D

Dado
The lower part of an internal wall, below chair-rail height, when decorated differently from the upper part.

Damp Proof Course
A layer of impervious material placed in a masonry wall or at floor and wall junctions to prevent migration of moisture.

Datum Point
Any reference point of known coordinates from which calculations, measurements, distances and ground levels may be taken. It is a reference point used by surveyors and engineers and is usually marked on the site plan.

Decking
A horizontal boarding or forming a cover for a deck. Can also be used for Formwork.

Defects Liability Period
A specified period of time by which the contractor is obligated to carry out rectification work of defects arising from faulty workmanship and/or materials at their own cost.

Dentils
A decorative row of small blocks like teeth along the cornice or fascia.

Detached Pier
A stand alone pier acting as a support for floor beams.

Detention Tank
A tank constructed for the temporary storage of peak run off storm water flows.

Diffuser
A device used to scatter light in order to reduce glare.

Door Frame
A timber or metal frame which surrounds and supports the door.

Door Furniture
All accessories used in and for doors. Hinges, handles, locks, bolts, latches, door stops, push plates, etc.

Door Jamb
Vertical sides of a door frame.

Dormer
A window with a small roof and sides projecting from a larger sloping roof.

Double Glazed
A form of glazing consisting of two panes of glass with a void space between them used for thermal and sound insulation.

Double Hung Window
A window with two sashes vertically sliding..

Dove-tail
A neat joint between two timbers, the wedge-shaped projections along one edge slotting into the same shaped sockets of the other.

Down Light
A small light fixture which concentrates light beams mainly downward.

Downpipe
A metal or plastic pipe for rainwater, from a roof or gutter to a stormwater drain.

Drainage Pit
Built in-ground structure, to collect or redirect drainge water.

Drainage Plan
A plan of drainage network with a building outline.

Dwarf Partition (Wall)
A small wall which does not carry through to the ceiling.