HISTORIC IRONWORK REPAIRS IN TIMBER-FRAMED BUILDINGS.

Chapter 5.

5. Types of iron ties. 5/6.

5.12 Pin-ties.
Round headed pins whose shanks are pierced for nails and the tip nibbed for a staple. Used by passing through a bored hole and then fixing in place. Unusual but undoubtedly contemporary with threaded bolts. (Fig. 5.29 - 5.30).

Fig. 5.29. A pin-tie in the south-east corner of the Wheat Barn at Cressing Temple. It has the rounded head of a forelock bolt but is paired with a threaded draw-tie on the north-east corner. It may be a one-off and a classic example of re-use (of a forelock bolt shank).

Fig. 5.30. A threaded draw-tie on the north-east corner of the Wheat Barn at Cressing Temple. A contemporary repair to the pin-tie incorporating the same design strategy with the added advantage that the joint can be drawn carefully together using the thread.

5.13 Tie rods and tie bars.
Tie rods and bars are used to connect distant members and to arrest their relative movement. A distinction is here drawn between rods, which are of round section, and bars that are of square or other polygonal section. Tie rods and bars can be anchored in a number of ways including threaded nuts, (Fig. 5.31) nailed and stapled terminals (Fig. 5.32) or forelocks (Fig. 5 33). Also split cotters may be used.

Fig. 5.31. A tie-rod passing through a main tie-beam in the Granary at Cressing Temple. The lower end is threaded with a square nut, a pressure plate and a wooden spacer. The other end is nailed onto a collar. It is one of a pair designed to arrest the racking of the butt purlin roof. See Fig. 5.32.

Fig. 5.32. A second tie-rod in the Granary at Cressing Temple. This one has been fitted the other way up with its nailed and stapled terminal downmost. There is evidence that it was designed to run parallel to its partner (from tie to collar) but that this strategy failed and it was repositioned.

Fig. 5.33. A tie-bar fastened with a forelock against an S-plate at Sible Hedingham Church, Essex. The terminals of such bars are not normally visible on timber-framed buildings as they are usually buried in the external render. The heavy forging denotes a date no earlier than the Tudor period (when the aisle was erected).

Tie rods can be joined with links or turnbuckles (Fig. 5.34) to make their fitting and adjustments easier. Their ends may also pass through, or be joined to, terminal plates in the shape of an X, an S, (Fig. 5.35) or a simple plate (Fig. 5.36). Round terminal plates are normally called bosses whilst the term pattress plate is currently used for all types of terminal plate. By the early 1800's, tie-rods were being designed into all sorts of industrial buildings as well as other commonplace installations like bread ovens. Very short tie-rods are sometimes called stays (Fig 5.37).

Fig. 5.34. Turnbuckle in the bell-frame of St Osyth Church, Essex. Turnbuckles like these were common by the late 1800's and facilitated a far more precise range of adjustment.

Fig. 5.35. Two S-plates. The first is 20th century, machine made and drilled. Its regularity alone gives away its modernity. The second is 19th century, hand forged and with a tang in its centre to receive the tie-rod or bar. The thin tang could be passed easily through a gap in the frame or the joints in a brick wall.

Fig. 5.36. A modern boss with a tie-rod secured with a hex-head nut in a timber-framed building in Lavenham, Suffolk. An unobtrusive repair that is barely visible on the street.

Fig 5.37. A very short tie-rod known as a stay. Used to pin two frames together this one dates from the late 19th century and was used at Ashes Farm, Cressing, Essex.

5.14 Threaded bolts, 5.15 Stirrups and 5.16 Composite ties.