How To Measure For a Roof Lantern


Roof lanterns are a fantastic addition to any home, offering not just practical benefits like increased natural light and ventilation, but also adding a touch of architectural elegance; however, to ensure a perfect fit and seamless installation, precise measurements are essential. 

In this comprehensive guide, we’ll take you through the step-by-step process of measuring for a roof lantern, covering everything from basic dimensions to considering structural elements and regulations. 

What you need to measure for a roof lantern 

Before you start measuring, make sure you have the following tools within reach: 

Tape measure 

A good quality tape measure is essential for accurate measurements. 


Depending on the height of your roof, you may need a ladder to access the area safely. 

Pencil & Paper 

Keep these handy for jotting down the measurements, as well as any notes you may want to take along the way. 

How to measure for a roof lantern 

To measure for a roof lantern, you’ll need to do the following: 

Measuring the roof opening 

Start by measuring the width and length of the roof opening from the inside. Measure at least three times to ensure accuracy, as even small discrepancies can lead to problems later on. 

Note down the largest measurement to ensure the roof lantern will fit comfortably. 

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Accounting for roof pitch and angle 

Next, consider the pitch or angle of your roof. This will affect the size and shape of the roof lantern. 

Measure the angle accurately using a level or protractor, as this information is crucial for ordering the correct size and ensuring a seamless fit. 

Measuring external kerb dimensions 

Measure the external kerb dimensions, taking into account any protrusions or obstructions that may affect the placement of the roof lantern. It’s essential to measure both the width and depth of the kerb to ensure the roof lantern sits flush and securely. 

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Allow for frame and structural support 

Factor in the frame and structural support of the roof lantern. Consider the thickness of the frame and any additional supports required for installation. Make sure there is enough space around the roof opening to accommodate these elements without compromising the structural integrity of your roof. 

Leave space for installation 

Ensure there is ample space around the roof opening for installation. Proper ventilation is crucial to prevent condensation and maintain optimal indoor air quality. Leave enough room for air to circulate freely around the roof lantern, especially if it’s located in a kitchen or bathroom. 

Roof lantern measuring best practices 

When it comes to measuring your roof lantern, don’t forget to follow these best practices: 

Measure twice for accuracy 

Double-check all measurements to ensure accuracy. It’s better to spend a little extra time measuring than to encounter problems during installation due to incorrect dimensions, such as roof lantern leakage

Consult with roof lantern experts 

If you’re unsure about any aspect of the measuring process, don’t hesitate to consult roof lantern experts. They can provide valuable guidance and recommendations based on their expertise. 

Get Perfectly-Fitted Roof Lanterns with GFD Homes 

At GFD Homes, we’re all about delivering top-notch, custom-fitted roof lanterns. Our team of experts is here to walk you through the measuring process, ensuring every dimension needed is just right for your project. With our support you’ll seamlessly incorporate our roof lanterns into your space, inviting in the beauty of natural light to elevate your home ambiance. 

So, whether you’re looking for contemporary roof lanterns, traditional roof lanterns or even slimline roof lanterns, know that we’ve got you covered every step of the way. 

For more information on roof lanterns, feel free to visit our website or check out our blog

FAQs about roof lantern measuring 

What is the minimum upstand for a roof lantern? 

The minimum upstand requirement varies depending on the type and size of the roof lantern. 

Generally, a minimum upstand of 150mm is recommended for flat roofs to ensure proper drainage and weatherproofing; however, for pitched roofs, the upstand may need to be higher to accommodate the angle of the roof and prevent roof lantern leakage. 

Are there any specific regulations or building codes to consider when measuring for a roof lantern? 

Yes, there may be regulations and building codes governing the installation of roof lanterns, especially concerning structural integrity and energy efficiency. Always check with local authorities first to ensure compliance. 

Additionally, consider any roof lantern planning permission requirements, especially if you live in a conservation area or your property is listed. 

How do you measure outdoor roof lanterns? 

Measuring outdoor roof lanterns follows a similar process to indoor ones, with added considerations for weatherproofing and exposure to the elements. Be sure to account for these factors when taking measurements and consider opting for materials and finishes that are durable and weather-resistant.  

By following these guidelines and best practices, you can ensure a seamless and successful roof lantern installation, bringing natural light and beauty into your home for years to come. 

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Tia Ellahi
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