Skip to content
We deliver to all locations, Australia wide.
We deliver to all locations, Australia wide.
The Essential Guide to Installing Back Tray Flashing with a VELUX Skylight

The Essential Guide to Installing Back Tray Flashing with a VELUX Skylight

When it comes to skylight installation, ensuring a waterproof integrity is paramount, especially on roofs with a pitch below 15 degrees. Our solution? Install a back tray flashing – a critical component designed to prevent leaks and protect your home. This guide will walk you through the steps to properly install a back tray flashing with a VELUX skylight, applicable to a variety of roof profiles including Corrugated, Trimdeck, Kliplok, and Spandeck.

Why Back Tray Flashing is a Must

Installing a back tray flashing is highly recommended for any skylight positioned on a roof pitch under 15 degrees. Its design effectively removes the section of roofing sheet behind the skylight. As a result, when rain hits the back tray, it seamlessly diverts water into the sheet pan on either side of the flashing, preventing any potential leaks.

Installation Steps to Follow

Here's a guide to ensure your back tray flashing installation goes smoothly, applicable to most roof types:

  1. Positioning the Back Tray: The back tray should extend from the rear of the skylight to the roof's highest point. Typically, it connects to the apron flashing at the top.

  2. Sizing the Back Tray: Make sure the back tray's width spans an additional dry pan – that's 2 ribs for Kliplok and Trimdeck profiles, and 3 ribs for Corrugated and Spandeck profiles.

  3. Oversize Back Trays: If the back tray exceeds a 1200mm width, segment the installation into 1200mm sections up the roof. 

  4. Base Flashing First: Always install the skylight's base flashing before the back trays.

  5. Securing the Back Tray to Base Flashing: The back tray should begin at least 80mm behind the skylight. Seal the joint underneath and use pop rivets at 40mm intervals. For additional protection, underseal and overseal the joint with a polyurethane sealant, which is available from our online store - Click here - Fixings Click here - Sealants  

  6. Installing Additional Back Trays: Continue adding back trays up the roof until you connect with the top flashing. Ensure all joints overlap by at least 80mm, are sealed both under and over, and are pop riveted at 40mm intervals.

  7. Fixing the Back Tray: Use the same size fixings as those securing the roof, following the roof profile's pattern and fixing into the roof batten.

Ensuring a Waterproof Installation

By adhering to these steps, you can ensure a robust, leak-proof installation for your VELUX skylight, even on low-pitched roofs. Remember, the key to a successful skylight installation is not just in choosing the right products but also in the precision of the installation process. With the back tray flashing in place, you can enjoy the natural light and aesthetic benefits of your skylight without the worry of water intrusion. 

Shop back tray flashings - Click Here

For more informaton and advise please reach out to our team - sales@shireskylights.com.au or 02 9542 8287

Next article Our guide to Buying Skylights Online