Verge flashings for sandwich panel roofs: detailing the gable end

Show the roof panel thickness and its position relative to the wall on the section. Indicate the weather face, how the facing terminates and any additional supporting members. A parts list that says only “verge flashing for panel” does not tell the fabricator where or how the piece will fit.

Each leg of the flashing must cover the intended part of the edge. Too short a leg can leave part exposed; too deep a return can clash with the façade or another trim. Catalogues list different dimensions because panel edges and cladding build-ups do not all have the same section.

Do not force a finished flashing around a thicker panel. Bending it again can change the angle and shift the fixing points. Order non-standard sections to agreed dimensions. For a long run of identical pieces, check the first one against the actual roof edge before fabricating the rest.

Fix the roof panels to the frame as designed. Verge flashings have their own attachments and cannot make up for missing panel fixings. Wind action needs particular attention at the edge. The length of a trim does not determine a screw spacing that is valid for every building.

Choose fasteners for the substrate, the thicknesses being joined and the connection detail. Avoid puncturing layers that must remain sealed. List panel, trim and support fixings separately on the installation schedule so they can be checked before the edge is closed.

The straight run is only part of the verge. At the top it meets the ridge cap; at the bottom it meets the eaves flashing leading to the gutter. Draw both ends so that water flows down the roof without collecting in pockets or turning back under the cover.

The high edge of a mono-pitch roof requires its own detail; it is not the ridge of a double-pitch roof. Where a chimney flashing or service penetration is nearby, check how it changes the water path. Coordinate each junction with the roof as a whole before installation.

Verge flashings may be made from galvanised, aluminium-zinc-coated or colour-coated steel sheet. Select a finish suited to the exposure and compatible with adjoining materials. Compare a sample with both roof and wall panels: texture or gloss can look different even under the same colour code.

Identify the visible face before folding. At a projecting verge, the underside may be visible from the ground. Mark the intended face just as clearly on starter profiles, corner trims and façade cover strips so that no section of a repeated detail is folded the wrong way round.

Check the section, laps and fixings and inspect the panel edge before it is covered. Verify the seals specified for that particular junction and photograph hidden parts while they are accessible. A straight outside edge alone does not prove that the underlying layers are closed correctly.

After installation, remove swarf and remnants of protective film. Inspect the ends at the eaves, ridge and wall junctions. During later maintenance, look for distortion, coating damage and loose connections. A well-fitting flashing makes these changes easier to detect and the edge easier to repair.