Scaffold Sheeting Calculator — Monofilament & Netting Quantities

Monofilament sheeting is a woven fabric that is largely windproof (70-90% wind reduction). It contains dust and provides weather protection but creates very high wind loads on the scaffold — requiring intensified ties. Debris netting is a coarser mesh that catches falling debris but allows wind through (50% wind reduction). It creates less additional wind load.

Cladding a scaffold sharply raises its wind load — NASC TG20 uses a force coefficient of 1.30 for a fully clad/sheeted scaffold, far above an open structure, so a sheeted scaffold needs many more ties and may need stronger standards or extra bracing. For a fully sheeted independent scaffold, TG20:21 limits the tie pattern to roughly one tie per 9.0 m², with a maximum of 3.0m vertically (tied at every lift) and 4.0m horizontally. This calculator defaults to a deliberately conservative 2.5m × 2.5m grid (about 6 m² per tie); the actual pattern must come from a TG20 compliance sheet or a bespoke design — always confirm with your scaffold designer before sheeting.

Sheeting is fixed with elastic bungee toggle ties (hooked elasticated cords) threaded through the reinforced eyelets and clipped to the scaffold tubes. The ties themselves should meet BS 7955 for tensile and eyelet/fastener strength, but the standard does not set a per-square-metre count — fixing density follows the manufacturer's installation instructions. Typical fixing centres are 300-600mm around each sheet perimeter and along the laps, tightening to about 200-400mm in high-wind or perimeter zones. A common installer rule-of-thumb is a minimum of one tie per square metre, so this calculator allows at least one bungee per m² of sheet area as a conservative floor — order more for exposed sites and follow the sheeting maker's instructions. Sheets are overlapped externally by 150-300mm and secured with extra bungees at the lap, and the bottom edge must be fixed down to stop billowing. Cable ties should NOT be used as primary fixings.

Use monofilament sheeting when: weather protection is needed (painting, decorating), dust containment is required (demolition, abrasive blasting), or the client wants to hide the works. Use debris netting when: only debris catch is needed (general construction), wind load must be minimised, or the scaffold is in an exposed location.

Sheeted scaffolds should be inspected before and after high winds, and a competent person should be named (in line with NASC SG46:24 Adverse and Inclement Weather Conditions) with authority to suspend work and release or remove sheeting. There is no single universal trigger speed — the threshold comes from the scaffold design or the contractor's risk assessment. As a guide, HSE notes balance and safety are affected from about Beaufort force 5 (≈23 mph), and a common stop-work limit is around 40 mph (≈18 m/s); 38 mph equals 17 m/s. Some sheeting has wind-release panels that open under load. Never assume sheeting can withstand storm-force winds — the extra load could cause scaffold failure.