Composite slate roof on a many-valleyed house in the British Properties

A complicated roofline re-roofed in composite slate, with the valleys planned before the first tile.

Neighbourhood: British Properties
Roof: composite, dark grey
Product: Cascade Shingle Co.
Size: 4,200 sq ft
Time on site: 14 days
Finished: 2026-06-24

Close view of overlapping grey shingles with a seam running diagonally across the roof slope — During Valley flashing before the shingles went over it

Aerial view of a residential roof with several valleys, dormers and chimneys covered in grey shingles — Three quarter view of the finished roof

What the roof was like

A large house with several valleys, hips and dormers and an older roof that had been patched repeatedly at the valleys.

What made it hard

More than half of the old leaks were at valleys where two slopes met at awkward angles. The tile layout had to land cleanly at every hip and dormer.

What we installed, and why

We drew the layout of every valley and hip on the deck before ordering, installed open metal valleys with a high temperature underlayment and laid composite slate in courses that meet each hip cleanly.

The result

The valleys, which were the source of the old leaks, are now the most carefully detailed part of the roof. The owners received a photo record of each valley before it was covered.

Composite and synthetic roofing Composite slate More work in British Properties