Termination bar

A termination bar is a metal bar mechanically fixed (with a sealant bead) to clamp the top edge of a waterproofing membrane at an upstand or wall. It is the mechanical termination that AS 4654.2 requires, because bonded-only terminations tend to fail at around 5 to 10 years.

Where a membrane turns up a wall (a balcony, a planter, a wet-area hob), the top edge has to be held and sealed so water cannot get behind the membrane at the top. There are two ways to do it:

• Bonded only: the membrane is just stuck to the substrate at the top. Over time the adhesive at the exposed top edge dries, the membrane peels back, and water tracks behind it. This is a common cause of balcony and planter leaks a few years after handover.
• Mechanically terminated: a termination bar (an aluminium or stainless strip) is fixed through the membrane into the substrate at the top edge, with a continuous sealant bead capping it, so the edge is clamped and the seal is maintained by the fixings, not just adhesion.

AS 4654.2 (and good practice) calls for a mechanical termination at the top of upstands for exactly this durability reason.

For a builder the practical points are to detail a termination bar (or an equivalent mechanical termination, a chase, a counterflashing) at the top of every membrane upstand, not just bond the edge, to seal over the bar continuously, and to set the upstand height so the bar sits well above the finished surface and any likely water level. Skipping the bar to save a strip of aluminium is a textbook way to buy a balcony leak in year five. See membrane upstand termination.

Also known as: Termination strip, membrane clamp bar.

Category: Waterproofing / Membranes.

Related

• AS 4654.2 membrane design
• Membrane upstand termination

See also

• Waterproofing membranes

References

• AS 4654.2 Waterproofing membranes, Design and installation, Standards Australia (verified 2026-06-01)

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Last updated: 2026-06-01. Verified: 2026-06-01. Quarterly review for currency.