HISTORIC IRONWORK REPAIRS IN TIMBER-FRAMED BUILDINGS.

List of Figures.

Chapter 1.

Fig.1.1. This figure is given to show how historic ironwork is ignored in record drawings. The photograph clearly shows a series of L-ties securing the tie-beams yet this detail has not made it onto the record drawing. Sadly, this is normal.

Fig 1.2. J.Ray Harrisons' elegant drawings made from photographs produce a true record of the barn at Acol Farm, Kent albeit from its remnants. Drawings like these could serve as the basis for a closer typology.

Fig.1.3. A dovetailed cheekpiece on the arcade post of the Barley Barn at Cressing Temple. Originally pegged with trenails, its clumsy form has been reinforced with large wrought iron spikes. Repairs like this require the removal of timber from the arcade post and are subject to the same weaknesses that destroyed the original tenon. The two great barns at Cressing Temple bear the scars of all the failed timber patch repairs. Compare it with Fig.1.4 below.

Fig 1.4. A stapled L-tie also on an arcade post in the Barley Barn at Cressing Temple. Its neat, slender design does not draw the eye like the heavy timber insertions above it. Vernacular farm buildings offer the easiest study of ironwork repairs, which in domestic situations are almost always buried in the décor.

Fig 1.5. An arcade post in the Wheat Barn at Cressing Temple. The forged terminal of an L-tie which has superseded a nailed on timber cheek piece. The broken off nails are clearly visible and the ghost of the removed timber can just be discerned in this photograph.

Chapter 2.

Fig.2.1. Truss 5 of the Wheat Barn at Cressing Temple illustrating the weaknesses associated with a post-head. The dovetail on the underside of the tie beam has broken its peg and jumped out of its matrix. The upstand has been forced to shear off along its grain and was slowly twisting out. The notched lap joint on the diagonal passing brace has also broken its peg and has been nailed. The entire movement has been arrested by a single, slender, wrought iron tie. Almost certainly an early Victorian intervention as part of a large scale repair phase. This truss was the subject of a movement study for this dissertation.

Fig.2.2. Truss 3 of the Barley Barn at Cressing Temple. The remodelled barn has walls dating to c.1400Ad. The forelock bolt is one of a series inserted to prevent the jowled posts from further splitting out. An additional L-tie has been added to prevent the tie beam from lifting out of its dovetailed joint.

Fig 2.3. A photograph taken by John McCann for Cecil Hewitt in the roof of Harlowbury. The scarf joint is shown heavily strapped (just above the scale) and a large L-tie reconnects the tie beam to the top plate. This photo was found in a sheaf of loose papers and has never been published.

Fig 2.4. A clamp placed parallel to a failing top plate in the Granary at Cressing Temple. The plate is bowing outwards under the pressure of the roof. The clamp is secured in place with forelock bolts whose round heads set them apart from threaded bolts.

Fig 2.5. A clamp reinforcing a failed scarf joint in the Wheat Barn at Cressing Temple held in place with square headed bolts and nuts. Compare with Fig.2.6 below.

Fig 2.6. The failed scarf hidden under the eaves. This is a splayed and tabled scarf with under-squinted butts and a wedge key. An extremely complicated joint and not prone to early internal failure this joint dates to c.1260AD. The threaded bolts indicate a post 17th century repair.

Fig 2.7. A simple strap repair nailed and stapled across an edge halved and bridled scarf joint in the top plate of the north wall of the Barley Barn at Cressing Temple. The pegs have rotted away.

Fig 2.8. A modern fish-plate reinforcing a failing top-plate in the Barley barn at Cressing Temple. Inserted in 1989 as part of the post 1987/ 89 gale damage repairs, this ugly intervention was supposed to be temporary. Plates of this dimension with hex headed bolts all date to the late 20th century.

Fig. 2.9. The interior of the Granary at Cressing Temple. The pegs in the butt purlin roof have all loosened over the years since it was erected in 1623. The building has badly racked and successive iron tie rods have been inserted to arrest the movement. Historic removal of three of the original roof dormers may have been to address this problem.

Fig.2.10. A cracked beam in The Rectory, Kelvedon Hatch. The calamitous failure was caused by its proximity to a powerful modern stove which, over a period of 20 years, heated and cooled the timber to beyond its endurance.

Fig 2.11. A tableau in the Wheat Barn at Cressing Temple shows how the barn was originally walled with vertical boards. Around 1620 AD the walls were completely dismantled and infilled with brick nogging. A significant amount of ironwork was then introduced to arrest the subsequent movement.

Fig 2.12. Dry rot is visible in this sole plate in the Wheat Barn at Cressing Temple. Its cause is both rising damp and an ineffective gutter system which vented onto the ground. Remedial work included re-routing the drainage and lowering the exterior ground level.

Fig. 2.13. The corner of the porch of the Wheat Barn at Cressing Temple. The timbers have been exposed to water and animal erosion. The yard contained long-horn cattle who enjoyed licking the sodden timber. This eroded the woodwork far quicker than normal.

Fig. 2.14. An extreme example of low caste workmanship in Forge House at Castle Camps, Cambs. This pseudo-cruck constructed door frame with every scantling pinned in with wrought-iron nails gives an idea of the type of work prevalent from the early 1700's.

Fig 2.15. The Wheelwrights Cottage at Castle Camps, Cambs. The insertion of a floor with dormers into a thatched cottage which was probably originally a kitchen to a bigger house was potentially a disaster. Copious ironwork was amateurishly inserted to arrest its collapsing floors and splaying walls.

Chapter 3.

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.

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).

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.

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.

Fig. 3.6. The striking façade of 25 High Street, Thaxted, Essex. The poor quality timber-frame with its multitude of alterations was not meant to be seen. The building would have been rendered with lime plaster, like its neighbours, in imitation of stone. The Georgian sash windows would then have sat more comfortably in its neo-classic street frontage and only the peg-tiled roof would have betrayed its earlier origins.

Fig. 3.7. One of a series of wrought-iron L-ties in Oak Cottage, Great Yeldham, Essex. The front wall was removed when the jetty was under-built and the new one reinforced with iron. The line of the original bressummer is delineated by the white bleaching of the joists.

Fig 3.8. A nailed in tie rod in a cottage in Rattlesden, Suffolk. The original wattle and daub infill has been removed and replaced with brick nogging. The increased weight bulged out the wall which then had to be tied to the main spine beam. This is an early Victorian alteration and the tie rod is circular in section. The present owners have compounded the problem by removing the internal lath and plaster which was stabilising the frame.

Fig. 3.9. A plate from The Builder of 1848 p495 showing a composite beam in Middesex Hospital. The oak elements are stressed with wrought iron tie bars.

Fig 3.10. Phase plans of Hylands House prepared by Esmond Abraham. All the post 1797 work was achieved by tying the timber elements together with bespoke wrought-iron ties. In 1842 the house was remodelled using wrought-iron I-beams.

Fig. 3.11. A plate from J Newlands book The Carpenters Assistant of 1857-60 showing the comprehensive array of off-the-shelf ironmongery used in Victorian timber construction. Illustrated are bolts, stirrups, gibs and cotters, U-clamps and tie-rods.

Chapter 4 has no figures.

Chapter 5.

Fig. 5.1. A hooked tie removed from the Barley Barn during renovations in 1989. The section is constant and has been twisted through ninety degrees to facilitate the hook. Three large, rose-headed nails were used to fasten it and the areas around the punched holes have been upset locally. There are few hammer marks indicating the original strip was milled. Most likely 19th century.

Fig. 5.2. A hooked tie compared to a cramped L-tie. This tie has been worked hard under the hammer. The arm has been fullered and drawn down to a tapering section. The crook has been upset so the change of plane can be achieved without twisting and the tail also fullered and drawn down. The circular holes have been hot punched without local upsetting. The tip has been broken off and may have been originally cramped.

Fig. 5.3. A hooked tie with a cramped point in-situ in the Barley Barn, Cressing Temple. A pair for the hook-tie in Fig. 5.2. It is fastened with circular headed clout nails. The archaic features of this tie may indicate it has been re-used or refastened with 19th century fixings.

Fig. 5.4. A typical early L-tie securing the under-built front of Oak Cottage, Great Yeldham. The marks of the hammer are quite clear as is the upset crook. The arm is pierced to take nails and also nibbed for a square staple. The tail has also been pierced for a nail. The underbuilt jetty was recorded in an early 19th century painting and so indicates an 18th century date for the tie.

Fig.5.5. Often the only evidence for L-ties is the presence of the tail as the arm is buried in the building. This is one of a series used in a wholesale repairs of Oak Cottage, Great Yeldham.

Fig 5.6. These L-ties on 31 High Street, Lavenham have been spread and pierced for nail holes. This appears to be a local feature in Lavenham, Suffolk.

Fig. 5.7. An L-tie with a spread and nailed terminal on the Guildhall in Lavenham. Compare with Fig. 5.6.

Fig.5.8. A stapled L-tie on the façade of The Manor House, Lavenham. The terminal has been bifurcated in a decorative fashion. Lavenham was a failed wool town which resulted in the crystallisation of the buildings in the 17th century. There was an upsurge of traditional repairs in the 1950's and this mild steel tie was made then. (Owner, pers comm).

Fig 5.9. Orchard Cottage, Foxearth, Essex. A 'three-times-bent' serpentine L-tie with a stapled arm and a cramped tail. The square section nails also have square heads. This is identical to those described by Harrison in his report of the 18th century barn at Acol, Kent.

Fig. 5.10. A plate or strip binding across a simple scarf in The sole plate of Corwainers, Lavenham, Suffolk. Judging by the poor quality metal which has corroded badly and the simplicity of the scarf, the repair is likely to be 19th century or later.

Fig. 5.11. A strip binding the south-west corner of the Barley Barn at Cressing Temple, Essex. The strip has many redundant holes and is likely to be a piece of re-used scrap and so its emplacement is undatable.

Fig. 5.12. A strip repair to stabilise the corner post of Cordwainers, Lavenham, Suffolk. Re-used pieces like this are difficult to date. Photographic evidence or contemporary paintings may be of some use where the house is well-known.

Fig. 5.13. A flitchplate inserted into the failing boom support of the Harwich Crane. A repair effected in 1990 using stainless steel.

Fig 5.14. A fishplate bridging a butt joint in the top of Lode Mill, Cambridgeshire. Four square-headed bolts are used to locate it. Dated to the mid 1800's.

Fig 5.15. A strap cramped at either end. The cramp has been drawn down, presumably to increase its length and appears to be made of a reused cart tire. This would date it to the 18th century or earlier. The other fixings may provide a closer date.

Fig 5.16. A broken cramp that has been replaced with a stapled L-tie. The uniformity of its form and fixings indicates a 19th century date for the L-tie. The cramp must therefore be earlier.

Fig. 5.17. A 20th century mild steel strip bracket originally used to secure a failing door post. The machine drilled and countersunk holes as well as its milled uniform section make it simple to identify.

Fig 5.18. A U-strap on an arcade post of the Wheat Barn at Cressing Temple. Of uniform section with drilled and countersunk holes and nailed in with round clouts this repair must date to the end of the 19th century or later. It has been repositioned at least once.

Fig. 5.19. A nailed in internal bracket on a main tie beam in Lode Mill, Cambridgeshire. The large square headed nut ensures the bracket cannot be torn out. Dated to the mid 1800's.

Fig.5.20. A threaded draw-tie from the Stable at Cressing Temple. One of a series of four, the others are still in-situ. The arm is tapered and nibbed for a staple and the square punched holes are deliberately offset to prevent the nails splitting the grain of the timber. Early to mid 19th century.

Fig.5.21. Close up of the threaded end of a draw-tie. This is a typical profile and appears to be swaged rather that die-cut. Of good quality wrought iron, there is little corrosion.

Fig. 5.22. A stapled draw-tie with a forelock key. The inset shows the forelock key. This unusual tie, found in the Wheat Barn at Cressing Temple is most likely to date to the early 1500's when a great sequence of works was carried out on the barn.

Fig. 5.23. A forelock bolt on a wall post in the Barley Barn at Cressing Temple. The triangular forelock passes through a slot pierced in the tip of the shank. A thick metal washer is kept under tension with a hide washer.

Fig. 5.24. This large forelock bolt has a shank diameter of nearly an inch. The nailed on flange takes place of a washer and helps to spread the considerable load preventing the bolt from pulling through.

Fig. 5.25. The round, mushroom head of the forelock bolt pictured in Fig. 5.24. This round head always distinguishes forelocks from threaded bolts which require square heads so that they may be turned with a spanner.

Fig. 5.26. Oak Cottage, Great Yeldham. The mushroom heads of two forelocks bolt passing through a clamp on the back wall. In this case it was possible to see the actual forelock outside. Compare this with the T-pin used on the front wall pictured in Fig. 5.28.

Fig. 5.27. A forelock bolt in the jowl of a split wall post in the Barley Barn at Cressing Temple. The hide washers are clearly visible and most of the key has corroded away. The later addition of the L-tie above has relieved the stress and made the forelock redundant.

Fig. 5.28. The head of a T-pin securing a clamp on the front wall of Oak Cottage, Great Yeldham, Essex. Because the other end is not visible it is not possible to tell if this is the head or the terminal of the pin. In domestic buildings the bolts normally have their heads on the outside whereas in farm buildings the opposite is true.

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.

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. 5.30.

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).

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.

Fig. 5.38. Two bolts dated to 1714 by the accounts of Ashes Farm, Cressing, Essex. The heads are heavy and flat topped and the nut not far off being a cube of metal.

Fig. 5.39. A 19th century bolt head in the Horse Shelter at Cressing Temple. Built between 1842 and 1876 (from map evidence) all the hanging knees are bolted in place with these distinctively headed bolts.

Fig. 5.40. The other end of the bolt in Fig. 5.37 above. The nut is very much slimmer than those of a hundred years earlier and it sits on a machine made washer. The tip of the thread is blunt. Compare with Fig. 5.20.

Fig. 5.41. The Horse Shelter at Cressing Temple is a typical mid-Victorian farm building. All the hanging knees are secured with wrought iron square-headed bolts. Repairs to the 18th century Wagon Lodge, close by on the site, mimic this design exactly.

Fig. 5.42. A composite tie on the front of the Marlborough Head public house, Dedham, Suffolk. This resembles the pin tie found in the Wheat Barn at Cressing Temple (Fig. 5.27) but it has been passed through a face-plate to secure the joint.

Fig. 5.43. A pair of L-ties made from re-used cart tires from Ashes farm, Cressing, Essex. The components may be 17th or 18th century but the crudity of the work suggests the 19th century. Ties like these are difficult to date.

Fig. 5.44. A pair of plates made from re-used cart tires. One has broken and been superseded by a well-wrought L-tie and this would suggest that they are all pre-Victorian. It is necessary to carefully examine the features of each tie to determine a likely period.

Chapter 6.

Fig 6.1. A photomicrograph illustrating the fibrous nature of wrought iron. The iron and slag are intertwined in close physical association but do not constitute an alloy. (Aston & Story, 1936).

Fig. 6.2. A fractured wrought iron bar showing its fibrous structure making it ideal for working under the hammer. (Aston & Story, 1936).

Fig. 6.3. A cramped L-tie with an upset crook. The metal has been thickened locally to strengthen the curve.

Fig 6.4. A local upset to provide a shoulder for a staple and more metal for a punched hole. Upsetting achieves this without thinning the section.

Fig. 6.5. A side view of an upset cramped L-tie. The metal has been locally thickened and the plane of the tail changed without twisting. However, the holes have been punched without upsetting, causing a slight entasis around the holes and a ragged finish.

Fig. 6.6. A double-shouldered L- tie. The tie has been formed by hot-cutting the bar along its length, forming two upsets and then welding the halves back together in the fire. A complicated L-tie it has been used to reinforce a Victorian partition in the Granary at Cressing Temple. There is another in the Barley Barn. Both are likely to have been reused.

Fig 6.7. Stapled L-tie in the Barley Barn at Cressing Temple. The arm has been drawn down in both directions, probably to compensate for the upset crook of the L. This gives an elegant profile without loss of strength.

Fig 6.8. The terminal of this L-tie on the Guild Hall, Lavenham, Suffolk has been spread to accommodate a nail hole. It will also resist twisting to a greater degree.

Fig. 6.9. A fuller is used to extend the length of a bar by reducing its thickness without spreading. The ripples caused by hammering the metal over the blunt wedge are smoothed out with a plane hammer afterwards.

Fig. 6.10. The hardie resembles a fuller except that it has a definite cutting edge. The red hot work is struck on the hardie until it parts. Large bars are hit with sledge hammers by a second smith called a striker.

Fig. 6.11. A hot set resembles a hammer except that it has a chisel point. The smith holds the set while the striker hits it with a sledge.

Fig. 6.12. A typical anvil of the London pattern. The curved bick (beak) can be used to form soft curves while right angles can be formed across the table.

Fig. 6.13. A scroll wrench set in the hardie hole of the anvil. This allows the smith to easily manipulate the bar to the right curvature.

Fig. 6.14. A set for hot punching holes. This would be placed on the hot work over the hardie or pritchel hole and struck with a lump or sledge hammer.

Fig. 6.15. A die stock for cutting external threads. This example from 1900 illustrates the unchanged form that persists today.

Fig. 6.16. A hand driven bench thread cutter used for cutting British Standard Whitworth threads. A standard universally accepted by the 1860's. On the bench in front is a small die stock with two adjustable dies.

Fig 6.17. A collection of wrought-iron smith's tools. Their form, although refined by time, remained constant. (Seymour Lindsay J, 1964).

Chapter 7.

Figs 7.1 & 7.2. A hand-wrought iron nail showing its square, irregularly beaten shank and six-sided, rose head. This example is early 16th century taken from the roof of the Tudor aisle of St Mary's church, Bocking, Essex.

Figs 7.3 & 7.4. A hand-wrought nail from the 19th century with a four-sided head. The point has broken off from being clenched through a stable door.

Fig 7.5. An wedge sectioned hand-wrought nail from the bread oven at The Castle Inn, Earles Colne. The oven dates to c.1840.

Fig 7.6. Type A cut clasp nail. These were developed at the end of the 18th century. Cut in a water-powered guillotine both faces are burred. The head and point was hand forged. (IMACS User's Guide).

Fig 7.7. Type B cut clasp nail. The machinery for cutting this type of nail was introduced in 1810. It is identified by having two burred edges on the same face. (IMACS User's Guide).

Fig 7.8. A stamped cut clasp nail of the early 20th century.

Fig 7.9. Round section clout nails from the early 20th century still with their original box. These are used in late Victorian repairs onwards.

Fig 7.10. The stamped head of a modern clout nail.

Fig 7.11. A selection of clout nails from the early 20th century. These came from a Wheelwrights shop at Kedington, Suffolk. The first on the left has a heavy round machine-made section with a flattened tip and is the easiest to identify. The others all have irregular shanks and are much more difficult to date.

Fig 7.12. Two square-shouldered staples. The smaller is typical of those used to secure iron ties. The larger has been redeployed as a hinge.

Fig 7.13. The Craft Barn at Cressing Temple, Essex. A modern iron tie from the 1950's is fastened with a round sectioned staple. The tie itself is of poor quality wrought iron and has corroded considerably.

Fig 7.14. Domed screws were the earliest type and persisted until butt hinges increased the demand for countersunk heads. These are modern ones machined in brass and the pattern has barely changed since the 1840's.

Fig 7.15. The design drawing of a Robertson screw from 1907. These were never popular in the UK and it is unlikely that one would ever be found in an ironwork repair.

Fig. 7.16. A modern Phillips headed screw also known as a Pozidrive. This was developed in 1936 and so can only feature in modern repairs or replacements.

Fig.7.17. A bolt dated to 1714 compared with a 19th century bolts used by the Great Eastern Railway in the late 1800's.

Chapter 8 has no figures.

Chapter 9 has no figures.

 

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