A roof Valley occurs where a 'V' shape is formed from the meeting of two sloping roofs.

The Valley will usually contain a Valley Gutter to drain surface water (rainwater) off the roof. Constructed from sheet metal or woven shingles, the Valley is so designed to prevent the joint from leaking into the roof cavity.

Woven shingle Valleys may wear faster than those made from metal (aluminium), and as such should be inspected carefully.