Roofing quotes are written in a vocabulary nobody teaches you, and the difference between a quote for a ridge and one for a verge is a few hundred words of jargon away from being obvious. This is the anatomy of an ordinary British pitched roof, from the top down, in the words a contractor will use.
The structure underneath: names of roof parts you cannot see
Rafters are the sloping timbers running from the ridge down to the wall. A purlin is a horizontal beam partway down supporting them on a traditional cut roof. A trussed rafter roof, standard since the 1960s, replaces cut rafters and purlins with factory made triangulated trusses, which is why modern lofts are full of diagonal timbers and older ones are open. The wall plate is the timber along the top of the wall that the rafters sit on, and joists span across at ceiling level.
Parts of a house roof: the lines at the top and the edges
The ridge is the horizontal line at the apex. A hip is an external sloping edge where two roof planes meet going down, and a valley is the internal angle where they meet going up. The verge is the edge of the roof at a gable wall, where the tiles stop; the eaves are the lower edge over the wall, where the gutter is. A gable is the triangular section of wall under a roof that ends in a vertical face rather than a hip.
Roof components: the covering and what is under it
Tiles or slates are the visible covering and they shed most of the water. Battens are the horizontal timbers they hook or nail onto. Underlay, sometimes called sarking felt, sits beneath the battens as a secondary barrier catching wind driven rain and carrying it to the gutter. On some older Scottish and northern roofs, sarking is boarding rather than a membrane. Flashings are the metal, usually lead, that weathers a junction such as a chimney or an abutting wall.
The edges you can see from the ground
The fascia is the board across the rafter ends carrying the gutter. The soffit closes the underside between the fascia and the wall and usually carries the eaves ventilation. A bargeboard does the fascia's job at a gable verge. Those three are what most people are looking at when they say the roofline needs doing, and they are maintenance items rather than structure.
Roof names by shape, from gable to a cottage roof, and pitch
Pitch is the angle of the slope, and it is not decorative: every covering has a minimum pitch it is certified to, which is why a slate cannot be laid at the angle a profiled interlocking tile can. A gable roof has two slopes and vertical ends. A hipped roof slopes on all four sides. A mansard has two pitches with the lower one near vertical. A Dutch barn or gambrel roof similarly breaks the slope but keeps gable ends. A cottage roof usually means a steep pitch with a low eaves and small dormers, which is a description rather than a defined type.
Questions people ask about parts of a roof UK
What is the difference between a hip and a valley?
A hip is an external sloping edge where two roof planes meet going down; a valley is the internal angle where they meet going up and water collects. Valleys are lined and are where leaks concentrate.
What is the difference between a verge and eaves?
The verge is the roof edge at a gable wall; the eaves are the lower edge over the wall where the gutter hangs.
What is sarking?
The layer beneath the battens. In most of the UK it means the underlay membrane; in Scotland and parts of the north it often means timber boarding across the rafters.
Does roof pitch matter for the covering?
A great deal. Every covering has a minimum pitch it is certified for, and laying below it is a leak by design rather than bad luck.