Can thicker roof sheeting save on supports?

Roof cladding sheets are available in thicknesses such as 0.50, 0.60 and 0.70 mm. These are available variants, not specifications for every roof. A sheet of the same thickness with a different cross-section may behave differently. Flange widths and the number of ribs across the cover width also matter.

Going from 0.50 to 0.70 mm increases nominal steel thickness by 40%. It does not justify 40% wider support spacing. Section properties, span arrangement, applied loads and deflection limits determine the structural response.

Check bearing at the supports and the fixing points. Under wind suction the connections between sheet and structure must transfer the load. A stronger sheet cannot compensate for an inadequate fastener or base material. Check the entire load path.

Match the table to the exact profile, thickness and steel grade on order. Then check the support arrangement. A single span behaves differently from a continuous sheet across several supports. Use the column for the actual arrangement when checking the planned spacing.

The designer checks snow, wind and other required loads, as well as serviceability limits such as allowable deflection. A table value is easy to misread without its assumptions. If the seller suggests a different thickness, obtain confirmation before production that the complete selection still works.

Calculate order weight using data for the exact profile and thickness. Check whether the unit is per linear metre of sheet, per square metre of sheet or per square metre of cover. Multiply the correct unit weight by the ordered quantity, then add flashings, fasteners and the remaining roofing components.

Account for the weight difference between the two verified options in structural design and delivery planning. Record both the total load and the weight of each pack the unloading equipment must handle. A thicker sheet may resist minor deformation better but still requires proper lifting. Its thickness gives no general permission to walk on the roof or place loads between supports.

Compare two verified combinations of profile, sheet thickness and support layout. Include purlins or battens, fasteners and labour. If thicker sheeting permits a different structure, quantify the saving using design calculations and actual material quantities.

With an existing substructure, removing supports calls for a separate assessment and may yield no saving. Sometimes the surcharge improves a particular property while the spacing stays the same. Establish what performance you are paying for.

Include the support connections and how they bear on the primary structure. Fewer supports may concentrate forces at the remaining points. Include any resulting changes confirmed by the structural designer in the estimate.

Specify the full profile designation, thickness, steel grade, coating and configuration used for design. Attach the agreed lengths and fixings list. Avoid unspecified substitutions with “similar” sheeting. Equal rib height does not guarantee equal properties.

Before installation, compare support spacing and bearing width with the drawings. Check condition and alignment in one plane. Resolve discrepancies before covering the structure. Choosing thicker sheeting afterwards cannot replace checking the whole design. An early check can prevent expensive dismantling.