Root resistant membrane systems — planter boxes and podiums

ARDEX Root Repell (also referenced as ARDEX WPM 1000 RR) is ARDEX Australia's dedicated weldable root resistant waterproofing sheet membrane for planter boxes, retaining walls, green roofs, and damp-proofing applications. The membrane is a polypropylene-lined waterproofing sheet incorporating Preventol B2 — a premium chemical root inhibitor that repels root growth without systemic action that would kill the plant above. The polypropylene lining provides a consistent 1.2mm membrane thickness across the full installation.

Laps and seams are heat-welded using a Leister hot air gun and rolled with a rubber roller to ensure continuous watertight seams. The heat-welded seam is stronger than the membrane itself. Roll size is 1.4m × 20m — available through ARDEX Australia and waterproofing trade stockists. Flood testing, tiling, and screeding can begin one hour after membrane installation. Compatible with selected ARDEX tiling systems and ARDEX water-based liquid-applied membranes — confirm compatibility with ARDEX technical before combining with other products.

Important substrate and installation notes from the ARDEX TDS: ARDEX engineered screeds must not be applied directly to ARDEX Root Repell. LOSP (Light Organic Solvent Preservative) treated plywood must not be used under ARDEX Root Repell under any circumstances. The membrane must not be exposed to UV for more than 30 days without protection. Application must be carried out by an ARDEX Accredited Applicator.

Wolfin IB is FLL-certified for root penetration resistance — confirmed through independent testing under the German FLL standard using aggressive root-forming plant species. The root resistance of Wolfin is a material property of the PVC compound — roots cannot physically penetrate the dense, flexible polyester-reinforced PVC sheet. This is a passive mechanical resistance that does not rely on a chemical inhibitor and does not degrade over time as a chemical additive might. Wolfin has been installed in Australian planter boxes and green roofs since the late 1980s — a 2018 Projex Group case study confirmed Wolfin membrane found intact and unpenetrated after 11 years of service in planter boxes containing bamboo at a Bella Vista corporate facility.

In planter box and podium slab applications, Wolfin IB is loose-laid over the prepared substrate with adjacent rolls overlapped and hot-air welded. The welded seam is stronger than the membrane field. Wolfinsteel profiles (galvanised or 316L stainless) are used for perimeter termination, upstand details, and wall junctions — all fixings are encapsulated within the profile body and welded to the membrane, eliminating exposed mechanical fixings that roots could follow. Protection board or dimple mat is placed above the membrane before growing medium is installed.

Every Wolfin installation is inspected and signed off by Projex Group, resulting in a single-point warranty on workmanship and materials for up to 15 years issued to the building owner.

Cosmofin FG is the Projex Group's second FLL-certified root-resistant PVC sheet membrane, distinct from Wolfin IB in that it is supplied with a fleece backing that allows tile adhesive to bond directly to the membrane surface — making Cosmofin FG LL suitable for under-tile balcony and terrace applications as well as planter box and green roof use. Like Wolfin, Cosmofin achieves root resistance through the material properties of the PVC compound (FLL tested and certified) rather than through a chemical inhibitor. Hot-air welded at seams. Pre-made factory corner pieces and drain outlets are supplied in the same PVC material as the membrane, ensuring full system compatibility.

In planter box and podium slab applications on Australian strata buildings, Cosmofin is used where the project requires a root-resistant sheet membrane that is also compatible with a tiled finish above — for example, a tiled podium courtyard over a planted basement or car park where the single membrane must address both root resistance below the growing medium and tile compatibility in the tiled areas.

Roll size: 1.65m × 15m, 2mm thick including fleece. NATA certified. AS 4654.1:2012 compliant (Cosmofin FG). Cosmofin FG LL also complies with AS 4858 for internal and wet area applications.

Tremco TREMproof 211 is a low VOC, high solids, single-component moisture-curing polyurethane waterproofing membrane designed primarily for planter box and below-grade waterproofing applications. For planter box use, TREMproof 211 is applied in conjunction with the TREMproof Anti-Root Additive — the additive must be mixed into the liquid membrane before application to provide root resistance. The combined product provides a liquid-applied root-resistant membrane suitable for the constant water immersion and biologically active conditions of planter box environments.

TREMproof 211 is tested to AS 4654.1 — Waterproofing membranes for external above-ground use. Single-component — moisture-curing — minimises application errors associated with incorrect mixing of two-component products. Low VOC formulation. Suitable for planter boxes, below-grade retaining walls, and applications where constant water immersion is expected.

Confirm with Tremco Australia that the Anti-Root Additive is included in the specification and correctly dosed before application — the membrane without the additive does not provide root resistance. Confirm the effectiveness of the additive against the specific plant species to be grown above, particularly for high-risk species such as bamboo, with Tremco technical before specifying.

Soprema Colphene 3000 is a self-adhering SBS-modified bitumen sheet membrane used for planter box waterproofing on concrete and blockwork substrates. It is applied by cold adhesion — no torch required — making it suitable for planter box applications where hot-work is restricted or impractical. It is available in Australia through Bayset as part of a documented planter box waterproofing system (Bayset System 510).

In the Bayset documented system, Colphene 3000 is applied to the planter box substrate and all penetrations and junctions are detailed using Soprema Alsan Flashing Quadro — a single-component root and rhizome-resistant polyurethane resin used for flameless waterproofing at junctions, upstands, and penetrations, incorporating Soprema Alsan Fleece 165 B reinforcing fabric at junctions. Aluminium K Flashing or Aluminium Pressure Seal is used to protect the exposed membrane edge at the top of the wall.

Confirm with Soprema Australia or Bayset that Colphene 3000 is currently available and that the system is appropriate for the specific planter box substrate, plant species, and project conditions before specifying.

Modified bitumen torch-on sheet membranes with anti-root cap sheets are an established waterproofing system for podium slabs, green roofs, and planter box applications in Australia. The system consists of a standard SBS-modified bitumen base sheet, torch-applied to the prepared substrate, followed by an anti-root SBS cap sheet as the top layer. The anti-root cap sheet is formulated to resist root and rhizome penetration from the growing medium above.

Tremco Australia supplies TREMproof torch-applied SBS modified bitumen systems for podium and roof applications, including anti-root variants for green roof and planter box applications. The torch-on anti-root system is one of the more commonly used approaches in Australian strata podium and planter box waterproofing remediation — it is familiar to Australian torch-on waterproofing contractors and the materials are accessible through Tremco Australia's distribution network.

Hot-work permit and site safety management required for torch-on application — confirm hot-work permit availability and site safety requirements with the building manager before specifying for strata buildings. Torch-on is not suitable where gas lines, combustible materials, or confined spaces near the application area make open-flame application a safety risk.