Is it necessary to remove the old roof prior to the installation of a new EPDM roofing system?
Is it necessary to remove the old roof prior to the installation of a new EPDM roofing system?
In some cases, removing the old roof before installing an EPDM over the top is not always necessary. However, it depends on the existing roof whether the underlying roof deck is compatible with the structure and intact. If you know the underlying deck is compatible and plan to install EPDM, we recommend placing a barrier in between, like a new layer of plywood or a fibreglass-backed OSB board.
Our rubber sheets can generally be installed over old roofs, especially if the existing roof is in good condition and correctly prepared. Explore our membranes.
Types of surfaces EPDM can be laid on:
- Roofing-grade plywood and wood planks
- Oriented strand board or sterling boards
- Steel decks (use a metal primer and adhesive)
- Asphalt-based roofs or BUR (adhesive suitable for asphalt surfaces)
- Lightweight concrete (suitable adhesives and primers)
- View all.
Generally speaking, as long as the underlying deck is sound, it’s OK to overboard. However, please check compatibility with us beforehand if you’re unsure. We’ll understand the manufacturer instructions, which state what products are compatible with your existing roof material—some have specific requirements and recommendations. It will also be important to uphold your warranty, as some types might require a full tear-off.
When not to install EPDM over an existing system
- The underlying roof must be in good condition to be considered a suitable base. Ensure to inspect the roof for any significant damage. For example, you’ll need to reroof or repair in cases of large tears, extensive wear, and blisters.
- Don’t install EPDM on top of a felt roof without using Fleece Backed EPDM to protect the roof’s original coating.
- Seek advice if you’re planning to place EPDM over existing EPDM. While installing rubber on top of rubber is possible, it’s not always recommended. For example, it can cause condensation to build up between the layers.
- If the new roof materials, additional layers, and insulation exceed the building’s load-bearing capacity, the old roof will need to be removed.
