Matching the flashing finish to the facing of a sandwich panel

Aluzinc denotes a different type of metallic coating. It is not a name for aluminium sheet or coloured paint. When comparing offers, you therefore need to read the full material description. The word steel alone does not yet say what protection is present on both sides of the finished component.

Ridge caps work at the top of the roof, while starter profiles are at the lower part of the wall. Gutter aprons regularly come into contact with running water. Flashings inside the hall may in turn be exposed to conditions associated with the business activity. This does not always justify an identical choice of coating in every zone.

The specification should be linked to the actual environment. It is worth taking into account moisture, dirt and the method of cleaning the surface. Recommendations for an ordinary façade should not be transferred to a room with a different purpose without checking the data. The answer should follow from the material documentation.

Two flashings in the same colour may differ in gloss and structure. On a long façade such a difference is often more visible than on a small sample. Before ordering, it is therefore worth comparing the material in similar light. Both the hue and the character of the reflection are assessed.

Verge flashings and corners are often viewed from a different angle than a flat wall. This additionally affects the perception of colour. Conformity should not be assessed solely on the basis of phone photos. When aesthetics matter a great deal, samples should correspond to the finish actually being ordered.

The cover flashing and the mounting profile do not have to be made from the same sheet thickness. In catalogues, starters are listed separately from thin verge trims or cover trims. A change in thickness can also affect whether a particular bend can be achieved. It is worth establishing this before preparing the cross-section.

However, it cannot be assumed as a simple rule that a thicker sheet will always improve any detail. It may change the way it connects to the panel, require a different tool, or make the intended installation more difficult. The selection must be related to the function of the element. It should not be an arbitrary upgrade to the ordered solution.

The drawing of the flashing must indicate on which side the intended finish is located. This matters for asymmetrical cross-sections. Incorrect reversal of the colour may require the element to be remade. It is not always possible to solve the problem by rotating the finished trim.

The concealed surface also requires proper specification. It should not be assumed that lack of visibility allows its specification to be omitted. This applies in particular to flashings at damp contacts and connections with other materials. The contact conditions should be known to the person selecting the entire system.

Galvanised, aluzinc and coated sheets must be protected against damage during transport and on-site processing. Sliding one element over another may leave scratches. It is worth unpacking the flashings in a place that allows them to be set down without contact with sharp waste.

Cutting with an abrasive disc is an unsuitable method for cutting such flashings. Tools designed to work without overheating the edges are used. After drilling, swarf must be removed. Damage should be assessed according to the recommendations for the specific coating, rather than covered with arbitrary paint.

For each group of elements, the material type, thickness, finish and colour side are recorded. This makes it easier to check the delivery of ridge caps, verge flashings and chimney flashings. Non-standard sheet metal flashings should have the same accuracy of description as catalogue elements. A drawing alone without the material is incomplete.

At acceptance, the markings are compared with the order and the surfaces are inspected. Any change of material must be clarified before the element is installed. This is easier than assessing differences after the roof is completed. Consistent documentation also helps to determine the later method of cleaning and maintenance.