Glossary
- Jack arch
- Shallow segmental vault springing from beams, used for fireproof floors, bridge decks, etc.
- Jacobean
- The style of early 17th-century England, called after James I (reigned 1603-25), but common into the middle decades. Not always distinguishable from the preceding Elizabethan manner, with which it shares a fondness for densely applied classical ornament and symmetrical gabled façades.
Yorkshire (West Riding) - Jacobethan
- A late-19th-century coinage for the revived Elizabethan or Jacobean styles.
- Jamb
- (lit. leg): One of the vertical sides of an opening. Also (Scots) a wing or extension adjoining one side of a rectangular plan, making it into an L-, T- or Z-plan.
- Jetty
- In a timber-framed building, the projection of an upper storey beyond the storey below, made by the beams and joists of the lower storey oversailing the wall; on their outer ends is placed the sill of the walling for the storey above.
- Jib door
- A concealed door, made flush with the wall surface and treated to resemble it; sometimes spelt gib door.
- Joggle
- The joining of two stones to prevent them slipping, by a notch in one and a projection in the other; hence joggling.
- Jointed cruck
- A type of timber construction in which the main supports or blades are formed from more than one timber; the lower member may act as a wall-post; it is usually elbowed at wall-plate level and jointed just above.
- Joists
- Horizontal timbers laid in parallel to support the floor of a building.
