Is your roof window leaking during periods of torrential rain? Here are some things to check before you call someone out:
Have you checked the appearance of the roof to make sure there are no incorrectly cut or damaged tiles/slates? The water may be coming in from another part of the roof but seep in through the window opening.
Is your roof covering compatible with your roof pitch? Before installing a roof window, your contractor completing the works should check the tiles, roof window and pitch of roof are compatible with each other. If this step is avoided during the build process, you may need to rectify any issues in future years and may invalidate warranties with the manufacturers.
We find that 90% of roof windows that leak are on a ground floor extension with a pitch lower than 15 degrees. Often the roof tiles are not appropriate for the pitch of roof to begin with and there are only a few types of tiles that can go on a low pitch roof. We would advise that you check that the roof tiles that have been specified/installed are fit for purpose in the first instance. Most roof windows have a minimum roof pitch requirement of 15 degrees but there are some roof window manufacturers who can offer a low-pitched roof window option which can go as low as10 degrees for some sizes.
Have your windows been serviced since installation? Lack of servicing over time can encourage leaking as the flashings should be cleared regularly to avoid debris build up. Rainwater loves to nestle in debris which can affect the effectiveness of flashings over time. Alongside this, the screws/flashing parts and butyl putty may become loose over time which during service we would check the condition and report back to you as the homeowner with any recommendations we have. For more information about servicing, check out our servicing FAQ blog below:
If you are struggling to find out your roof pitch. You can use VELUX’s free smartphone app ‘VELUX roof pitch’ which is available on Apple and Android devices. If your window was fitted prior to September 2021, your window should be fitted at a minimum of 15 degrees. The larger the window, we recommend raising the window up as much as possible so any rain would disperse away from the window to prevent water pooling.
Condensation
Are you opening and closing your windows regularly to allow condensation to vacate the room? This is important all year round to ensure your room is well ventilated. Most roof windows have a vent bar at the top to allow fresh air to circulate. Condensation usually forms on the glass panes and in the corners of the window frame and sometimes can drip onto plasterboard if the build-up is severe. We would recommend if the leak is a small amount to try wipe the water away and ventilate the window in dry weather for 1 hour to see if the leak returns once raining again.