Dry Fix Systems for Verge, Ridge, Hip and Valley

Dry fix systems replace mortar bedding at the verge, ridge, hip and valley with mechanically fixed, purpose-designed components. They are now standard practice on UK new build housing because they are more reliable in service, faster to install, less dependent on the weather and produce fewer warranty issues across the defects period. Globe Roofing installs dry verge and dry ridge as standard on new build housing, with dry hip and dry valley systems wherever the roof design calls for them.

Dry fix is one of the core capabilities of our new build development roofing division, where every plot is fitted to manufacturer specification, photographed and signed off.

Dry verge

Verges are exposed to wind-driven uplift and rain penetration, and mortar at the exposed edge is where cracking and loose tiles begin. A dry verge system uses an interlocking unit that clips over the verge tile and is fixed back through the underlay into the rafter or batten. The profile is consistent across the scheme, the bricklayer's mortar no longer performs a structural role at the gable, and inspection is straightforward because the fixing is visible. On a housing development that uniformity carries through every plot.

Dry ridge and dry hip

The ridge is one of the most exposed parts of any roof, with wind uplift pressures at their highest along the apex. Dry ridge systems fix each ridge tile mechanically, with a continuous ventilated roll-out seal beneath, so the ridge cannot work loose as a mortar bond fails. Because ventilation is built in, the provision required under BS 5250 is delivered at the ridge in a controlled way rather than through incidental gaps, which matters on modern airtight homes. Dry hip systems secure hip tiles with dedicated brackets and fixings where two slopes meet, allowing controlled movement without the joint cracking.

Dry valley

Valleys carry water from two roof slopes and have to stay weathertight for the life of the roof. As with verge, ridge and hip, we install dry valley systems strictly in line with the manufacturer's specification as part of the approved roof system, and the detail is captured in the plot completion record alongside the rest of the roof.

Why dry systems reduce warranty exposure

The installed cost difference between wet and dry systems is small. The difference across the warranty period is not. Mortared verges and ridges generate a measurable share of warranty claims during the two-year defects period and keep deteriorating after it, as freeze-thaw cycles and heavy rain break the bedding down. Dry systems, properly installed, are largely defect-free over the same period, and warranty providers and inspectors increasingly favour mechanically fixed systems for their predictable performance. Our article on the benefits of dry roofing systems covers the comparison in full.

Make the specification explicit at tender

Where a design is silent, a contractor can default to either method, and the cheapest bid will usually price wet mortar, which becomes the developer's problem in the defects period. The practical step for a QS is to name dry verge and dry ridge in the tender documents so every return prices the same method. Where a design has not specified dry systems, we raise it at pre-start review. The detail is set out in what developers should be specifying for dry verge and dry ridge. Because dry ridge forms part of the roof's ventilation path, see also our page on roof ventilation and condensation control, and for the inspection record behind every detail, our NHBC, LABC and Premier compliance page.

Specifying verge and ridge details on a new scheme? Contact Globe Roofing, email enquiries@theglobegroup.co.uk or call 01223 890727.