Which sandwich panel installation mistakes can you prevent before delivery?

Before delivery, carry out a check measurement of openings, diagonals and heights. Record the deviations and agree the method of rectifying them with the person responsible for the structure. If components are to be ordered to size, do not base the cutting plan solely on an old drawing. Confirming the dimensions on site protects against cutting the entire batch.

Determine the method of unloading for the length and weight of the packs. Provide a level storage area and supports arranged according to the instructions. A long pack must not be treated as a rigid beam that can be supported at will. The transport packaging is also not permission to store the material in water.

On receipt, inspect the corners, edges and facings. Damage to the interlock can hinder a correct connection even when most of the surface looks good. Mark defective components and assess them before carrying them onto the roof. Laying a damaged panel in the hope that the next one will cover it usually postpones the problem.

The first panel sets the direction for the subsequent ones. Check its alignment relative to the supports, the eaves or the corner. After laying several components, measure the line of the joints again. A small deviation repeated across the whole wall can produce a large error at the last field.

Do not choose the number of screws according to habit from a previous build. The pattern depends on the design, the loads and the zone of the building envelope. The support and the correct fastener also matter. Overtightening can deform the sheet and the seal. Undertightening does not give the correct compression. The correct tool setting is checked as work proceeds.

Connections should be made in the order specified for the chosen system. Some seals must be laid before the next panel is pushed into place. Later access may no longer be possible. The visible sealant bead at the edge alone does not confirm that all required layers have been installed inside.

Set inspection points at upstands, corners and service penetrations. Check the continuity of seals and the condition of the substrate. Tape will not bond correctly to a dirty or wet surface if the conditions of use do not permit it. A photo taken before fitting the flashing helps later to reconstruct how the detail was executed.

Use tools recommended for panels and coated sheet metal for cutting. Grinding with a cutting disc can overheat the edge and scatter hot particles over the cladding. Cutting an opening must also preserve the required support. A large service penetration is not just a job for someone with a saw.

Remove swarf immediately with a soft brush or another permitted method. Do not wait until the final roof cleaning. Leftover particles can corrode and leave marks on the coating. Remove protective films within the period specified for the delivery. Prolonged exposure to sunlight can make them difficult to remove without adhesive residue.

A single inspection after the entire enclosure is complete will not reveal concealed joints. It is better to define several simple stages. This way a defect concerns only a small section, and the crew still remembers the execution conditions. Acceptance should cover both appearance and conformity with the agreed solution.

• Before installation: measurement and condition of supports.
• After the first panels: direction, pressure and connections.
• Before flashings: seals and insulation terminations.
• At the end: fixings, cleanliness and free drainage.

Also record the places requiring correction and the deadline for their rectification. When other crews return to the finished roof, pass on the rules for access and surface protection.