How many sandwich panel fixings does your support layout require?

In the schedule, list main fastenings, system-approved stitching and flashings separately. Several proper connections to the support cannot be replaced by a larger number of small sheet screws. Each item should have a specified type, scope of application and unit of settlement.

For each panel, indicate the supports on which it is to be fixed. Then assign the number and arrangement of fasteners required for that location. The plan should account for corner zones, edges and areas of higher wind suction.

The choice depends on the facings, core, joint and substrate. In a concealed system, a strip or pressure-distributing element may also be important. The support spacing affects the force transmitted by each connection, so the number of fasteners is not selected independently of the structure.

Assume, solely to show the calculation, that the approved design specifies 18 panels, with 3 support lines per panel and 2 fixings on each of these lines. This gives 18 × 3 × 2 = 108 main fasteners. This is not the recommended number for any wall.

Assume further that the design requires one additional fastener on each of the 3 supports for the 6 edge panels. This adds 18 pieces, bringing the total to 126. The example shows how to account for zones; it does not justify the adopted scheme without calculations and verification of the specific solution.

Base flashings, corners, reveals and roof flashings have their own fixing rules. Their length, division into sections and method of forming laps are needed. The number of screws depends on the detail and the substrate, not just on the total linear metres of sheet.

Check whether the offer includes all required types of fasteners. A screw of similar length may have a different tip or washer. A well-prepared list reduces the risk that a missing type will be replaced on site with the first available item without checking its suitability.

If the gate was enlarged during the project, the number of panels and supports around it may change. The earlier screw schedule then becomes outdated, even if the total wall area has decreased only slightly. Shorter sections may require a separate arrangement of connections.

The list should therefore have a defined version consistent with the elevation drawing. Supplementing the order based on a percentage of the area alone will not show what type of fastener is needed at the new frame. Also check the substrate material: the lintel may differ from typical rails. This keeps the schedule a construction tool, not just a sum of pieces in the cost estimate.

The reserve serves work organisation and covers justified losses; it does not replace designed connections. If for the example of 126 pieces you purchase only a 5% reserve, you get 132.3 pieces and, after rounding, 133. The actual order quantity may also result from the packaging.

This should not lead to the conclusion that a five-percent reserve is the norm for every project. Determine it in line with work organisation and the availability of replenishment. For small accessories concealed in joints, a few missing pieces can stop the installation of an entire field.

The number of elements is only one criterion. Their position, type, anchoring and correct pressure must be checked. A larger number of incorrectly seated fasteners does not give an equivalent connection. The panel should not be deformed in order to pull it to the curve of the support.

In systems with concealed fixing, the check is carried out before covering with the next panel. It is worth documenting deviations and how incorrect holes were remedied. The final as-built schedule should correspond to the actual arrangement, especially if holes or panel lengths were changed.