave R

Professional and friendly throughout. Delivery was prompt and product is great.

Posted 1 year ago

Mr J Tregidga Buyer (Legacy Construction)

As always the service was excellent. Item was installed and gave us the finish that we expected and is a quality product to go with our quality development. EOS never seem to deliver on quality and in service

Posted 1 year ago

Chris Law

Most importantly, a brilliant product - we are absolutely delighted. On top of that, great customer service and excellent price.

Posted 1 year ago


Great communication and customer service. Lovely staff, all willing to help. Delivery was swift and hassle free. Awesome rooflight. Great feature to our ongoing project. If I needed another rooflight, I would definitely use EOS again.

Posted 1 year ago


Excellent customer service and advice and top quality product. Thank you

Posted 1 year ago