doors cost guide
Bi-fold Door Options
January 9, 2017
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glossary

Glossary of Terms


  • UPVC – unplasticicised poly vinyl chloride (or vinyl)
  • Composite – PVC, Wood & GRP combined
  • GRP – glass reinforced plastic (Fibreglass) similar to car bumpers
  • Profile – the design of the frames (thickness etc)
  • Air Gap – the distance between the panes of glass in a double glazed window (from 6mm to over 20mm). The wider the more energy efficient.
  • Threshold – the bottom of the door (raised or flush)
  • Furniture – handles, letter boxes etc.
  • Low-emissivity (low-e) – metal oxide coated energy efficient glass
  • Gas filled units – some double glazed unit air gaps can be filled with an inert gas (such as Argon) to help improve energy efficiency
  • Solar Gain – usually mentioned when the glazing can keep you warm in winter, cool in summer.
  • Safety Glass – usually heat treated & tempered to break safely into very small pieces. Should always be used for glazing that reaches ground level.
  • Head – the top of the door

Glossary of Terms


  • Standard door size – 6 feet 6 inches high x 2 foot 6 inches wide (1981 x 762mm)
  • Non-standard is usually just wider not higher (2 ft 9 ins wide or 838mm)
  • NFR – non fire rated door
  • FD – fire rated door (FD30 last 30 mins / FD60 last 60 mins)
  • Beading (beads) – these are the flitting that hold in the door panels or glazing (used to be putty in old wooden windows)
  • Core – the internal materials for the door itself
  • Handing – for a pair of doors it refers to which door opens first
  • Lights – the glass. Example = top light is a glazed panel at the top of the doors
  • Veneer – a very thin layer of material that is the surface finish
  • Wood grain – a surface finish that mimics the appearance and feel of real wood
  • Side Panel – an additional panel used for oversize openings
  • Door Jamb – the vertical sides of the door frames