Flood test equipment and plugs

Inflatable rubber balloon flood test plugs are the standard drain sealing product for flood testing balcony and terrace waterproofing membranes on Australian residential and strata remediation projects. The rubber balloon is inserted into the drain outlet pipe in its deflated state, then inflated using a hand pump or air compressor — the expanded rubber body presses against the internal pipe wall to create a watertight seal. Available in 50mm, 75mm, and 100mm sizes to suit standard nominal pipe diameters.

The balloon is fitted with an air inflation valve and a tie-off ring or circle hook at the top — a rope or wire is attached to the tie-off ring before insertion to prevent the plug from dropping down the pipe if it deflates or is dislodged during the test. The tie-off rope should be tied off at the drain grate or an adjacent fixing point before filling commences. After the flood test is complete, the balloon is deflated and removed from the drain.

Confirm the pipe internal diameter before ordering — the balloon must match the actual internal diameter of the drain outlet pipe, not the nominal pipe size. On remediation projects, the existing drain pipe internal diameter may differ from the nominal size due to age, pipe type, or previous modifications. Measure the pipe ID before ordering plugs.

Mechanical aluminium expansion plugs use a wing nut and plate mechanism to compress a rubber gasket against the internal pipe wall, expanding the plug body to create a seal. Unlike inflatable balloon plugs, mechanical expansion plugs do not require air pressure — they are tightened by hand to the correct compression level. Available in a range of sizes covering standard pipe diameters from 38mm (1½ inch) through to 100mm (4 inch) and larger.

Mechanical expansion plugs are used in flood testing where the drain pipe internal surface is irregular, out-of-round, or where the rigidity of the plug body provides a more reliable seal than an inflatable balloon. They are also preferred on some commercial and strata remediation projects where the specifier or QA protocol requires a mechanical plug rather than an inflatable format.

The plug is inserted into the drain outlet, the wing nut is tightened until the rubber gasket is firmly compressed against the pipe wall, and the balcony is filled. After the test, the wing nut is loosened and the plug is removed. Reusable. Confirm the pipe internal diameter before selecting the correct plug size — mechanical plugs are sized to a specific pipe diameter range, not a single size.

Plumtest inflatable rubber test plugs (distributed through Plumbers Choice and plumbing trade suppliers) are a standard plumbing trade format inflatable drain bung for flood testing and pipe pressure testing. Available in 50mm and 100mm sizes for standard pipe diameters. The rubber body is inflated to seal against the internal pipe wall, the area is filled, and the plug is deflated and removed after the test.

This is a widely available plumbing trade product stocked through plumbing suppliers across Australia — Plumbers Choice, Reece, Tradelink, and similar. It is a practical alternative to waterproofing-specific flood test balloon products where the waterproofing supplier does not stock inflatable plugs or where plumbing trade supply is more convenient for the project.

Confirm the plug size against the actual internal pipe diameter before ordering. The 100mm plug suits standard 100mm nominal floor waste drain outlets on residential balconies. The 50mm plug suits 50mm nominal pipe diameters used in some linear drain and secondary outlet applications.

The Stormtech 100FLEX is a 100mm neoprene flexible rubber puddle flange with an integrated, removable flood test plug built into the flange body. The flood test plug is a purpose-designed component of the 100FLEX system — it seals the drain outlet without requiring a separate inflatable balloon or mechanical plug. A small incision in the plug base allows water to be released after the test. A water level gauge is also built into the flange, simplifying the process of monitoring water depth during the flood test.

The 100FLEX is CodeMark Australia certified (CM40377) for internal and external wet area applications on concrete substrates and carries a lifetime warranty. In balcony waterproofing remediation, the 100FLEX is specified where the project calls for an integrated, all-in-one puddle flange and flood test solution — the flange provides the membrane integration at the drain point and the flood test plug and gauge are built in, eliminating the need to source, size, and manage separate flood test equipment.

This product is listed on this flood test page as a reference for specifiers who are selecting puddle flanges and want to be aware that integrated flood test plug options exist. The full puddle flange specification for this product should be confirmed on the Drainage Puddle Flanges page.

A water level gauge or depth marker is used during the flood test to record the starting water level and monitor any drop in water level over the test period. Without a reference mark, it is impossible to accurately assess whether any reduction in water level during the test is due to membrane leakage or evaporation. The gauge does not need to be a purpose-manufactured product — a pencil mark on the wall or upstand at the starting water level, combined with a small evaporation reference container on the balcony surface, is sufficient for a standard residential balcony flood test.

On larger or more formal strata remediation projects, a purpose-made gauge tube — a transparent PVC tube fixed vertically to the wall or upstand with graduations marked in millimetres — provides a more accurate and auditable water level record for the flood test certificate. Some puddle flange systems (such as the Stormtech 100FLEX) include a built-in water level gauge at the drain.

The evaporation reference container — a small open container of water placed on the balcony surface at the start of the test — allows the evaporation rate at the balcony microclimate to be measured over the test period. The measured evaporation from the reference container is deducted from any apparent water level drop in the balcony before a fail determination is made.