Typical details

Ridge

A standard ridge detail incorporates a simple filler block (often referred to as a "Large Flute" filler) sitting over the profile, with a ridge capping flashing covering the detail. The Ridge Filler would normally be solid and sealed, however it is also possible to use a ventilated filler block and create a natural ventilation of the profile from eaves to ridge. It is important to ensure that the liner detail is correctly sealed as an air tight detail is essential in this location.

Eaves

The standard Eaves detail incorporates a filler block (often referred to as a "Small Flute" filler) sitting underneath the profile, held in place by an eaves closure flashing. The flashing and filler are designed to prevent the ingress of vermin into the built up system as well maintaining a weather tight building envelope.

Verge

The verge detail normally incorporates a simple flashing arrangement sealed to the nearest corrugation and stitched at typically 450mm centres. As it is often difficult to predict the exact location of the last sheet to be laid on a roof, the roof leg of the verge flashings is often oversized in order to ensure it reaches to a corrugation - however it is also important not to make it too large, as an unsupported leg greater than 300mm will distort and create an undesirable undulation in the flashing.

Rooflights

Triple skin GRP rooflights are normally used within a trapezoidal roof system. The liner and outer profile must provide the required non-fragility for the system, both during construction and throughout the life of the building. A clear polycarbonate intermediate layer is used to enhance the thermal performance of the rooflight system. It is normal to use rooflight closure flashings either side and top and bottom of a rooflight in order to conceal the quilt insulation. Vapour control is provided by sealing the liner in the normal way.

Roof Penetratations

Can either be small penetrations (for flues, vents, soil pipes etc) or large (for smoke vents, access hatches, dome rooflights). Small penetrations are normally dealt with by using a small bolt-on soaker unit, usually off-the-shelf systems. Large penetrations need to be carefully detailed to allow up-slope rainwater to drain around the penetration, and usually involve a bespoke soaker fabrication, or a site applied GRP weathering solution. Site welded soakers are not possible with coated steel roof systems.

Fall Arrest Systems

Inertia posts and similar fall arrest systems are easily incorporated onto trapezoidal roof systems. Many such systems do not require securing back to the structure of the building, and can attach directly to the outer sheet. Please refer to your fall arrest system supplier or speak to our technical department for our recommendations.

For more information visit our reccomended fallarrest system partners.
www.latchways.com | www.uniline.co.uk

Roof Access Hatches

As noted above, access hatches can be used with trapezoidal roof systems, however the weathering detail around the hatch needs to be carefully considered and is likely to vary from project to project.

Safety Walkways

Most trapezoidal roof systems will allow a certain amount of direct foot traffic, however for regular maintenance traffic or where significant loads may need to be carried onto the roof, it may be wise to install a safety walkway to direct maintenance foot traffic and reduce the risk of trips and falls. Please refer to your safety walkway supplier, or speak to our technical department for our recommendations.