Terminations

Membrane termination is one of the fundamental aspects of successful waterproofing systems. Terminating the membrane adequately is a detail often overlooked and one that is critical to the success of the system as a whole.

Membranes start at a high spot and finish at a low spot and these are usually the areas that require careful termination so as to prevent water ingress below the waterproofing system affecting the substrate below.

We can achieve this in a number of ways, namely, mechanical, chemical and a combination of both.

Bitumen Sheet Membrane

This upturn termination is chemical fixing only - relying on the bond of membrane, primer and substrate.

Mechanical anchors are typically made up of metal flashings, clamps, and bars that are secured using screws to mechanically terminate the membrane to the substrate. Another type of mechanical termination is manipulating the substrate to create an anchor for the membrane to terminate into. This is achieved by creating a 45-degree inverted cut into the substrate. The membrane (typically liquid) terminates into this cut to create a mechanical anchor. This method does border between mechanical and chemical but it’s own category is hard to define. This is typically used in instances where mechanical fixing is not feasible or aesthetically intrusive to the design. Mechanical fixing is also used in high and low spots such as plastic or metal pipes and certain puddle flanges. In these areas we can use clamps tightened creating a termination between the pipe and membrane. Puddle flange clamps can also be used to secure the membrane to the flanges ensuring a tight seal.

EPDM Membrane

This EPDM system is fixing to the substrate using termination bar.

To a lesser degree, cladding and other building envelope materials help fix membranes in place externally.

Chemical and mechanical fixing is essentially the combination of both methods. Granted the former is used in most instances as most membranes require priming but mention of this is important as it is a form of fixing, just to a weaker degree.