Replacing a skylight

If your skylight is getting old or leaky, it might be time for a replacement! Read our guide on how to replace a skylight, as well as tips on when it’s likely to need replacing and how to choose a new one.

Want to skip ahead? Go to instructions on how to replace a skylight.

Ready to view options? Explore our range of skylights (for unoccupied rooms) and roof windows (for occupied rooms).

When does my skylight need replacing?

Your skylight will need replacing after 10-15 years. Signs that it needs replacing include leaks, condensation, cracks on the glass or discolouration.

Your skylight might need replacing if:

  • It’s leaking
  • You notice condensation
  • There’s damp around the skylight
  • Discolouration on the glass
  • It’s older than 10 years
  • You’re replacing your roof

If your skylight’s glass is damaged, you should replace or repair it as soon as possible as it could break and pose a danger to people using the space.

At Dakea, our skylights come with a 5 year guarantee, and our roof windows with a 20 year guarantee. Roof windows are for occupied rooms such as loft bedrooms, bathrooms or living spaces. While skylights are for unoccupied rooms like garages or storage lofts.

Should you replace skylights when reroofing?

You should replace a skylight when reroofing if the skylight is old or damaged. If you’re likely to need to replace it in the near future, it can save you money to do it at the same time as replacing your roof.

A roofer in a orange safety jacket checks the pivot of a newly installed window


How to choose a replacement skylight

When choosing a replacement skylight, you should first consider whether a skylight or roof window is more suitable for your requirements.

If you’re looking for a window for an occupied room, you should select a roof window instead of a skylight.

Skylights are ideal for providing light and ventilation to unoccupied rooms such as storage lofts and garages, but they don’t have the insulative qualities needed for occupied rooms.

Roof windows, on the other hand, are designed to help provide light, ventilation and insulation to rooms that are used as living spaces.

When choosing a roof window or skylight, consider which of the following are important:

  • Insulative qualities
  • Noise reduction qualities
  • Wood or PVC frame (PVC is better for rooms with a lot of moisture, like bathrooms)
  • Size
  • Angle – flat or sloped roof
  • Cost

If you want your roof window to be highly insulative for sound and heat, it is likely to be more expensive. Depending on your budget, you might want to discuss with your supplier which skylight or roof window best balances your priorities.

How much does it cost to replace an existing skylight?

The average cost to replace an existing skylight is roughly £500. The skylight itself will cost £160 – £300, depending on size (or more if you’re looking for a roof window), plus the cost of installation.

However, it can depend a lot on whether you’re also replacing the roof. If you replace the roof and the skylight at the same time, the cost of replacing the skylight is likely to be less than doing the two things separately.

View the Dakea’s skylight prices by size.


How to replace a skylight

To replace a skylight as a homeowner, you should talk to a professional roofing contractor or window installer. This will ensure the window is installed correctly, preventing leaks. If you’re a professional, read our step-by-step guide below.

Can you replace a skylight yourself?

You shouldn’t replace a skylight yourself unless you have significant roofing experience. It can be easy to get wrong, leading to leaks and potential damage to your home.

These are instructions on how to install a Dakea skylight. If you’re installing a different skylight, the instructions might also be applicable, but we recommend consulting the manufacturer’s guide. If you’re replacing a roof window, our guide on installing a roof window might be more helpful!

1. Remove the old skylight

It will depend on whether the roof is also being replaced as to the exact way to remove the old skylight. Use the following as a guide, but it may need adjusting depending on other roof work.

  • Remove the tiles around the window. This is likely to be a fairly wide area in order to fully expose the flashing and any foil barriers.
  • Remove the flashing and membranes to expose the skylight window. The brackets holding the skylight in place should be exposed.
  • The window should then be able to be removed. This might require the use of a crow bar or similar tool to ease the window out.
  • Safety remove the roof window out of the area. Be careful not to drop or damage the glass as this could pose a hazard.


2. Choose the side for the opening mechanism on the new skylight

  • To change the side the skylight opens, open the skylight and unscrew the fixtures holding the sash in place.
A skylight window with the screws on the right being removed


  • You can then turn the sash by 180 degrees and reattach to the opposite side.

Be sure to re-screw all the fixtures into their new positions, then close the window securely.

Two screws, highlighted in orange, being unscrewed into the fixture on the top of the skylight

3. Position and secure the skylight

  • Line up the centre of the skylight with the centre of the hole in which the window will be positioned on both the length and height sides. This ensures a tidy finish.
  • Nail the skylight into place.


4. Complete any gaps in the roof tiles

Ensure that all the roof tiles are replaced. Cut any tiles to the correct size as needed.

Looking for a high quality skylight or roof window for your build? Request a quote from Dakea.

Related articles


How to open skylight windows

This is primarily a guide on how to open skylight windows from Dakea. If you’re looking for information on ... read more

Flashing roofers replacing a roof

What is Skylight Flashing?

Skylight flashings are designed to provide the weatherproofing junction between the roof window or skylight... read more

Windows two open roof windows

Roof Window Types

Learn the different types of roof window with this guide. read more

Join our newsletter!

Are you a professional installer, contractor, or housebuilder? Sign up for our newsletter today to be the first to hear about new products, promotions and exclusive offers.

For all other enquiries please complete our contact form on our website.