What to do if your slated roof is thicker than 8mm

Posted by Becky Graham on 3rd August 2017

In this blog, you can learn how to adapt the EDW flashing to Cambrian slates or slates that are thicker than 8mm.

Usually on a slated roof the EDL flashing would be the ideal flashing. However, there can be times when your slated roof is thicker than 8mm and in this case, you need to use the EDW universal flashing. By following the steps below, you can see how to adapt this EDW flashing to the slates on your roof.

  • As per the fitting instructions, the bottom support batten must be fitted 80mm above the top edge of the last full course of tiles below the window. 
  • The window should then be fitted and adjusted as per the window fitting instructions.
  • The BFX Underfelt collar should then also be fitted as per the instructions.

Please note: The BFX Underfelt Collar is optional but it will ease the installation process.

The EDW Flashing Kit Should then be fitted incorporating the following steps (pictures included):

Step 1:
Fit the bottom apron piece and compress the corrugation at the point of overlap with the tile above.

Step 2:
Then you need to trim the foam. The very outer turnback can be bent to sit a little flatter to allow you to place verge hooks against the large metal upstand.

Step 3:
The next tile to the bottom left and bottom right should then be a double tile, which should be trimmed to the side of the metal upstand. Where the tile sits against the fold in the aluminium, a small “notch” should be taken out to allow the tile to sit. Should look as pictured below.

Step 4:
The next tile should be a tile-and-a-half, which should also be trimmed to the side of the metal upstand.

Step 5:
Double tile and tile-and-a-half should then be alternated up the side of the window until the top, as shown below.

Step 6:
Once at the top of the window, the tiles going around the head of the window will need to be trimmed to allow a gap of between 60-150mm from the head of the window to the lower edge of tile. The tiles will then be secured using verge clips at the left and right-hand side. Slate hooks will be used for the tiles directly above the window.

If you have any further questions after reading this blog, feel free to contact VELUX directly on 01592 778 225.