Encyclopaedia of English Medieval Carpentry M to R

The Encyclopaedia: M-R

n o p q r

Mancetter Manor:	Awaiting entry
Marton Church Cheshire:	Awaiting entry
Mason's Joint/Mitre:	Awaiting entry
Middle Littleton tithe barn:	Awaiting entry
Mortice:	Slot or recess cut into a timber to receive a tenon.
Mortice & Tenon Joint:	A joint fundamental to the carpentry of the Middle Ages, used to connect two timbers meeting perpendicularly or obliquely. The tenon is inserted into the mortice and then the joint is pegged. The joint works well in compression, but is poor in tension. Various types were developed; see below:

mortice and tenon joint — Mortice and tenon joint

Left: bare-faced tenon - the tenon piece only has one shoulder. This joint is often used for arched braces. Right: stub-tenon joint.

stub tenon — Left: bare-faced tenon - the tenon piece only has one shoulder. This joint is often used for arched braces. Right: stub-tenon joint.

housed mortice and tenon — Housed mortice and tenon joint.
This refinement is useful when the joint will be subject to high shearing forces, such as in a floor beam. See example below used in the tie beam to post framing at Needham Market Church.

	Literature: Brunskill (2007); Alcock et al (1996); Hewett (1997.)

Mullion:	Main vertical division of a window
Needham Market, St John the Baptist	‘The culminating achievement of the English carpenter’ H. Munro Cautley ‘The most remarkable church roof in England ... a truly astonishing achievement’ Herbert Cescinsky and Ernest Gribble. Before we begin to discuss this ‘astonishing’ late fifteenth-century roof, I should mention I have inexplicably lost my photos of it, but plenty are online, for example here. And below is a sectional drawing of the roof by Ernest Gribble:

	The carpenter at Needham built a hammer-beam roof of significant span, remarkable in itself, but then topped it off with a with a clerestory, creating a complex and exuberant work of art. Its structure is difficult to describe. Normal carpentry vocabulary is inadequate as the roof scrambles the boundaries of rigid roof-timber taxonomy. Nevertheless ... The hammer beams, from the ends of which the carpenter fixed pendant bosses, extend 6ft 6in (2m) into the church. Standing on the end of the hammer beams are the unusually long hammer posts, c.17ft (5.2m) long (Cautley, with some justification, called these ‘storey’ posts). The hammer posts extend to cambered tie beams framed just below the level of the clerestory. The tie beams are framed into the hammer posts rather than vice-versa and are arch-braced. The hammer posts then extend higher, creating the bay divisions of the clerestory, to support a heavily braced shallow-pitched roof. Unusually, about a third of the way up, the hammer posts are connected longitudinally (west to east) by - now then, what shall we call these timbers. The latest Pevsner volume opts for ‘tie beams’, although this seems unsatisfactory given their small section and their function (see photo below). But we are in uncharted taxonomical territory. Cautley suggested ‘strainers’, but how about simply ‘ties?’ Anyway, moulded, crenelated and shallow-arch-braced as they are, their function appears as much ornamental as structural. We are not done yet with hammer posts, however, for two hammer posts stand on each hammer beam (I am stretching the taxonomy here). The second, springing halfway along the beam near the hammer brace, rises like an ashlar piece to assist the lean-to roof. This lean-to roof shelters the ‘aisles’ of the structure and terminates at the base of the clerestory. A few details: The roof spans nearly 30ft (9m). At the junction of the hammer post and the tie beam the carpenter used a housed mortice and tenon. The tenon of the tie beam passes through the hammer post and into the principal rafter of the lean-to roof. Cautley thought this construction formed a truss which nullified any lateral thrust. But this has one rubbing one's chin and tutting in doubt. Surely the carpenter thought any forces generated by the heavily braced low-pitched roof were travelling vertically down the hammer posts, for the forces to be then carried diagonally to the masonry walls by the hammer-beam framing. The carpenter probably thought the principals propped the clerestory and secured the inner ends of the hammer beams, but any trussing action at tie-beam level would be limited by the pegs-in-tension framing. Anyway, a point for debate. The roof was repaired in 2018, so hopefully its structure was examined anew and fresh insights will be forthcoming. In an attempt to classify this remarkable roof, some have dubbed it a 'double hammer-beam roof' - which it most certainly isn't. Needham Market is a unique roof beyond classification. Perhaps Needham is an reopening of a structural cul-de-sac closed a century before: the aisle-derived hammer-beam roof. You notice I have not mentioned the ornamentation of this roof, the coving, the carved spandrels, the hammer-beam angels etc. - all by no means insignificant. For here, perhaps unusually in a Suffolk hammer-beam, it is the structural carpentry that astounds. Literature: Cescinsky and Gribble (1922); Cautley (1982); Beech (2015)

The carpenter at Needham built a hammer-beam roof of significant span, remarkable in itself, but then topped it off with a with a clerestory, creating a complex and exuberant work of art. Its structure is difficult to describe. Normal carpentry vocabulary is inadequate as the roof scrambles the boundaries of rigid roof-timber taxonomy. Nevertheless ...

The hammer beams, from the ends of which the carpenter fixed pendant bosses, extend 6ft 6in (2m) into the church. Standing on the end of the hammer beams are the unusually long hammer posts, c.17ft (5.2m) long (Cautley, with some justification, called these ‘storey’ posts). The hammer posts extend to cambered tie beams framed just below the level of the clerestory. The tie beams are framed into the hammer posts rather than vice-versa and are arch-braced.

The hammer posts then extend higher, creating the bay divisions of the clerestory, to support a heavily braced shallow-pitched roof. Unusually, about a third of the way up, the hammer posts are connected longitudinally (west to east) by - now then, what shall we call these timbers. The latest Pevsner volume opts for ‘tie beams’, although this seems unsatisfactory given their small section and their function (see photo below). But we are in uncharted taxonomical territory. Cautley suggested ‘strainers’, but how about simply ‘ties?’ Anyway, moulded, crenelated and shallow-arch-braced as they are, their function appears as much ornamental as structural.

We are not done yet with hammer posts, however, for two hammer posts stand on each hammer beam (I am stretching the taxonomy here). The second, springing halfway along the beam near the hammer brace, rises like an ashlar piece to assist the lean-to roof. This lean-to roof shelters the ‘aisles’ of the structure and terminates at the base of the clerestory.

A few details: The roof spans nearly 30ft (9m).
At the junction of the hammer post and the tie beam the carpenter used a housed mortice and tenon. The tenon of the tie beam passes through the hammer post and into the principal rafter of the lean-to roof. Cautley thought this construction formed a truss which nullified any lateral thrust. But this has one rubbing one's chin and tutting in doubt. Surely the carpenter thought any forces generated by the heavily braced low-pitched roof were travelling vertically down the hammer posts, for the forces to be then carried diagonally to the masonry walls by the hammer-beam framing. The carpenter probably thought the principals propped the clerestory and secured the inner ends of the hammer beams, but any trussing action at tie-beam level would be limited by the pegs-in-tension framing.
Anyway, a point for debate. The roof was repaired in 2018, so hopefully its structure was examined anew and fresh insights will be forthcoming.

In an attempt to classify this remarkable roof, some have dubbed it a 'double hammer-beam roof' - which it most certainly isn't. Needham Market is a unique roof beyond classification. Perhaps Needham is an reopening of a structural cul-de-sac closed a century before: the aisle-derived hammer-beam roof.

You notice I have not mentioned the ornamentation of this roof, the coving, the carved spandrels, the hammer-beam angels etc. - all by no means insignificant. For here, perhaps unusually in a Suffolk hammer-beam, it is the structural carpentry that astounds.

Literature: Cescinsky and Gribble (1922); Cautley (1982); Beech (2015)


Noggings:	Short lengths of timber inserted between studs, rafters etc., to provide stiffening.
Passing Brace:	Lightweight timber running diagonally across main vertical and horizontal timbers, typically from a post to a rafter and crossing a tie beam. Helps to stiffen a frame.

Passing braces — Generic aisled frame with passing braces.

Principal Frame:	Transverse wooden framework of major structural, and often ornamental, importance, consisting of principal rafters (see below) and other major timbers; often corresponds with masonry bay divisions (see below and Fig. b, and King-post Truss).

Tie-Beam Roof generic — Generic 'double-framed' roof, some timbers omitted for clarity.

Principal rafter:	Often called simply a 'principal', inclined timber of heavier scantling than common rafters; supports purlin(s) which in turn support common rafters; often corresponds with the bay divisions of a building (see above and Fig. b).
Purlin:	Longitudinal roof timber supporting common rafters, usually set in the plane of the roof; framed into the principal rafters, and/or set into a masonry gable (see above and Fig. b). Butt Purlin: Method of framing purlin to the principal rafter; see below.

Butt Purlins, Example at top is 'staggered'.

Purlin, Clasped:	Awaiting entry; awaiting illustration
Queen Post:	Strictly, a timber rising vertically from a tie beam to support a purlin or plate; set in pairs. Awaiting illustration
Queen Strut:	Vertical timber rising from a tie beam to support a rafter or a collar; set in pairs.

queen-strut Truss — Two examples of queen-strut trusses.

queen-strut Truss 2 — Two examples of queen-strut trusses.

Rafter, Principal:	See Principal Rafter above
Rafter, Common:	See Common rafter.
Reversed Assembly:	Similar to the English Tying Joint, but the wall plate is placed on top of the tie beam rather than vice-versa. See below:

Ridge:	Longitudinal timber framed at the apex of a roof, often called a ridge piece. In 1439 at St John’s Church, Bury St Edmunds, the ridge piece is called a ‘rof tre’. More generally, the line where the inclined planes of a roof meet. See illustration. Literature: Salzman (1952)

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