Key points
How TPO waterproofing should be considered with aluminum panels, substrate, insulation and other roof construction layers.
Waterproofing is a system layer
TPO is not simply an extra sheet placed below an aluminum panel. Its role depends on the roof build-up, drainage, interfaces and construction sequence.
Confirm compatibility
The design should check contact between layers, movement, penetrations, edges, gutters and the materials used around the membrane.
Project conditions decide the detail
Slope, climate, insulation, substrate and maintenance requirements should be reviewed before deciding whether and how a TPO layer is used.