Add Natural Light and Space with a Roof Window Loft Conversion
A roof window loft conversion (often called a Velux or rooflight conversion) uses existing roof slopes, inserting high quality windows to flood your loft with natural light and ventilation. Because you don’t need to change the shape or structure of the roof, this style of conversion tends to be less disruptive, faster and more affordable than dormer or extension options.
Why Choose a Roof-Window / Velux Loft Conversion?
Minimal structural changes: There’s no outward roof extension, so your roofline remains intact — a key benefit of Velux conversions.
Cost-effective: They are often the most affordable loft conversion option, given the lower amount of structural alteration needed. Simply Loft lists starting costs from £28,000 + VAT depending on window count and layout.
Quick build time: Many Velux conversions complete in 3–5 weeks (some sources say 4–7 weeks depending on complexity) because less structural work is required.
Great natural light & ventilation: Roof windows transform dark lofts into bright, airy spaces. Some systems include automatic opening, blackout blinds, or rain sensors.
Permitted development eligibility: In many cases, you won’t need full planning permission. Because you’re not expanding the roof externally, the conversion often falls under permitted development rights (though there are conditions).
What You Can Expect from Our Service
With O'Sullivan Lofts, your roof window conversion is handled from A to Z:
Specification & installation of premium roof windows (Velux® or similar)
Insulation, electrical, plumbing (if needed), and internal finishes
Building regulations approvals and compliance
Full project management and quality assurance
Benefits That Go Beyond Light
Makes your loft into usable living space (bedroom, office, studio)
Increases your property’s value
Improves thermal efficiency and comfort
Minimal disruption to the home structure
Clean external aesthetic — no bulky extensions
Why Homeowners Choose Us
We’re committed to delivering beautiful, functional, hassle-free loft conversions. Our experienced team focuses on quality, clear communication, and finishing to a high standard.
Frequently Asked Questions About Roof-Window Conversions
Do I need planning permission for a Velux/roof-window conversion?
Most times, no, these conversions typically qualify under permitted development rights, since they do not alter the roofline. However, properties in conservation areas, listed buildings, or other restricted zones might need full planning. We manage all checks and submissions for you.
How long will it take to build?
Usually between 3 and 5 weeks, depending on design complexity, finishes, and structural details.
What’s the cost?
We typically see conversions starting at £28,000 + VAT, though final costs depend on window number, layout, insulation, and finishes.
Can I have multiple windows?
Yes, you can install several roof windows to maximise light and airflow. The exact layout depends on your roof slope, structure, and how much light you want. We offer a wide range of roof window options from leading brands such as Velux® and Keylite, including:
Standard Velux® and Keylite roof windows for daytime light and fresh air.
Top-hung roof windows for easy opening and panoramic views.
Electric or solar-powered roof windows for remote or automatic operation.
Blackout roof windows—ideal for bedrooms and spaces where you need complete darkness.
Moisture-resistant roof windows—perfect for bathrooms or humid spaces.
Combination windows—continuous rows or multiple windows for maximum daylight.
During your free survey, we’ll recommend the best number, placement, and type of Velux® or Keylite roof windows to match your loft’s design and your preferences.
Will the conversion match my existing design?
Absolutely. We match window styles, interior finishes, and ensure the overall look complements your home.
Ready to bring daylight and life to your loft? Contact us to arrange a free, no-obligation survey & quote. See how a roof-window conversion can transform your space.
Looking for more space and full-height rooms? Check out our dormer-loft-conversion Flat Roof Dormer Loft Conversions. A stylish way to maximise your loft’s usable space.
