VELUX Installer Replacement Guide

 VELUX Installer Replacement Guide

There's a quiet opportunity sitting above the heads of millions of homeowners.

A generation of VELUX roof windows, installed during the housing boom of the 1980s and 90s, is reaching the end of its natural life. Frames are weathering. Energy performance has degraded over time. And homeowners? They're ready to upgrade - they just need you to show them how straightforward it is.

The replacement opportunity has never been bigger.

Here's everything you need to know to make the most of it.

For Installers: Fast, clean, profitable jobs

This is where it gets compelling for your business. Because VELUX has maintained consistent roof window sizing for decades, most replacements are a straight, same-day swap - no reworking the roof, no major internal alterations.

 

 

In most cases, a replacement job can be completed in under 4 hours, entirely from inside the home.

 

That means:

• Minimal disruption for the homeowner
• No need for scaffolding (in most cases)
• Clean, efficient jobs that protect your reputation
• More jobs completed per week

Identifying the roof window: Understanding VELUX generations

Before you specify, you need to identify what's already in the roof. The data plate on the existing roof window is your starting point - it tells you the roof window type, size code, glazing type, and production code (which reveals the age and origin of the unit).

Here's a quick guide to VELUX generations:

Generation

Notes

VKI

Pre-1992

Installed 27mm further out of the roof - EL/EW replacement flashing

VES

1992–2001

Installed 27mm further out of the roof - EL/EW replacement flashing

V21

2001–2014

Standard flashing

V22

2014–present

Standard flashing

 

 

One important exception: There's no modern like-for-like replacement for the GGL-5. The closest option is an FK06, which is 40mm narrower. Use the EL/EW 6000F flashing (which includes insulation foam) to bridge the gap neatly between the new window and the existing roof timbers.

Minor adjustment note: When replacing sizes GGL 102, 104, or 206, minor plasterboard adjustments will be required.

Choosing the right flashing:

Getting the flashing right is critical - and it comes down to one question: how old is the existing roof window?

Replacing a window installed before 2001?

Choose an EL or EW replacement flashing. These are specifically designed so that the new roof window sits directly onto the existing internal lining, with no internal alterations required. The new roof window slots in, the brackets supplied with the flashing do their job, and the job is done cleanly.

• EL flashing — for slate roofs up to 8mm thick
• EW flashing — for profiled roofing material up to 120mm

 

Both come in two versions:

• 1000 — includes underfelt collar
• 6000F — includes underfelt collar and insulation

 

Replacing a window installed after 2001?

Use a standard flashing. Suitable for newer roof windows, same professional result.

The Upsell conversation: Turn a replacement into an upgrade

A replacement job is the perfect moment to have an honest conversation about what's possible. Most homeowners don't realise they can upgrade at the same time, within the same roof opening.

 

Here's what to mention:

Upgrade the finish

Old timber frames can be replaced with a white maintenance-free (PU) finish - the most durable and robust finish available, and completely maintenance-free.

Upgrade the operation

For roof windows that are hard to reach, solar operation is the logical upgrade. No electrician required, no wiring to run - the roof window is powered by the sun (and still works on cloudy days).

Upgrade the glazing

For homeowners near busy roads, under flight paths, or simply after better thermal performance, triple glazing is a compelling option. Better insulation, meaningful noise reduction, and future-proofed energy performance.

Complete the look with blinds and shutters

No transformation is complete without accessories. VELUX blinds and external shutters are manufactured specifically for each roof window, so they fit perfectly and install quickly. They also significantly increase the value of the job.

The key is making sure homeowners know what's possible before you start the job - not after. A short conversation upfront can transform a straightforward swap into a premium installation they'll talk about for years.

Take it further: The VELUX Partner Programme

If you're doing VELUX replacement work - or want to do more of it - the VELUX Partner Programme is worth signing up for.

Get access to exclusive training courses (including in-depth replacement training), VELUX Rewards, and the support to grow this side of your business confidently.

Find out more and sign up at velux.co.uk/partner or velux.ie/partner

The replacement opportunity is out there. Homeowners are ready. The jobs are fast, the margin is strong, and the opportunity is only getting bigger. Now's the time to make the most of it.