Repair Systems — 02 — Concrete & Structural Defects
Polyethylene curing sheeting
Technical product reference for 200–250 µm clear and black LDPE polyethylene builder's plastic used as wet curing membranes over fresh repair mortar in concrete spalling repair. Covers thickness selection, clear vs. black grades, edge sealing requirements, and extended curing applications.
Curing sheeting in concrete spalling repair
Polyethylene curing sheeting is a critical but often overlooked consumable in concrete spalling repair. After placing repair mortar, the mortar must be protected from moisture loss during the initial curing period — typically 3 to 7 days — to achieve its specified compressive strength and durability. Premature drying causes plastic shrinkage cracking, reduces surface strength, and can cause the repair to delaminate. Covering the fresh mortar with polyethylene sheeting as soon as initial set has occurred traps moisture against the mortar surface and maintains the high humidity environment required for cement hydration.
Product Reference
Individual products — one card each — scroll to view all
Packline Australia
Packline 200 µm Clear LDPE Builder's Plastic
200 µm clear LDPE polyethylene sheeting — concrete curing membrane
Packline 200 µm clear LDPE polyethylene sheeting is a standard builder's plastic sheeting used as a wet curing membrane in concrete spalling repair. After applying repair mortar and achieving initial set, the mortar surface is covered with polythene sheeting and weighted or taped at edges to trap moisture against the fresh mortar surface. This maintains a high humidity environment around the fresh mortar through the initial curing period — typically 3 to 7 days depending on mortar type, ambient temperature, and wind exposure.
Tuff Wrap / National Plastics
Tuff Wrap 200 µm Black LDPE Builder's Plastic
200 µm black LDPE polyethylene sheeting — curing membrane and protection
Tuff Wrap 200 µm black LDPE builder's plastic is a heavy-duty black polyethylene sheeting used as a curing membrane for fresh repair mortar where direct sunlight exposure would cause overheating under a clear membrane. Black sheeting reflects less solar radiation than clear but its primary advantage is that it absorbs and dissipates rather than concentrating heat under the membrane. In practice, on outdoor horizontal repairs in summer, the recommendation is to wet the mortar surface, apply black sheeting, and shade the sheeting with hessian or shade cloth for best temperature control.
Bunnings Trade / Independent Hardware
Builder's Plastic Sheeting — 200 µm Clear (Generic Supply)
200 µm clear polyethylene builder's plastic — general trade supply
Generic 200 µm clear builder's plastic sheeting available from Bunnings Trade, Mitre 10, and independent hardware suppliers is a practical curing membrane option for small patch repairs and repairs in low-wind indoor environments such as carparks and building interiors. This grade of sheeting is identical in function to branded builder's plastic — the key specification is 200 µm minimum thickness, which provides adequate durability for short cure periods of 3–7 days. Thinner sheeting (100–150 µm 'drop sheets') should not be used for curing as they tear easily and do not trap moisture reliably.
Packline / Generic Supply
Heavy Duty 250 µm LDPE Sheeting
250 µm heavy-duty LDPE sheeting — extended curing and weather protection
Heavy-duty 250 µm LDPE polyethylene sheeting is used when a more durable curing membrane is required — for extended cure periods exceeding 7 days, in windy outdoor environments where standard 200 µm sheeting is prone to tearing, and for vertical or overhead curing where the membrane must hold reliably under its own weight when taped or fixed. For post-tensioned slab repairs and high-specification structural repairs where extended moist curing is specified (14–28 days), 250 µm sheeting provides a more reliable long-term moisture barrier than standard 200 µm film. Available from Packline Australia in clear and black variants and from trade plastics suppliers nationally.
System Comparison
Concrete spalling — confirm all selections against the current manufacturer TDS before specifying.
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Do not confuse curing sheeting with:
- Lightweight drop sheet plastic (100–150 µm) — thin drop sheets used for painting protection look similar to builder's plastic but tear easily during concrete curing, do not provide reliable moisture retention, and should not be used as curing membranes — use minimum 200 µm builder's plastic
- Spray-applied curing compounds — liquid acrylic or wax-emulsion curing compounds are an alternative to sheeting curing — they are applied by spray after initial set and form a thin film — listed on the curing compounds page — confirm from the repair mortar TDS whether sheeting or spray compound curing is specified
- Vapour barrier membranes — 200 µm polythene used as an under-slab vapour barrier is the same material but a different application — once contaminated with soil or concrete on the underside, vapour barrier offcuts should not be reused as curing membranes
- Formwork release sheets — some form-facing panels incorporate a smooth plastic film to aid formwork release — this is not a curing membrane and must not be confused with builder's plastic curing sheeting
- Geotextile membranes — woven and non-woven geotextile fabrics used in drainage and waterproofing applications are not suitable as curing membranes — they do not retain moisture and allow evaporation through the fabric
Disclaimer
This page provides general technical information only. Final product selection must be confirmed against the current manufacturer technical data sheet, project specification, substrate condition, exposure classification, AS 3600 requirements, and applicator warranty conditions. Do not rely on this reference as a substitute for professional engineering or remedial building consultant advice.