Agriculture Reference
In-Depth Information
density. Generally speaking mature non-hydraulic lime putty will weigh approxi-
mately 1.45 kg/litre, and will contain 640-650 g (equivalent dry weight) of lime
per litre, or 470-480 g/kg. Some of the less dense fresh putties (e.g. 1.35 kg/litre)
available may contain only 510-520 g per litre, or 370-380 g/kg. It is possible
to buy traditionally ready-slaked lime putty from specialist suppliers, delivered
either in plastic tubs or plastic sacks. Unless it is purchased as a super-fine putty,
due to the thin joints used in gauged work it will need to be passed through a
fine-meshed screen of 1 mm or less, to sieve out grit or core that would interfere
with the bedding and jointing of rubbers. Once a lime putty has been placed
into the dampened dipping box the desired amount of kiln-dried silver sand is
added and whisked fully into it until it is the consistency of whipped cream. The
only other additive that is sometimes added to the prepared mortar within the
dipping box, is a tiny thimble full of boiled linseed oil; an established traditional
practice, which helps to make the mortar more cohesive, work cleanly and pro-
vide a small degree of waterproofing. Boiled linseed oil, however, is a drier and
thus caution must be exercised with its use, so that only this small amount added
otherwise hairline cracks to occur in the joints.
Modern Use of Gauged Work
Today, due to the lack of craft knowledge and skill of gauged work amongst
bricklayers and the demand for speed on projects, most rubbing bricks are deliv-
ered to site ready-cut to size and shape for the architectural enrichment from the
brickmakers or cutting companies. Despite this, profiles still need to be erected
and the gauged work dry-bonded so that all lines can be established and trans-
ferred to them to guide work to level, plumb, gauge, and where necessary, to
correct radial alignment. Experience has shown that certain propri-etary damp-
proof courses are suited to some joint sizes and can be used with great success
for dry-bonding. If a problem is encountered with accuracy of fit and bonding of
machine-cut gauged work, then one must not adjust or interfere with the bricks,
first recourse must be to that company, for their assessment and advice.
Despite the modern movement towards machine-cut rubbers for on-site
fixing there is still sometimes a need to produce gauged work by using time-
honoured traditional methods; particularly when undertaking bespoke reme-
dial work on historical buildings. This involves having such equipment as the
large rubbing stone, cutting bench as well as the traditional tools and equip-
ment, such as the try-square, sliding bevel, cutting boxes, 'grub saw', twisted
wire-bladed bow saw, files and rasps etc. These and the established techniques
of their use have been described earlier, and are summarised as follows:
●
Squaring a Rubber
●
Scribing to a templet
