A custom flashing can look simple once it has been folded. Reaching that point, however, depends on the fabricator receiving enough information to understand exactly what the finished profile needs to do.
A quick sketch may be sufficient for a basic fold. On a more detailed junction, one missing measurement, an unclear angle or a reversed orientation can delay production and create unnecessary questions between the office, workshop and site.
For relevant housing work, the National Construction Code’s sheet roofing rules require roof flashings and cappings to be purpose-made, machine-folded sections compatible with the surrounding roofing materials. A clear profile drawing helps translate that requirement into a product the fabricator can confidently manufacture.
Start with the installed position
A useful drawing should show how the flashing will sit once it reaches the building.
Marking the roof side, wall side, visible face or direction of water flow gives the fabricator context that the cross-sectional shape may not provide on its own.
This becomes particularly important when a profile contains similar-looking legs or when left-hand and right-hand versions are required. A simple note such as “outside”, “up” or “towards roof” can prevent the drawing from being interpreted in reverse.
The name used for the profile should also be descriptive. Informal names that make sense to one site team may mean something different to another person.
Show every important dimension
Each leg, fold, return, hem, kick or drip edge should be dimensioned clearly.
Where a fold is not intended to be 90 degrees, show the required angle rather than leaving it to assumption. The dimensions should also make sense when considered together. If the individual legs do not align with the overall girth, the fabricator may need clarification before production can begin.
The order should state the required lengths and quantities as well. A profile may be accurate in cross-section but still create problems if the length, number of pieces or preferred joint locations have not been considered.
Where different sections of the project require slightly different profiles, identify each variation separately rather than attempting to explain several versions on one crowded sketch.
Identify the material and finish
The profile shape is only one part of the specification. The order should also state the material, thickness, finish and colour.
Where COLORBOND® steel is required, include the complete product and colour information rather than relying on an informal description such as “grey” or “dark roof colour”.
The adjoining materials also need to be considered. BlueScope’s guidance on compatible metals explains that direct contact with, or water run-off from, certain metals can contribute to accelerated corrosion of COLORBOND® steel.
The fabricator may not have control over the broader building detail, but identifying the intended application can help bring an obvious material conflict to the project team’s attention before the flashing is made.
Explain unusual folds
Some profile details are difficult to communicate through measurements alone.
A small return may be intended to form a drip edge. A hem may stiffen an exposed edge or improve its finished appearance. Another fold may provide clearance around cladding, masonry or a roofing component.
A short note explaining the purpose of an unusual detail can help the fabricator recognise when something in the drawing appears inconsistent.
Photographs are also useful. A wide image can show where the flashing belongs, while a close-up can reveal the junction, existing profile or obstruction the drawing is intended to address.
Photos should support accurate measurements, not replace them.
Complete a final check
Before submitting the order, confirm that:
- The installed orientation is obvious
- Every important leg and angle is shown
- Left-hand and right-hand versions are identified
- Material, thickness, finish and colour are stated
- Lengths and quantities are included
- Visible faces are marked where appearance matters
- The drawing has a date or revision number
- Any photographs match the current drawing
This review may take only a few minutes, but it can prevent delays and avoidable site adjustments.
Do not assume an old profile will still fit
An existing flashing can provide a useful reference, but it may have been bent during removal, modified during installation or manufactured for a slightly different junction.
Likewise, a drawing from an earlier stage should not automatically be reused without checking the current site. Even repeated building designs can contain variations in framing, cladding thickness, roof pitch and adjoining materials.
The strongest profile drawings are not necessarily the most elaborate. They are complete, legible and difficult to misinterpret.
PPC Flashings manufactures custom profiles for residential, commercial and industrial projects across Melbourne and Victoria. Clear measurements, useful site context and an identifiable drawing revision give the workshop a smoother path from the initial request to a flashing that is ready for its intended application.
The information contained in this news post is provided by way of general information only and has not been prepared with your specific needs in mind. Before application in a particular situation, we recommend that you obtain expert advice confirming the suitability of the services and/or products and information in question for the application proposed.