Repair Systems — Flood Test Equipment
Flood test equipment and plugs
Technical product reference for flood test equipment and drain plugs used to verify waterproofing membrane integrity on balconies and terraces in Australian Class 2 strata apartment buildings — inflatable rubber plugs, mechanical expansion plugs, integrated puddle flange plug systems, water depth gauges, and AS 3740 flood test requirements.
What is flood test equipment?
Flood test equipment seals a balcony or wet-area drain so the floor can be flooded to a known head of water to prove the waterproofing membrane is watertight before tiling or overburden. It ranges from inflatable rubber balloon plugs and mechanical wing-nut expansion plugs that seal the drain outlet, through integrated puddle-flange plugs (e.g. Stormtech 100FLEX), to the water level gauge and evaporation reference that make the pass/fail assessment accurate and auditable. Selection turns on matching the plug to the actual pipe internal diameter, a reliable tie-off, and documenting the water level and evaporation. Confirm sizes and availability against current Australian supplier data.
Product Reference
Individual products — one card each — scroll to view all
H2O Supplies / The Waterproofing Shop / various
Inflatable Rubber Flood Test Balloon Plug
Inflatable rubber drain plug for flood testing
Inflatable rubber balloon plugs are the standard drain-sealing product for flood testing balcony and terrace membranes. The deflated balloon is inserted into the outlet pipe then inflated by hand pump or compressor to press against the internal pipe wall, holding the test head for a minimum 24-hour test. A tie-off ring lets a rope be secured before insertion to prevent loss down the pipe. Available in 50/75/100mm; confirm the actual pipe internal diameter before ordering.
Plumboss / Drainchem / plumbing trade
Mechanical Expansion Test Plug — Aluminium
Mechanical wing-nut expansion drain plug
Mechanical aluminium expansion plugs use a wing nut and plate to compress a rubber gasket against the internal pipe wall, expanding the body to seal without air pressure. They suit flood testing where the pipe bore is irregular or out-of-round, or where the QA protocol calls for a mechanical rather than inflatable plug. Sized to pipe-diameter ranges from about 38mm to 100mm+. Confirm the size against the actual pipe ID.
Plumtest / Plumbers Choice
Plumtest Inflatable Test Plug
Plumbing-trade inflatable rubber bung
Plumtest inflatable rubber test plugs (via Plumbers Choice and plumbing trade) are a standard plumbers-bung format for flood testing and pipe pressure testing, in 50mm and 100mm sizes. The rubber body inflates to seal against the internal pipe wall, then deflates for removal after the test. Widely stocked, they are a practical alternative where the waterproofing supplier does not stock inflatable plugs. Confirm the size against the actual pipe ID.
Stormtech
Stormtech 100FLEX — Integrated Flood Test Plug
Puddle flange with built-in flood test plug & level gauge
The Stormtech 100FLEX is a 100mm neoprene puddle flange with an integrated, removable flood-test plug and a built-in water level gauge, eliminating the need for a separate drain plug. A small incision releases water after the test. It is CodeMark Australia certified (CM40377) for internal and external wet areas on concrete. Confirm the full puddle-flange specification on the Drainage Puddle Flanges page and membrane compatibility with Stormtech.
Various / site-fabricated
Water Level Gauge / Depth Marker
Flood-test water-level reference & evaporation allowance
A water level gauge or depth marker records the starting water level and monitors any drop over the flood-test period, so leakage can be distinguished from evaporation. A pencil/tape mark on the upstand plus a small open evaporation-reference container is sufficient for a standard residential balcony; a graduated PVC gauge tube gives an auditable record on larger projects. Some puddle flanges (e.g. Stormtech 100FLEX) include a built-in gauge.
System Comparison
Flood test equipment — confirm all selections against the current manufacturer TDS before specifying.
Scroll the table sideways to see every column →
THE FLOOD TEST IS A MANDATORY HOLD POINT — DO NOT TILE BEFORE THE MEMBRANE HAS BEEN TESTED AND PASSED
The flood test is a mandatory quality assurance hold point in every compliant balcony waterproofing scope on Class 2 strata buildings. Tiling must not commence until the membrane has been flood tested, the test has passed, the result has been documented, and the waterproofing consultant or certifier has confirmed the hold point is cleared. Tiling over an untested membrane permanently conceals any membrane defects — defects that would have been identifiable and repairable during the test become inaccessible after tiling and will result in water ingress that requires full tile and membrane removal to rectify. The cost of skipping the flood test is never justified by the time saved.
CONFIRM THE PLUG SEALS CORRECTLY BEFORE FILLING — DO NOT FILL OVER A LEAKING PLUG
Before filling the balcony with water, confirm that the flood test plug is correctly seated and not leaking around its perimeter. Fill the drain body immediately around the plug first and observe for 5 minutes — any water tracking past the plug into the drain pipe is a plug failure, not a membrane failure. If the plug is leaking, remove it, check the plug size against the pipe ID, re-seat or replace it, and reconfirm the seal before proceeding to fill. Filling over a leaking plug will produce a false fail result — the water level will drop due to plug leakage, not membrane deficiency — and will waste the test period.
CHECK THE STRUCTURAL LOAD CAPACITY OF THE BALCONY BEFORE FLOOD TESTING LARGE AREAS
Water at 25mm depth imposes approximately 25 kg/m² on the balcony slab. On large balcony areas, podium decks, or older strata buildings where the balcony structural capacity may be limited or unknown, confirm with the structural engineer that the flood test water load does not exceed the balcony's design imposed load before conducting the test. This is particularly important where the flood test depth is increased above 25mm or where the balcony slab is known to be in a compromised condition. Do not assume all balconies can sustain a flood test load without engineering confirmation on large or older structures.
DOCUMENT THE FLOOD TEST — A VERBAL PASS IS NOT A QA RECORD
The flood test result must be documented in writing as part of the project QA record. The flood test certificate must include: project address and balcony location, date and start and end time of the test, water depth at commencement and at the end of the test period, evaporation allowance applied, weather conditions during the test, name and licence number of the waterproofing applicator, pass or fail result, and the applicator's signature. On Class 2 strata remediation projects, the flood test certificate is typically required by the strata manager, owners corporation, or certifier before tiling proceeds. Photographs of the plug in place, the starting water level mark, and the final water level mark should be retained with the certificate.
Disclaimer
This page provides general technical information only. Final product selection and flood test procedures must be confirmed against the current AS 3740:2021 requirements, project specification, waterproofing consultant requirements, certifier requirements, drain outlet diameter, and structural engineer advice where applicable for large area flood testing. The flood test is a mandatory hold point — tiling must not commence before the membrane has been tested, passed, and the result documented. Do not rely on this reference as a substitute for professional waterproofing consultant advice.