Construction of the barn

Frame

The main material used in the construction of the box-frame which forms the main body of the barn in English Oak. Groundcills and post plates were laid first and the posts were fitted by stub tenons into mortices cut into these base plates. The groundcill and post plates may have originally been laid directly on the ground… as the groundcills and post plates rotted some of them were re-laid on a low brick foundation or wall in early repairs.

Huge oak trees were selected for the 20 main aisle or arcade posts and the 20 wall posts and the 6 end-frame posts. These posts would have been shaped with a side axe and an “ankle-biter” or adze, and the aisle and wall posts placed upside down so that the bole or wider part of the lower trunk could be used to make a jowl at the top of the post to accommodate a three-way joint with the longitudinal arcade nad wall plates and the cross tie beams. The main posts were steadied by shores or bracing beams stretching diagonally across the aisle, and longitudinal and cross wind braces from the arcade post to the arcade plate and tie beam.

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Note that the assembly of these three-way joints is ‘normal’ on the main or arcade posts, but ‘reversed’ on the wall posts, ie: the tie beam is on top of the arcade plate in normal assembly on the main posts but the aisle tie beam is below the wall plate on the wall post. The jowls on the wall posts has been rotated through 90 degrees to accommodate this reversed assembly.

The wall plates, arcade plates and tie beams are also quite large and would have been similarly shaped from oak baulks.

The ten 20-feet tie beams span the width of the central longitudinal nave, and the twenty 10-foot aisle tie beams form the width of the two aisles. The longitudinal wall plates and arcade plates are naturally extended by a series of scarfing joints, and the length of these joints at Upminster barn shows either no shortage of timber in Essex in the 15C or an early date of construction.

Joints

Note that all joints are formed by shaping the components and held by tenons and round wooden tunnels or trenails. Two main joints have been used throughout the barn… the three-way post-head and tie-beam lap joint described above, which was in use from the 12 – 17C; and the edge halved scarf joint for the lengthening the longitudinal timbers end to end, in use from 1375-1650. The remainder are simple mortice and tenon joints and various lap joints, usually pegged. Some of the joints have been repaired over the centuries and iron straps and bolts have been introduced for extra support.

Cladding

Judging by the evidence of surviving mortices in the wall posts and end posts which are for horizontal rails the cladding was originally all of the same vertical boarding type of wide elm boards butted together. The later replacement repairs were in part horizontal lapped split oak weatherboarding now replaced by modern thin sawn deal weatherboarding. The weatherboarding is feather-edged for overlapping and also involved the insertion of extra posts and irregular supports in place of the horizontal rails. The cleft oak was probably left bare, but the deal would have been tarred originally but is now treated with creosote or other modern preservatives. The modern replacement vertical boarding has been robated, rather than butted to make it more weatherproof, but a section of the original boarding has been left in the midstrey on the north side.

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Thatch

The thatch may have originally been natural reeds culled from local beds at Bulphan or at the managed reed beds once present on the marginal marshes of the lower reaches of the Thames. Regular cutting of managed reed beds improves the quality of the reed.

Natural reed (Phragmites communis) was used to re-thatch the barn in 1965, but the central part of the roof was burnt by fire in 1973 and repaired again in 1975.

The natural reed is cut on the managed Norfolk Broads in winter, just before the new growth occurs in February. It is stacked for a while and then wetted for use, before being laid. The cutters wore protective clothing and waders and cut the reed with a scythe or a sickle. Gathering it under his arm a bow-shaped rake was used to comb out the rubbish and short reed at the lower end. The rolled bundle is then tied and bumped on a spot-board to even u[ the butt end. Each bundle is generally about 12 inches diameter. It is stacked in a flat-bottomed punt for removal to the bank or cutter’s yard.

In the old days the black-sailed wherry was used to transport large quantities as a deck cargo. The reed is measured by the fathom… the circumference of the butt… 6 feet. Orders are usually given as ‘per hundred fathoms’. Reed thatch will last about 50-60 years if well laid and recapped once or twice in its life.

The ridge of the thatch is formed by butting up the reed bundles on both sides and cutting off level, with a reed rope roll along the ridge to give it some body. Reed cannot be bent over the ridge so a more pliable material, sedge (Cladium mariscus) is used. This is usually in its green state and formed into a neat thick cap and held by a pattern of hazel rods and twisted spars. The lower edges are usually scalloped or cut into patterns. When harvested the sheaf is usually bonded with a band of sedge around its girth. The sheaves are supplied to the thatcher by the score (20). The sedge lasts about 20 – 25 years before it needs renewing.

The spars are derived from coppicing of hazel, or sometimes willow, every 10 years. The rods are cut into 4 to 5-foot lengths for sways and liggers or 30-inch lengths for pegs or broaches, split into halves and again into 6 triangular spars. The spars are provided as long ‘sways’ or rods to hold the thatch to the rafters; ‘liggers’ to fix the exterior of the thatch and ‘broaches’ which are twisted spars like hairpins with sharpened ends to hold the lengths in place. The spars are delivered in bundles of eight score… the thatcher usually twists his own pegs or staples as he needs them.

The thatcher calculates how much material is needed for the roof and stores it at the site. His tools for reed thatching are a reed-holder (with a bow and hook); iron thatching hooks (to hold the courses of reed to the battens); a claw hammer and a mallet; stitching and reeding needles; tarred cord; shearing hook, shears; spar hook, sharpening stones; a wooden Leggett (for dressing reed into position); and a pair of leather knee-pads (often improvised from old car tyres) and of course ladders; scaffold cord; bucket; spot board c30-inches diameter (to bump the butt ends of the reed bundles or shape them for the eaves).

The skill of the thatcher is difficult to describe, as he makes it seem so easy … he gauges the layers of courses, dresses the thickness into shape, trims the ridge, verge and eaves and gradually a neat roof emerges that will weather many a storm for some 50 -60 years.crown post in the centre of each of the principal tie beams, supporting a longitudinal collar purlin and cross or collar ties to the rafters. The common rafter pairs are halved at the ridge. There are no principal rafters and no ridge pole. Racking is prevented by the collar purlin. The rafters of the aisles are single rafters from the wall plate to the arcade plate, many have been reversed end to end in later repairs. The roof is steeply pitched for thatch and both gable ends are half-hipped.