When you decide to buy tailored glass rooflights, you are not simply purchasing a product - you are making a long-term investment in how your home looks and feels. Off-the-shelf rooflights have their place, but for homeowners with extensions, kitchen rear additions, garden rooms, or loft conversions on flat roofs, a tailored solution almost always delivers a better result. When you buy tailored glass rooflights, you get a unit built precisely for your opening, your glazing preferences, and your thermal requirements with no compromise on fit or finish.
This guide walks you through everything you need to know before placing your order, from sizing and glazing types through to installation and planning considerations.
Why Tailored Glass Rooflights Outperform Standard Sizes?
Standard rooflight sizes work well on straightforward projects where the opening has been designed around the product. Most domestic extensions are not built that way. Structural openings are determined by loadbearing walls, RSJ positions, and roof build-ups - not by the nearest stock rooflight dimension.
The result, when homeowners choose a standard unit, is often a rooflight that is slightly too small for the opening, requiring infill boxing that reduces the glazed area and the amount of daylight entering the room. A tailored glass rooflight eliminates this problem entirely. The unit is manufactured to the exact dimensions of your upstand or kerb, meaning the maximum possible glass area floods the space below with natural light.
Beyond sizing, tailored rooflights allow you to specify exactly the frame finish, glazing type, and opening mechanism that suits your home - rather than accepting whatever a standard range offers.
Tailored Rooflights by Room Type: What Works Best
|
Room / Use |
Recommended Glazing |
Key Feature to Prioritise |
|
Kitchen extension |
Double or triple glazed |
Solar control coating to reduce glare |
|
Garden room / orangery |
Triple glazed |
Low U-value for year-round comfort |
|
Bedroom loft extension |
Double glazed, obscure option |
Privacy glass or blackout blind compatibility |
|
Utility / boot room |
Double glazed |
Self-cleaning glass for low maintenance |
|
Open-plan living space |
Triple glazed |
Large format sizing, solar control |
|
Home office |
Double or triple glazed |
Anti-glare, self-cleaning coating |
Fixed vs Opening: Which Type Do You Need?
Fixed Flat Glass Rooflights
Fixed units are the most popular choice for domestic installations. They are simpler in construction, lower in price, and when correctly specified - provide excellent daylighting with no mechanical components to maintain. Our fixed flat glass rooflights are available in bespoke sizes with double or triple glazing and a range of frame finishes.
For rooms that are well-ventilated through windows or doors, a fixed rooflight is almost always sufficient.
Opening Flat Roof Skylights
Where the room below has limited alternative ventilation, an opening rooflight is worth considering. Electrically operated units with rain sensors are a popular choice - they can be left open during the day and will close automatically if rain is detected. This is particularly useful on kitchen extensions where cooking produces moisture that needs to escape.
Explore our range of opening flat roof skylights for electrically operated options in custom sizes.
Sizing Your Rooflight Correctly: A Practical Guide
Getting the size right before you order is the single most important step in the buying process. Here is how to approach it:
Measure your upstand internally. The rooflight sits on top of the upstand or kerb, so the dimension you need is the internal measurement of the upstand - not the structural opening size.
Allow for the frame overlap. Most aluminium framed rooflights overlap the upstand by a standard amount. Check the product specification so you can account for this when placing your order.
Consider the room below. As a general guide, a rooflight should cover roughly 15–20% of the floor area of the room below to achieve a well-lit space without overheating. For a 20 square metre kitchen extension, that means a minimum of 3–4 square metres of glazing.
If you are uncertain about sizing, our team at Skylights Roof Lanterns is on hand to help. Visit our contact page and share your measurements for a no-obligation recommendation.
Ready to Buy Tailored Glass Rooflights?
A well-specified, made-to-measure rooflight transforms a flat-roof extension from a functional space into a genuinely light-filled room. Whether you are finishing a kitchen addition, a home office, or a full-width rear extension, buying a tailored unit rather than a standard size is almost always the right decision.
Browse our full range of custom flat glass rooflights at Skylights Roof Lanterns - with UK delivery in 1–3 working days on selected products, competitive pricing, and expert support from our team throughout the process.
