The hip ridge detail

By - , Build 77

Here’s a simple way to make your ridge junctions neat and tidy.

A neat ridge but lack of underflashing led to leaks at the joints.
A neat ridge but lack of underflashing led to leaks at the joints.

The flashing of a hip-roof ridge junction, especially with aluminium zinc-alloy-coated roofing or pre-coated corrugated roofing, is one of the most difficult to achieve neatly, and to make waterproof. With the advent of aluminium zinc-alloy coatings, roofers and plumbers have put away their soldering irons and come to rely on lapped joints and sealant.

A neat weathertight detail is possible by providing a simple underflashing, which does the work of weatherproofing/water shedding. Neat workmanship for appearance is then the only requirement for the hip/ridge capping.

Step 1

Fit the roofing as normal, putting roofing underlay under the join using normal clearances.

Step 2

Lay a zinc, aluminium or butyl rubber underflashing (about 600 × 300 mm) over the ridge junction and fold centrally over the join.

Step 3

Bend the flashing down to match the roof slopes, gather excess material into a pleat and fold down to lie flat.

Step 4

Lay hip ridges, lapping or cutting on an angle (mitre) to butt together. Trim underflashing to fit under hip ridges and fix ridge flashings to hip, dressing down soft edges.

Step 5

Fit central ridge to form tight fit to hip ridges. Fix in place and dress down soft edge.

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Articles are correct at the time of publication but may have since become outdated.

A neat ridge but lack of underflashing led to leaks at the joints.

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