Agriculture Reference
In-Depth Information
site. The general TLB is very similar in appearance to the specially formulated
TLB HCP bricks in current use at the Palace for chimney repairs, except that the
ratio of washed clay to sand is reversed from the proportion 25% clay/75% sand
(TLB HCP) to 75% clay/25% sand (TLB). This reversal of the ratio of the con-
stituent materials gives a stronger brick, more resistant to attack by wind and frost
and to arris damage. Whilst not so easy to hand-cut using a bow-saw, the stronger
bricks could be squared in the dry state using diamond tipped saws, roughly
shaped by grinding, reduced to template by hand-finishing and hand-rubbed/
stoned after construction….
Writing in
Renovation
of June 1988, the architectural historian Dan Cruickshank
describes how Lamb and Sons had developed their services for the client, spe-
cialising in supplying bricks for gauged work (Cruickshank, 1998, 1-5):
Lamb's bricks and arches division undertakes to produce full-size working draw-
ings, based on the architect's specification and requirements…. This service is
especially valuable if the arch or detail is a repair for an historic building, for
many mistakes in specification can be made by architects untrained in the trad-
itions of rubbed and gauged brick construction.
The bricks to form arches, when the geometry has been agreed, are cut by
machine saw with each brick being dimensioned according to a template derived
from the full size working drawing….
However, moulded bricks - ovolo or scotia for entablatures or stringcourses - are
still ground and rubbed, though the process is also now mechanised. But where
tradition remains firmly unaltered is in the size and quality of the bricks used for
cutting and rubbing….
The precision of the cutting allows for very fine joints in the manner of eight-
eenth century brickwork although Lamb's recommends 5 mm or 3 mm joints.
The latter remark regarding joint size is revealing. The lack of 'squaring' across
the rubbers, to ensure surfaces exactly at 90º to each other before cutting, and
the inability of machines to cut to precise tolerances with mechanised blade
oscillation, makes close jointing virtually impossible. It further recognises that
most site craftsmen were insufficiently skilled to set-out and work to former
tighter tolerances.
From 1987, the author, as Head of Trowel Trades at Bedford College of Higher
Education (BCHE), established contact with Robert Lamb, the owner of W.T.
Lamb and Sons. Over-sized rubbing bricks and pre-cut arch 'sets' were gen-
erously provided to support the author's efforts to re-introduce gauged work
back into the curriculum. Mr Lamb expressed deep concern over the dearth
of skilled bricklayers to do justice to his company's products and very much
welcomed the initiative.
