Skylight Replacement Cost: Repair, Reseal or Replace?
Skylight replacement in the UK typically costs £1,000 to £3,500 fitted, depending on size, glazing and access. Smaller jobs cost much less. Resealing a skylight usually costs £50 to £150, a flashing or frame repair £175 to £400 and new glass £250 to £850. The right option depends on the condition of the glass and frame.
This guide breaks down the cost of each option, from a simple reseal to a full replacement. It covers product prices by size, labour, extras and the factors that shape a roofer's quote. It is written for UK homeowners comparing quotes for a flat roof skylight.
How Much Does Skylight Replacement Cost in the UK?
A full skylight replacement typically costs £1,000 to £3,500, based on MyBuilder's cost guide. BestBuilders' 2026 guide puts a fixed flat rooflight at £1,200 to £2,600 fitted. That figure includes labour, flashing, internal finishing and making good.
Size has the biggest effect on the total. A small 600x900mm unit on a single-storey extension usually comes in at the lower end. A large 1000x2000mm skylight on a first-floor roof is more likely to reach the upper end, especially with scaffolding.
Glazing also plays a part. Double glazing suits most homes. Triple glazing adds to the product price in exchange for better heat retention and sound reduction.
How Much Does a Replacement Skylight Cost to Buy?
The skylight itself is often a smaller share of the total than homeowners expect. At Rooflights and Skylights UK, a frameless fixed flat rooflight starts at £165 ex VAT for a 500x500mm unit. A 1000x1000mm frameless unit is £420 ex VAT. A 1000x2000mm unit is £650 ex VAT.
Framed models cost a little more. A framed 1000x1000mm rooflight is £585 ex VAT. The largest framed size, 1000x3000mm, is £1,282 ex VAT. Custom sizes start from £373.33 ex VAT for frameless and £503.33 ex VAT for framed.
Buying direct from a UK manufacturer keeps the product price clear before any roofer visits. Every unit comes with a 10-year guarantee. Standard sizes ship in 3 to 4 working days, with custom sizes in 7 to 10 working days. The flat roof skylights collection shows every size with its price.
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Explore Rooflight Collection →How Much Does It Cost to Reseal or Repair a Skylight?
Resealing is the lowest-cost option. MyBuilder puts it at £50 to £150. A reseal replaces worn sealant around the frame and usually takes a few hours. Regular seasonal skylight maintenance helps the new seal last longer.
Flashing or frame repairs cost more, typically £175 to £400. Flashing is the material that seals the joint between the skylight and the roof. Renewing worn flashing is one of the most common repairs on an older unit.
Replacing just the glass costs around £250 to £850. This option suits a skylight with a sound frame and a misted or cracked glazed unit. The guide to skylight repair vs replacement explains the signs that point to each choice.
What Do Roofers Charge for Skylight Labour?
MyBuilder lists roofers at £30 to £50 an hour and glaziers at £30 to £55 an hour. Most repairs take a day or less. A like-for-like replacement into an existing kerb is often a one-day job for an experienced roofer.
Labour rises when the kerb needs work. A new kerb, a change in opening size or extra roof repairs around the old unit can add a second day on site.
Choosing a replacement in the same size as the existing opening keeps labour down. Measuring the inside of the kerb before ordering helps match the new unit to the opening.
What Extra Costs Affect a Skylight Replacement Quote?
Scaffolding is the largest extra. BestBuilders puts it at £600 to £1,200, depending on roof height and access. On single-storey extensions, roofers can often reach the skylight with a ladder or tower instead.
Building Regulations also apply. The Planning Portal states that replacing a rooflight needs Building Regulations approval. A roofer registered with a competent person scheme can usually self-certify the work. Otherwise, a Building Control application typically costs £200 to £300 in England and Wales.
Some roofers list disposal of the old unit and making good inside the room as separate lines on a quote. Asking for an itemised quote makes it easier to compare roofers fairly. The right questions to ask before hiring a rooflight installer help compare experience as well as price.
When Is Replacing a Skylight Better Value Than Repair?
A reseal at £50 to £150 makes sense for a skylight with clear glass and a sound frame. A full replacement offers better value when the glass is misted, the frame is worn or repairs keep coming back.
An older single-glazed or polycarbonate dome is also a strong candidate for replacement. A modern double-glazed frameless rooflight reaches a U-value of 1.0 W/m²K. That brings more daylight and better heat retention. Over time, this can help with heating bills.
Skylight Repair and Replacement Costs Compared
|
Option |
Typical Cost |
|
Reseal |
£50 to £150 |
|
Flashing or frame repair |
£175 to £400 |
|
Glass replacement |
£250 to £850 |
|
Replacement flat rooflight, product only |
£165 to £1,282 ex VAT |
|
Full replacement, fitted |
£1,000 to £3,500 |
|
Scaffolding, if needed |
£600 to £1,200 |
Frequently Asked Questions
- How much does it cost to replace a flat roof skylight?
- Is it cheaper to reseal or replace a skylight?
- How long does it take to replace a skylight?
- Does a skylight replacement need Building Regulations?
- How much does it cost to repair a leaking skylight?
- Can the glass in a skylight be replaced on its own?
- How long does a flat roof skylight last?
- Does replacing a skylight need planning permission?
A full flat roof skylight replacement typically costs £1,000 to £3,500 fitted in the UK. The product itself starts from £165 ex VAT for a 500x500mm frameless unit. Size, glazing, kerb work and access make the biggest difference to the final price.
Resealing is much cheaper, at around £50 to £150. It works well for a skylight with clear glass and a sound frame. A unit with misted glass or a worn frame usually needs new glass or a full replacement.
A like-for-like replacement into an existing kerb usually takes about a day. Jobs that need a new kerb or roof repairs around the opening can take two days.
Yes. The Planning Portal states that replacing a rooflight needs Building Regulations approval. A roofer registered with a competent person scheme can usually self-certify the work.
MyBuilder puts the cost of repairing a leaking skylight at £150 to £850. The final price depends on how severe the leak is and whether the flashing also needs attention.
Yes, provided the frame is in sound condition. MyBuilder puts glass replacement at £250 to £850. Where the damage is extensive, a full replacement can offer better value.
Many manufacturers design rooflights to last around 30 years with proper care. Regular cleaning and seasonal checks of the seals and flashing help a skylight reach that lifespan. Every flat rooflight from Rooflights and Skylights UK comes with a 10-year guarantee.
A replacement skylight does not normally need planning permission when it projects no more than 150mm beyond the roof plane and stays below the highest part of the roof. Owners of listed buildings or homes in conservation areas should check with the local planning authority first.