HISTORIC IRONWORK REPAIRS IN TIMBER-FRAMED BUILDINGS.
Chapter 3
3. The Origins of Ironwork Repairs in Timber-framed Buildings. 1/2.
The great mediaeval tradition of jointing timber frames solely with pegged carpentry joints was preceded by a tradition of lower order craftsmanship that relied on using crude ironwork to reinforce the junctions of timber with timber.
Romano-british settlements, when excavated, often give up large, wrought iron staples known as 'dogs' or 'joiner's dogs' (Adkins L&R, 1988). These, (Fig 3.1) although often being identified as holdfasts for use during timber conversion were also used to bind across stress bearing paths between converging timbers. Whether they were integral to the original design or were later repairs to address problems of movement and decay is not possible to ascertain in most cases as the timbers that they joined have decayed to nothing.
Fig 3.1. Romano-british iron dogs from the excavations at College House, Braintree, Essex. Each dog is approximately 200mm in length. Another dog identical in form was found in the cellar excavations of the Tudor Great House at Cressing temple, Essex. This design clearly had great longevity.
In Saxon times ironwork was used in buildings although how still appears obfuscated. Margaret Wood in her book The English Medieval House (Wood M, 1965) quotes from the epic poem Beowulf (composed c.AD730 and written down cAD1000) that the great royal hall of Hroogar had wooden walls strengthened with bands of iron. The words iron and nail are Anglo-saxon in origin. [OE. Iren, AS] (Websters 1913). [c. AD725. Naeyl] (OED 1989).
However in England there are very few surviving timber buildings from before the 12th century and those that remain show the origins of a strong tradition in joinery rather than simple carpentry. The church at Greensted-iuxta-Ongar, Essex (Fig 3.2) dating from the 11th century is composed of riven logs rabbited (rebated) to receive planks pegged into place without recourse to ironwork.
Fig 3.2.
The log wall at Greensted Church, Greensted-iuxta-Ongar. The vertical logs
are rebated to receive planking inserts without the recourse to ironwork.
Built in the 11th century it is a rare survivor of the end of the Viking influenced
period of carpentry.
(Internet picture -
http://www.beenthere-donethat.org.uk/greensted.html).
Dendro-chronology (Tyers I, 1996) suggests that this building, unique in Britain, was built shortly after the Norman Conquest of AD1066 and already, important stone churches like that built by Cnut at Hadstock cAD1020 suggest that this was the very end of an era of Viking influenced architecture (Rodwell.W, 1974).
During the great era of mediaeval timber-framing, from the 13th to the 16th century, the use of ironwork in original build was limited solely to buildings of great status and hence complexity. For example, the great spire of Salisbury Cathedral (completed in 1315AD) is justly famous for its iron pendant that suspends the well-crafted scaffold from the iron crucifix that is the acme of this triumph of architecture.
Domestic and vernacular timber buildings were mostly fully framed, their fixings being hand-made oak pegs driven into carefully off-set holes to draw them tightly together, the frame having been proofed on the ground using drawbars, possibly of iron. The quality, design and craftsmanship of the carpentry have left scholars in no doubt that there was no inclination towards inserted ironwork in their design and this may be a factor explaining why timber-framed buildings are so over-engineered.
In mediaeval timber-framed buildings the structure was nail free except for the hundreds of small hand-made nails required to secure the laths for the tiled roofs. Thatched roofs may have been completed iron-free as the laths were tied on with bark withies, grass, flax or any other rope-like material to hand.
This is, of course, not to say that iron was not incorporated into the building at all. All the security devices, fixings and cooking equipment would have been of wrought iron. A contract between the parishioners of St Martin in Coney Street, York and Robert Giles, carpenter, made out in the year 1335 defines the requirements for a row of houses to be built. Amongst the conditions is stated:
'Windows and doors of Baltic timber board with bindings and pintles, hooks and staples, nails, locks and keys and all iron fittings well made and of consistent design.' (Salzman. LF, 1952 p430).
However, complex and sometimes ornate ironwork fixings were being used to bind the wooden joists and roof trusses into brick skinned buildings as early as the C15th. Nether Hall, Roydon, Essex (Fig. 3.3) of which all that remains is the gatehouse section of a once proud castellated and moated mansion built in 1485 illustrates this quite clearly. The timber tie-beams were fixed with large nails through pierced iron plates whose terminals anchored into the brickwork and long, wrought iron locking pins were dropped through eyelets passed into the cavity walls.
Fig. 3.3. The iron ties that once anchored the timber floors into the brickwork of Nether Hall, Roydon, Essex now dangle forlornly from the ruin. It is a testimony to the quality of the wrought iron that they are still intact over 600 years later.
Salzman in his Building in England down to 1540 makes reference to iron dogs being specifically ordered and made for repairs to timber frames; in London in 1454 - 'to Stephen Clampard for 8 dogges of iron for mending the rafters on the south of the roof, each dogge weighing 15lb.' (Salzman. LF, 1952 p291).
At Hampton Court in 1533 'Pynnes and revettes' were ordered for fastening 8 certain 'dogges of irne' weighing 164lb in the roof. (Salzman. LF, 1952 p291/309).
Salzman also makes mention of '2 iron dogges' used on the repair of the drawbridge at Gloucester Castle in 1422. Ironwork was used extensively for the fortification of window and door openings with a plethora of fittings available.
Also, although rare in this country, brickwork skins were being reinforced with so-called long ties, wrought bars of iron bridging or encasing the length and width of the walls. An idea imported from Holland it may have inspired the greater use of structural iron. Buildings of this type are prevalent in Great Yarmouth.
From the mid 18th century many timber-framed buildings underwent a series of alterations designed to bring them in line with current fashions and the contemporary needs of their occupants. Many buildings were encased or re-fronted in brick (Fig. 3.4) or even stone. Others were rendered in lime mortar and ruled with line in imitation of stonework (Fig 3.5).
Fig 3.4. Church Cottage at Hatfield Broad Oak. The 16th century frame has a brick façade planted on it dating to 1708 and excavation shows the pink rendered timber wall has been raised on a brick plinth.
Fig 3.5. The Farmhouse at Cressing Temple, Essex. Originally two separate buildings, one a granary, the timber-framed farmhouse has been rendered in lime mortar and ruled to give the appearance of stone. However, the undulating ridges and the oddly spaced windows immediately give the lie away.
