AJR Roofing — Sheffield & South Yorkshire
Velux Window Installation in Sheffield: What to Expect from Start to Finish
A Velux roof window can make a real difference to a loft, bedroom, or bathroom — bringing in natural light and improving ventilation in rooms that often feel dark or stuffy. But for a Velux window to work well and stay weatherproof, the installation needs to be done properly. This guide explains what Velux window installation involves, how to choose the right window for your roof, and what to watch out for to avoid leaks.
If you are looking for a Velux window installer in Sheffield or South Yorkshire, contact AJR Roofing for a free, no-obligation quote or call 07852 940350.
- Velux windows can be fitted to most pitched roofs with the right flashing kit
- Installation typically takes one day for a single window on a straightforward roof
- The flashing kit is critical — it must match the roofing material to prevent leaks
- You usually do not need planning permission for a standard Velux in an existing roof slope
- Velux windows should be installed by an experienced roofer to maintain weather integrity
- Poorly fitted flashings are the most common cause of Velux-related leaks
- AJR Roofing installs Velux windows across Sheffield and South Yorkshire
Why People Choose Velux Windows
Velux is the market-leading brand for roof windows and skylights. When people say “Velux window,” they often mean any roof window — but Velux as a brand is known for quality, reliability, and a wide range of sizes and glazing options.
The main reasons homeowners in Sheffield get Velux windows installed include:
- Loft conversions — adding windows to a new loft room to bring in natural light
- Dark bedrooms or bathrooms — rooms that face north or are overshadowed benefit significantly from roof light
- Ventilation — opening Velux windows helps with air circulation, particularly useful in warm weather or in rooms prone to condensation
- Replacing existing old roof lights — older roof windows can become drafty, leaky, or difficult to operate and benefit from modern replacements
Types of Velux Roof Window
Velux offer several different types of window. The right choice depends on where it will be positioned and how you want it to open.
The most common type. The sash pivots at the centre, so the top half swings inward when opened. Easy to clean from inside. Suits most roof slopes and positions.
Opens from the bottom, with the hinge at the top. Provides a clear view when open and is popular in rooms where you want an unobstructed sightline. Slightly better for ventilation.
A glazed skylight that lets in light but does not open. Good for areas where ventilation is not needed, or where opening access would be difficult. Often used in stairwells or landings.
Motorised Velux windows open and close via a remote control or wall switch, with some models offering rain sensors that close automatically. Useful for high or hard-to-reach positions.
Velux also offer roof windows designed specifically for flat or very low-pitched roofs, using a different flashing and dome system. These are worth considering for garage extensions or outbuilding roof lights.
What Velux Window Installation Involves
A professional Velux installation is more involved than fitting a standard window. Here is a step-by-step overview of what happens during a typical job.
Step 1 — Choosing the right size and position
Before anything is ordered, the roofer will check the roof structure, the rafter spacing, and the available wall height inside the room. Velux windows come in a range of standard sizes. Ideally the window fits between existing rafters without cutting structural timbers, but it is sometimes necessary to cut and reframe around a new window — this adds time and skill to the job.
Position matters too. A window placed too close to the ridge or to the eaves can cause problems with water shedding and weather-tightness. An experienced roofer will advise on the best location.
Step 2 — Selecting the correct flashing kit
The flashing kit is the most important part of the installation from a weatherproofing point of view. Velux produce different flashing kits depending on the roof covering: plain tiles, slates, profiled tiles, and different pitch ranges all require a specific kit. Using the wrong flashing kit, or a generic alternative, is one of the most common causes of Velux leaks.
An experienced roofer will specify the correct Velux flashing kit for your roof type and pitch.
Step 3 — Cutting the opening
The appropriate tiles or slates are removed, the roof membrane is cut carefully, and the opening is formed. If rafters need to be trimmed or reframed, this work is carried out at this stage. The opening is kept as weatherproof as possible throughout.
Step 4 — Fitting the window frame and flashing
The Velux frame is secured to the roof structure, then the flashing is fitted around it layer by layer — working from the bottom up, just as with any waterproofing detail. Tiles are refitted around the window, cutting to fit where necessary, and lead or metal flashing soakers are positioned to shed water away from the frame.
Step 5 — Internal finish
Once the external work is done, the interior reveal is typically lined with plasterboard or a Velux lining kit to create a clean finish inside the room. This can be done by the roofer or left for a plasterer/joiner if preferred — your installer will discuss this with you.
Do You Need Planning Permission for a Velux Window?
In most cases, installing a Velux window in an existing roof slope does not require planning permission in England. Under permitted development rights, roof windows are generally allowed provided they do not project more than 150mm beyond the roof plane and the top of the window is no higher than the existing ridge.
There are exceptions. If your property is in a conservation area, is a listed building, or has had its permitted development rights removed (this can happen on some newer estates), you may need to apply for planning consent before work starts. Your roofer can advise, but it is always worth checking with Sheffield City Council if you are unsure.
How to Avoid Velux Leaks
A well-installed Velux window should not leak. When leaks do occur, they almost always come down to installation errors rather than product defects. The most common causes are:
- Wrong flashing kit — the flashing must match the tile type and roof pitch exactly
- Flashing installed in the wrong order — each layer must be fitted in sequence, working from low to high, for correct water shedding
- Gaps at the side or head flashings — small gaps allow wind-driven rain to enter at the sides or top of the frame
- Roof membrane not lapped correctly — the underlay or roofing membrane beneath the tiles needs to be cut and sealed around the frame carefully
- Condensation mistaken for a leak — occasionally what looks like a leak is actually condensation forming on the glass or frame, which can happen in poorly ventilated rooms
Choosing an experienced roofer who works with Velux regularly is the most reliable way to get a leak-free installation.
Replacing an Existing Roof Window
If you already have a roof window that is leaking, difficult to open, or simply old and draughty, replacing it is often straightforward. Velux produce replacement windows designed to fit into existing frames, which can reduce installation time significantly. Your roofer will measure the existing frame and advise whether a direct replacement or a new installation is the better option.
Common Questions About Velux Installation
How long does Velux installation take?
A single Velux window on a standard pitched roof typically takes one day, including removing tiles, fitting the frame and flashing, and reinstating the tiles. Additional windows, or roofs that require structural reframing, will take longer.
Can Velux windows be fitted to any roof pitch?
Velux windows can be fitted to roofs with a pitch between approximately 15° and 90°. For very low pitches, a different product range is needed. Your installer will confirm whether your roof pitch is suitable before work is planned.
Do Velux windows need maintenance?
The windows themselves are low-maintenance, but it is worth checking the external flashings every few years, particularly after heavy storms or if you have seen any minor drips. Keeping the drainage channels clear of leaves and debris helps too.
Will a Velux window make my room significantly warmer or colder?
Modern double-glazed Velux windows have good thermal performance. Rooms with Velux windows do gain more solar heat gain in summer and can feel warmer than rooms without. Blinds (available directly from Velux) help to manage this. In winter, a well-fitted modern Velux should not noticeably increase heat loss compared to a standard double-glazed window.
AJR Roofing — Velux Window Installers in Sheffield
AJR Roofing installs Velux roof windows for homeowners and landlords across Sheffield and the wider South Yorkshire area. We handle everything from sizing and ordering to fitting, flashing, and the internal finish — and we will give you honest advice on position, specification, and planning requirements before any work starts.
To find out more about what we do, visit our Velux windows service page. For roof repairs of any kind, see our roof repairs page. You can also view where we work across Sheffield and South Yorkshire.
AJR Roofing — Sheffield & South Yorkshire. Call 07852 940350 | ajrroofing17@gmail.com | Contact us