Why Do I Need a Roof Lantern Upstand?

If you’re planning to install a roof lantern as part of a new extension, flat roof renovation, or home improvement project, you’ve probably come across the term “upstand.” But what exactly is it, and why is it so important?

In this blog, we’ll break down what a roof lantern upstand is, its role in ensuring a successful installation, and why every roof lantern needs an upstand.

What Is a Roof Lantern Upstand?

An upstand is the raised frame or kerb that sits on the flat roof and supports the roof lantern. Think of it as the base or foundation for the roof lantern to be securely fitted. It raises the rooflight above the surface of the roof to:

• Provide a weathertight seal
• Improve drainage
• Comply with building regulations
• Ensure thermal performance

While some roof lanterns are supplied with an integrated upstand, many are not, and the installer (or builder) must create one on-site, usually with timber or other weatherproofed materials.

1. It Ensures a Weatherproof Seal

One of the most important reasons for having a roof lantern upstand is to protect your property from water ingress.

Flat roofs are particularly vulnerable to standing water and poor drainage. A properly constructed upstand elevates the roof lantern above the level of the finished roof surface, helping to:

• Direct water away from the glazed unit
• Prevent pooling or leaking around the base
• Ensure a tight and secure seal with the roofing membrane

Without an upstand, the roof lantern would sit flush with the roof, a big no-no in wet climates like the UK’s. The upstand acts as a first line of defence against leaks.

2. It Provides a Strong, Stable Base

Roof lanterns can be heavy, especially larger designs made from aluminium and double or triple glazing. An upstand ensures there’s a solid, level base to support the structure safely.

Whether you’re installing a lantern for the first time or replacing an old unit, a well-constructed upstand:

• Distributes the weight evenly across the roof structure
• Ensures the lantern is level (even if the roof isn’t)
• Prevents flexing, cracking, or long-term movement

Skipping the upstand could compromise the integrity of the roof, or worse, lead to future failures in the glazing system.

3. It’s Required to Meet Building Regulations

Installing a roof lantern without a properly designed and insulated upstand could lead to:

• Non-compliance with Building Control
• Failed inspections
• Voided product warranties

For peace of mind and full compliance, always include a compliant upstand in your planning and installation.

4. It Helps with Thermal Performance

Modern roof lanterns are designed to offer excellent thermal insulation, helping homeowners reduce heat loss and improve energy efficiency.

But the upstand plays a key role in supporting that performance. A well-insulated upstand:

• Reduces thermal bridging (cold spots around the lantern perimeter)
• Prevents condensation build-up inside the room
• Helps maintain airtightness

Timber upstands should be insulated with rigid foam or similar materials.

In short: to get the full thermal benefit of your roof lantern, a properly insulated upstand is essential.

5. It Allows for Proper Drainage

Flat roofs may not appear to slope, but they usually have a slight pitch to allow rainwater to drain effectively. Installing a roof lantern flush with the roof surface could lead to water pooling around the edges, increasing the risk of leaks.

By raising the unit above the roof line, the upstand:

• Encourages effective water runoff
• Prevents standing water around the frame
• Helps extend the life of the roof and glazing

For this reason, most roofing guidelines recommend a minimum upstand height of 150mm above the finished roof surface.

6. It Supports a Cleaner, Neater Installation

From a practical and aesthetic point of view, an upstand gives the installer a clean frame to work with, making it easier to:

• Align the roof lantern precisely
• Seal and weatherproof around the base
• Finish off internal plasterboard and trims neatly

Especially in high-spec or minimalist interiors, a good upstand can make the difference between a professional-looking installation and a rushed one.

Some installers even pre-clad the upstand with matching materials to create a flush, modern finish inside and out.

7. It Offers Design Flexibility

When you have control over the upstand’s size and angle, you can influence the final look and performance of the roof lantern installation. For example:

• A taller upstand can increase the perceived depth of the lantern from inside the room
• A slightly sloped or chamfered upstand can help reduce water retention on certain roof types
• A bespoke upstand allows for non-standard roof lantern sizes or shapes

Working with an experienced installer or specifying a prefabricated upstand can give you greater control over both performance and appearance.

Final Thoughts

If you take one thing away from this blog, let it be this: a roof lantern upstand isn’t optional, it’s essential.

Whether it’s built on-site or supplied with the product, the upstand:

• Protects your home from water damage
• Improves energy efficiency
• Ensures a strong, safe installation
• Keeps your project compliant with regulations

It might not be the most glamorous part of the installation, but it’s one of the most important. Don’t overlook it, plan for it, build it right, and your roof lantern will reward you with years of light, comfort, and peace of mind.

At UK Rooflights we offer our upstands on our roof lanterns as an optional extra, to allow for added installation and energy efficiency. Interested in finding out more? Speak to our team on info@ukrooflights.co.uk today!