Glossary - external shape
Gabled - see gable.
A ridged roof which finishes at each end on a gable.
Gambrel - a ridged roof finishing at each end on a small vertical gable below which the
roof slopes to meet the gable wall.
Half-hipped - a ridged roof finishing at a gable of which a small section of the top part is
angled or hipped, the rest vertical. In effect the opposite of gambrel. See jerkin head
Helm - a four sided roof, rising to a point, and sitting on four gabled walls.
Hipped - where the ends of the roof are sloped rather than vertical. see piended
Lean to - a roof with one slope only, built against a vertical wall.
Mansard - a roof with a double slope in which the top part is shallower.
Pavillion roof - a roof that is hipped at both ends.
Pitched roof - refers to almost any roof built at an angle, the pitch refers to the slope of
the roof.
Structural components
Ashlar piece - a short vertical timber which runs down the inner face of the wallhead. It is morticed into
a rafter at a point near its foot, and is also usually connected to the rafter by a timber spanning the
wallhead, which effectively forms a timber triangle. The ashler post, in pressing against the wallhead,
prevents the roof from spreading outwards.(rather confusingly it has nothing to do with ashlar stonework) (illustration).
Braces - pieces of reinforcing timbers set diagonally between structural members. An
arched brace comprises two curved timbers forming an arch.
Collar beam - a horizontal timber which ties rafters together at a height above the wall
plate, ie above the level of a tie beam.
Crown post - a vertical post standing on the centre of a tie beam and supporting a collar beam.
Hammerbeam roof - a hammerbeam is a horizontal timber projecting at wall head level
towards the centre of the roofspace, like a tie beam without a central section. Supported
on corbels, they carry a vertical timber, the hammer post, which supports a purlin, and is
usually braced to a collar beam.
King post - a vertical timber rising from the centre of a tie beam to support the ridge.
Principals - the main inclined timbers in a roof.
Purlin - a continuous horizontal timber running parallel to the ridge, sometimes referred to as side timbers.
Queen post - a pair of vertical timbers rising from a tie beam to support purlins.
Rafter - a timber sloping from the ridge to the wall head and supporting the roof
coverings. An angle rafter
supports hip ends.(illustration).
Ridge - the line formed where two sides of a sloping or pitched roof meet. The ridge piece is a main timber running along the apex of the roof.
Sprocket - a short timber placed at the foot of a rafter to project over the wall head.
Tie beam - a horizontal beam which joins the feet of the principals at wall head level.
Truss - name given to rigid frame of principals and tie beams or collar beams.
Wall plate - a timber laid along the top of a wall, rafter ends and studs and posts from
below may be joined to it.
