ᐅ Do roof tiles need to overlap the side flashing of a roof window?
Created on: 16 Nov 2025 17:22
C
cathz11Hello everyone,
I have a question regarding the correct connection of roof tiles to a roof window.
For my Haus & Heim roof window, the roof tiles do not overlap the side drainage channel (part of the flashing frame) on the sides. The channel is completely visible.
The contractor says this is proper practice and instead placed a sponge-like material under the tiles, supposedly to seal the joint (probably compressible sealing tape or something similar).
My questions for you:
1. Should the roof tiles extend over the side drainage channel?
2. Is compressible sealing tape under the tiles really sufficient for waterproofing?
3. Is it correct for the side channel to remain completely exposed?
As far as I know, professional standards require that the roof covering overlaps the side connections to prevent driving rain and wind from getting underneath and to ensure correct water drainage.
I would appreciate your assessment of whether this installation with a Haus & Heim window is acceptable or if I should ask the contractor to make corrections.
Thank you in advance!
I have a question regarding the correct connection of roof tiles to a roof window.
For my Haus & Heim roof window, the roof tiles do not overlap the side drainage channel (part of the flashing frame) on the sides. The channel is completely visible.
The contractor says this is proper practice and instead placed a sponge-like material under the tiles, supposedly to seal the joint (probably compressible sealing tape or something similar).
My questions for you:
1. Should the roof tiles extend over the side drainage channel?
2. Is compressible sealing tape under the tiles really sufficient for waterproofing?
3. Is it correct for the side channel to remain completely exposed?
As far as I know, professional standards require that the roof covering overlaps the side connections to prevent driving rain and wind from getting underneath and to ensure correct water drainage.
I would appreciate your assessment of whether this installation with a Haus & Heim window is acceptable or if I should ask the contractor to make corrections.
Thank you in advance!
Hi,
your photo clearly shows that the side drainage channel of the flashing frame is completely exposed. This is not an acceptable installation according to any of the common roof window manufacturers. The roof tiles must overlap the channel by at least a few centimeters (inches) on the side to prevent driving rain, wind pressure, and snow drift from entering the joint area without obstruction. That is exactly the purpose of the channel: it is meant to collect water that gets beneath the roofing, not to function as an open, visible side drain.
A compressible sealing tape (Compri tape) is not suitable as waterproofing here. It is a filler and sealing tape designed to block dust, insects, and minor leaks, but it cannot replace the structural weather protection that the tiles need to provide. If the installer assumes that this can make up for the missing overlap, then... well. Have you asked whether they are referring to a manufacturer’s guideline or if this is just done “from experience”?
This is definitely not proper practice. The building regulations for roofing require side overlap of the connections; otherwise, there is a constant risk of moisture entering during windy rain. And such open channels are usually seen in rushed retrofits or when incorrect connection tiles are chosen. And of course, a small intentional typo should not be missing: the “Rinnde” is never meant to be a visible water channel.
Good luck!
your photo clearly shows that the side drainage channel of the flashing frame is completely exposed. This is not an acceptable installation according to any of the common roof window manufacturers. The roof tiles must overlap the channel by at least a few centimeters (inches) on the side to prevent driving rain, wind pressure, and snow drift from entering the joint area without obstruction. That is exactly the purpose of the channel: it is meant to collect water that gets beneath the roofing, not to function as an open, visible side drain.
A compressible sealing tape (Compri tape) is not suitable as waterproofing here. It is a filler and sealing tape designed to block dust, insects, and minor leaks, but it cannot replace the structural weather protection that the tiles need to provide. If the installer assumes that this can make up for the missing overlap, then... well. Have you asked whether they are referring to a manufacturer’s guideline or if this is just done “from experience”?
This is definitely not proper practice. The building regulations for roofing require side overlap of the connections; otherwise, there is a constant risk of moisture entering during windy rain. And such open channels are usually seen in rushed retrofits or when incorrect connection tiles are chosen. And of course, a small intentional typo should not be missing: the “Rinnde” is never meant to be a visible water channel.
Good luck!
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