Btu British thermal unit (replaced by kilowatt)

Casement The hinged and opening part of a window

Cavity closer Fitting or method of closing the cavity wall at peripheries of openings

Cavity tray A tray-shaped damp-proof course installed to cavity walls over a junction with the roof

Close-boarded roofs Where the rafters are clad tile side with timber boarding

Cappings Finishing pieces to cover joints and ends

Cold roof A roof that is insulated between the rafters or below them

Coping Weathering stone or course to the top of a wall

Corbelling Successive course-projecting brickwork

Crack vent Window casement stay that keeps it slightly ajar

Cresting Ornate ridge detail on a roof

Derating Allowing for insulation overheating in electric cables

Dessication Dried out subsoil causing shrinkage and subsidence

Dentil course Projecting course of stone or brick

DPM Damp-proof membrane beneath the base or slab finish

Dummy bars Fake glazing bars in windows (sometimes between the panes of double-glazing)

Eaves The lower edge of the roof

Fascia A horizontal decorative board fixed horizontally along the eaves to finish the roof edge

Fenestration Architecture of windows

Fielded panels Decorative relief work on wall panels

Finials Pointed ornaments on a gable end of a roof ridge

Flashings Weathering between roof sheeting and wall

Flemish bond Brick bond of alternate headers and stretchers in each course

Fletton Cheap brick

Glazing bars Slender sections used to support glass or plastic in windows or roofs

Header The end face of a brick

Horns Projection on the cill of a window or door frame to help build it into a wall

Joist A horizontal structural member of a floor or ceiling

Lead code The grade (thickness) of lead

Lead rolls Wood core rolls dressed with lead

Loop-in circuits Lighting circuit to reduce T-joints using ceiling roses

Low-e glass Low-emissivity (reflective) coated double glazing

Noggin A small piece of timber used between other main structural timbers to stiffen them

Parapet A low wall on the edge of a roof, balcony or gutter

Pitch The angle of a roof or rafters

Quoin Brick or stone set in the corner of a wall

Racking The result of wind pressure, causing a conservatory to lean

Radial circuits A spur circuit leading off a ring circuit without looping back

Rafters The sloping sections of a roof that support the glazing bars or tile battens

Rapid ventilation By a window or door opening vent or an electric fan

Ridge The apex of a roof

SAP rating Standard Assessment Procedure figure for valuing the energy efficiency of a dwelling

Snap header A half-brick (not a header)

Solvent-weld plumbing Glued permanent joints of plastic pipe

Stucco Smooth external plastering

Spalling Frost damage to bricks

Soakaway A large hole or chamber for draining rainwater into the ground away from the building

Soakers Undertile weatherings

Solar gain Extent of potential additional heating caused by the sun

Stretcher The long face of a brick

Terrazzo Coloured floor mosaic

Tie bar Steel bar between opposing walls or roof slopes installed to prevent them spreading apart

Tusk tenon Small tenon joint (often used on stairwell trimmer to trimming joists)

Trickle vent Background vent that can be left open and is secure

TRV Thermostatic radiator valve controlling radiator temperature

U value A measure of thermal transmittance through an element

Vertical DPC Damp-proof course incorporated within cavity closer

Verge The edge of a roof along the gable end

Voussoir A wedge-shaped arch brick

Warm roof A roof that is insulated on the top rather than between the rafters or below them

Wind post A vertical metal post incorporated within a wall structure to resist wind pressure

Y junction A y-shaped drainage piece for joining one run to another