The Ulitmate Guide to Installing a Rooflight in Your Home

guide to installing a rooflight installation extras. installing a rooflight in a pitched roof

We want to make installing your rooflight as simple as possible. To do this we have created this comprehensive guide to installing a rooflight. If you have any questions along the way please do not hesitate to call us!


Flat Glass Rooflight

Confirm which size rooflight best suits your needs.
It is recommended that you purchase the rooflight
before you start work on your roof. At Hitech there
are 12 sizes available.

create a 5 degree angle when fitting a rooflight

The rooflight must incorporate a minimum 5° pitch. If your existing roof lacks this pitch, you will need to install the kerb/upstand to ensure this minimum 5° pitch is achieved. This angle is crucial for effective water drainage, preventing water accumulation on the glass surface.

create the opening in the roof when fitting a rooflight

Preparation of the Roof Opening: Begin by measuring and accurately marking the precise location for the rooflight installation. Make certain that the opening dimensions match the specifications of the roof light you’ve acquired. For example, if you’ve purchased a 1000×2000 rooflight, the hole you cut in your roof should match these dimensions exactly. Additionally, it is essential to thoroughly clear any debris from the area to ensure a clean and smooth surface.

build a kerb or upstand when fitting a rooflight

After installing the opening, start to construct or install the timber kerb. Ideally, the recommended upstand height should be 150mm above the level of your roof covering, as per the guidelines outlined in the BS 6229:1982 code of practice for flat roofs. Additionally, ensure a minimum pitch of 5° or a 100mm incline for every 1000mm of roof length for optimal performance.

provide a roof membrane when fitting a rooflight

Apply Roof Covering: When applying your chosen roof covering, whether it’s GRP, EPDM, or any other material, it’s imperative that the covering extends up and over the kerb, completely enveloping the top of the kerb. Ensure that this surface is as flat and free of lumps as possible. This meticulous approach is crucial for establishing a watertight seal once the rooflight is installed.

seal the glass to the kerb when fitting a rooflight

Installing the Glass Pane: Begin by applying a generous silicone seal along all four surfaces of the kerb. Don’t be overly concerned about the appearance of the seal; the key is to create a robust, watertight connection between the glass and the kerb. Next, apply a second seal to the rebated part of the kerb, focusing on the inner panes. Ensure the glass is correctly aligned and evenly seated within the kerb.

Provide a silicone seal when fitting a rooflight

Seal the Edges: To further enhance weatherproofing, apply a compatible silicone sealant around the perimeter of the glass pane where it meets the kerb/upstand and smooth off. It’s crucial to select a sealant that matches the materials used in both the rooflight and the roof surface.

test for leaks when installing a rooflight

Testing for Leaks: After the rooflight has been installed and sealed, it’s vital to conduct a thorough leak test. Simulate rainfall by using a hose or water source and meticulously examine the interior for any indications of water infiltration. If you detect any leaks, take immediate action by resealing or adjusting the installation as needed.

guide to installing a rooflight installation extras. installing a rooflight in a pitched roof

Adhere to Maintenance Guidelines:
Consistent cleaning and routine inspections are essential for preventing debris accumulation and identifying any necessary maintenance requirements.

It’s worth noting that the installation process can vary based on the specific kerb or upstand utilized. Therefore, it’s imperative to thoroughly review and adhere to the provided installation manual for a secure and successful installation. If you have any uncertainties about a particular step or lack the requisite skills, we strongly recommend consulting a professional installer or a contractor with expertise in rooflight installations.

Please be aware that if you haven’t used our dedicated kerb, you’ll need to install a timber internal frame to support the weight of the inner two glass panes. Refer to the images on the next page for guidance.

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