Velux window installation guide can completely transform a dull, dark attic or loft into a bright, airy, and comfortable living space. Velux windows are known for their premium quality, energy efficiency, and stylish design. Whether you want to create a cosy bedroom, an inspiring workspace, or just bring natural sunlight into your home, learning how to install a Velux window yourself can be both satisfying and cost-effective.
This is specially written for beginners who want to understand every step of the installation process. You’ll learn about the tools you need, the safety precautions and a detailed step-by-step method to help you install your Velux window like a professional roofer.
What is a Velux Window?
A Velux window is a type of roof window designed for pitched roofs. Unlike regular windows, it’s installed directly into the roof slope, allowing daylight and fresh air to flow freely into attic rooms or loft conversions. Velux windows are built with precision, using high-quality materials like laminated glass and weatherproof frames.
They come in various sizes and designs — manual, electric, and even solar-powered versions — to fit different roofing structures. Velux has become a trusted brand worldwide due to its durability, energy efficiency, and easy-to-install system.
Why Install a Velux Window?
There are many benefits to adding a Velux window to your home:
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More Natural Light:
Roof windows allow up to twice as much natural light compared to traditional vertical windows. This brightens up dark rooms and creates a warm, inviting atmosphere. -
Improved Ventilation:
Velux windows can be opened to let fresh air circulate, keeping your indoor environment healthy and comfortable. -
Energy Efficiency:
The glass used in Velux windows helps maintain indoor temperature, reducing energy bills during winter and summer. -
Increased Property Value:
Adding a Velux window enhances the appearance and functionality of your home, which can increase its resale value. -
Aesthetic Appeal:
These windows look elegant both inside and outside, giving your home a modern architectural touch.
Before You Start Important Preparations
Before you begin cutting into your roof, a few important preparations will make your project smooth and safe.
1. Safety First
Always work with proper safety gear. You’ll need gloves, safety goggles, a helmet, and non-slip footwear. Avoid working in bad weather — rain or strong winds can make the roof slippery and dangerous.
2. Check Local Building Regulations
Depending on your location, you may need planning permission to install a new roof window. Always check with your local building authority before starting work.
3. Choose the Right Size and Model
Velux offers many sizes and designs, so choose one that suits your roof type and room size. If you’re unsure, measure the distance between your rafters and check the product specifications before purchasing.
4. Gather All Tools and Materials
Make sure you have everything ready before climbing onto the roof.
Step-by-Step Velux Window Installation Process
1. Mark the Position
From inside your loft, decide where the window will go. Use a measuring tape and pencil to mark the exact area between the roof rafters. Ideally, choose a position where the window will receive plenty of sunlight and fit naturally within the structure.
Once you’ve chosen the spot, drill small guide holes in each corner of your marked area — this will help you identify the correct position when you move onto the roof.
2. Prepare the Roof Opening
On the outside, remove the roof tiles or slates covering the marked area. Cut through the roofing felt carefully to expose the rafters. Next, use a saw to cut the battens and create the rough opening.
Make sure the opening matches your window’s measurements. Always double-check the size — it’s easier to remove a bit more later than to fix an oversized hole.
3. Fit Support Beams (Trimmers)
To create a strong frame for your window, you’ll need to install horizontal trimmer beams at the top and bottom of the opening. These beams support the weight of the Velux window.
Use screws and brackets to secure them firmly. Always ensure they are level and square. Use your spirit level to check this — if the frame isn’t straight, the window may not open or close properly.
4. Install the Window Frame
Now, it’s time to fit the Velux window frame. Velux windows come with special installation brackets. Fix these brackets to the window frame before lifting it into the roof opening.
With help from another person, lift the frame into place. Check it with your spirit level to ensure it’s perfectly horizontal and vertical. Secure the frame with screws into the side rafters.
Once the frame is fixed, test that it’s firm and aligned before moving on.
5. Fit the Flashing Kit
The flashing kit is what keeps your window waterproof. It’s one of the most important steps in the installation process. The flashing ensures that rainwater runs around the window instead of seeping through it.
Velux offers flashing kits designed for different roof materials like slate, tile, or metal. Always choose the right one for your roof type.
Start from the bottom flashing and work upward, overlapping each section to direct water away from the window. Make sure every piece fits tightly and neatly.
6. Replace Roof Tiles
After installing the flashing, you can start placing your roof tiles or slates back around the window frame. Cut the tiles if needed to fit neatly against the flashing edges. This will give your roof a clean and professional finish.
7. Fit the Window Sash
Next, it’s time to install the sash — the part that opens. Velux makes this step easy. Lift the sash into the frame and click it onto the hinges. Test the opening and closing to make sure it operates smoothly.
If it feels tight or uneven, slightly adjust the screws until it moves freely. This ensures long-term comfort and usability.
8. Insulate the Frame
Insulation is crucial for energy efficiency. Use suitable insulation material (like foam or mineral wool) to fill any gaps between the window frame and roof. This step prevents heat loss and condensation.
Once insulation is complete, you can move on to interior finishing.
9. Finish the Interior
Inside your loft or room, finish the window surround with plasterboard or wood panels. Shape and smooth the edges for a neat appearance. Once done, you can paint or decorate the area to match your interior design.
This not only improves the overall look but also seals the window for maximum comfort and durability.
10. Final Inspection
Once everything is in place, check your installation thoroughly. Open and close the window several times. Look for any gaps or uneven edges. Pour a small amount of water on the exterior to ensure there are no leaks.
If water runs off smoothly without entering the frame, your installation is successful!
Maintenance Tips for Longevity
Velux windows require very little maintenance, but regular care keeps them looking and working like new.
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Clean the glass with mild soap and a soft cloth every few months.
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Inspect flashing and seals for cracks or wear once a year.
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Lubricate hinges to keep the mechanism smooth.
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Remove debris like leaves and branches from around the window.
Following these tips will help your window last for decades.
Common Mistakes to Avoid
Even small errors during installation can lead to leaks or misalignment. Here are a few things to watch out for:
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Not using the correct flashing kit for your roof type.
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Forgetting to level the window frame properly.
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Skipping insulation around the window edges.
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Working without proper safety precautions.
Take your time at each step — precision and patience are key to a perfect result.
Conclusion
Installing a Velux window yourself might seem like a big task, but with the right guidance, it’s absolutely achievable for beginners. It’s a fantastic way to improve your home’s lighting, ventilation, and value.
By following this Velux Window Installation Guide, you’ve learned how to plan, measure, cut, fit, and finish a professional-quality Velux window installation. Once complete, you’ll enjoy the warmth of natural sunlight, the comfort of fresh air, and the satisfaction of having done it yourself.