Gauged Brickwork

Gerard Lynch

• Publisher: Routledge
• Year: 2018
• ISBN:
  9781317742609
• Edition: 2
• Topic: Architecture
• Subtopic: Historic Preservation in Architecture

Gauged brickwork is a term used to describe the superior finish required in the details of an important brickwork elevation, such as moulded reveals, arches, string courses and other forms of ornamentation. This is achieved through shaping the individual bricks to produce a high degree of regularity, accurate dimensions and extreme fineness in the joints. This practical handbook combines simple diagrams and photographs to describe each stage of the process, from rubbing, cutting and shaping the bricks to laying and carving them. It emphasizes the importance of this skill in repairing and repointing rubbed and gauged brickwork and the damage that can be done by those unskilled in the craft. The second edition of this standard reference work has been substantially updated with new material, including additional photographs and illustrations to explain the various procedures and applications. It also now offers a fascinating and detailed historical perspective on the development of this important craft. The insights gleaned from this revised edition will be extremely valuable to architects and builders involved in conserving and repairing gauged brickwork, and also to those who are required to commission new decorative work to a high standard.

Chapter One
Gauged Brickwork

Introduction

By definition, to gauge is to measure, set out and work exactly objects of standard size so as they conform to strictly defined limits. This term is eminently suitable for this class of brickwork. Gauged work is the name given to brickwork where the bricks are worked or gauged to a certain size or shape. Bricks used for this purpose are specially prepared and are known as rubbing bricks, ‘rubbers’, or ‘cutters’; the latter denoting a slightly harder type of brick for gauged work like the ‘Malm or Suffolk cutter’. They can be cut, filed or carved like cheese, yet their surfaces can become exceedingly hard with an internal mineralogical reaction, initiated during the laying phase after the bricks are dampened, leading to case-hardening. This, combined with their open-pored structures, enables them to withstand even the polluted atmospheres of big towns and cities.

There were many varieties of rubbers and cutters. Those most commonly used in the south of England, where gauged work was most employed, were Fareham Rubbers made by H. Johnson and Company of Fontley, Hampshire, whose bricks were a deep cherry red in colour. White Suffolk Cutters, or ‘Clippers’, which were handmade from finely ground clays and burnt in kilns, had a creamy white appearance but soon became dull in smoky town atmospheres. Malm Cutters were made from carefully washed brickearth and were the best of the London stock range of bricks; they were slightly underburnt and light yellow in colour. A rubber brick highly favoured in and around London and, until 1984 still seasonally produced, were those made by Thomas Lawrence of Bracknell. These bricks are more orange in colour and of a sandy, red clay, sieved to remove pebbles, hand-moulded, dried in unheated sheds and burnt in a coal-fired down-draught kiln, protected from the greatest heat by facing bricks. They are rather longer than ordinary bricks to allow for rubbing and cutting to shape, their general size being approximately 245 mm × 120 mm × 80 mm. They are often known as TLBs – these being the initials of the manufacturer stamped on the bed face of the brick.

Gauged brickwork is of a precise character and the sharp arrises must always be protected. Much care is needed in handling the prepared brick, especially once dampened in preparation for laying, when even the rub of a careless finger or the web of the hand between finger and thumb will round an arris.

Unfortunately, high production costs resulted in a major decline in demand for gauged brickwork during the past four or five decades. It is generally used nowadays only on old buildings that are being repaired, on new buildings where continuity is required with neighbouring buildings of gauged construction, or for a discerning client seeking high quality brickwork.

This decline has almost resulted in the exclusion of gauged work from apprentices’ craft training, with the reduction of the learning period from five years to three. Today, as the training emphasis has shifted to ‘fixing’ rather than ‘crafting’ skills, gauged work has only the briefest mention – and insufficient academic support – in the Level 3 syllabus of the National Vocational Qualification (NVQ) for bricklaying under ‘Complex Masonry Structures’, with unrealistic dimensional tolerances for such precise practical work. In response to this, National Occupational Standards for new Level 3 NVQs in heritage skills have been developed with the intention of creating career paths through advanced traditional craft skills to higher qualifications recognising this specialist niche in the sector. This will give a larger number of apprentices the opportunity to experience traditional craft skills; those being fortunate enough to have access to appropriate projects will hopefully be sufficiently inspired to achieve higher standards and qualifications. Certainly it is to be welcomed that the failure to cater for traditional craft skills is at long last being recognized. However not all colleges should, or could, offer these new Level 3 units, and so a large number of apprentices would miss this opportunity.

Most companies that come into contact with historic buildings need apprentices to be learning modern and traditional knowledge and skills in tandem from the outset, so that they are more capable of working on the various types of contracts they undertake as their apprenticeship progresses. One must teach apprentices the knowledge of both the traditional and modern aspects of their craft, its respective tools, materials and skills, right from the beginning of their apprenticeship, progressing and responding to their individual aptitude, skill level and maturity from basic to increasingly advanced levels.

In the case of gauged brickwork, the rigid modular structure of current craft training makes teaching this subject very difficult in terms of the amount of time allowed overall for training. Under the old City and Guilds system, gauged brickwork was not introduced until the second or third year, depending on the length of apprenticeship. Like then, it needs to primarily be aimed at those students who display the necessary interest and aptitude to succeed. Given the shorter time scale of NVQ training, this might have to commence at a basic introductory level at the end of their first year by initially defining gauged work and learning about rubbing bricks, the basic tools and the elementary skill of squaring a brick on the rubbing stone.

In the second year at a time appropriate within the curriculum and their respective skill development, these same students could be taught: how to set out and cut ashlared units and various simple mouldings; how to prepare a lime putty and silver sand mortar; to dip-lay and build a simple detail incorporating their ashlar and cut moulded bricks; and then, when dry, how to correctly finish the gauged work model by rubbing-up. The more advanced of these apprentices, who gain lots of bricklaying practice and experience within their particular on-site employment, could alternatively be tasked to set out, cut and build a simple, small-span semi-circular or segmental gauged arch.

As in other traditional areas of the craft, a holistic understanding and appreciation of what is necessary to undertake repair or restoration work on historic properties becomes with time an implicit part of one’s repository of knowledge and skills as a qualified craftsman. So it is with gauged brickwork when it is introduced and taught this way. After several years in the craft, it gradually becomes an increasingly easier skill to master, and the more complex enrichments one might eventually be asked to work on, less daunting.

Gauged work is of such a highly skilled nature that very few bricklayers are able to grasp all the necessary skills in a short time. Even in the past, the young apprentice called to the mysterious world of the rubbing and cutting shed was considered to have reached the peak of his craft. Yet it is a grave mistake to let this art die. It is increasingly argued by some that there is no need for bricklayers to learn how to do the setting-out, preparing and cutting, and rubbing in the cutting shed today as both the relevant brick companies with cutting facilities or cutting companies can supply this service. Though these services do exist, a bricklayer should still always be taught the traditional setting-out and a range of cutting and rubbing skills for several reasons:

• Bricklayers who know how to do this properly will always prepare the bricks with empathy for the next stage of their own or another bricklayer’s work (i.e. setting-out and building the prepared enrichment).
• It enables the development of the essential crafting skills necessary for quality bespoke repair and restorative works.
• The bricklayer taught how to set out and prepare gauged work in the traditional manner will always present a superior empathetic finish to any pre-cut work supplied by a brick or cutting company for on-site assembly than a bricklayer not tutored with those necessary skills and their underpinning knowledge.

As was always traditional practice, bricklayers tasked with gauged work should also be encouraged to become involved in the design stage of enrichments and their templets (traditional craft spelling for templates) for cutting and shaping the bricks. Failure to do this simply reinforces the movement away from ‘crafting’ to ‘fixing’ skills, impedes overall learning, and creates an unnecessary barrier for bricklayers in the complete production of a gauged work enrichment.

Anyone who has concern or responsibility for historic gauged brickwork should observe bricklayers asked to do this type of work who have never ever come across it before. Their attempts to do a fine job, valiant though they might be, expose their lack of knowledge and understanding of the fundamentals of the craft.

In the absence of gauged work within formal college training for apprentices and of mature, skilled and experienced bricklayers wishing to be introduced to the subject, specialist courses led by those with appropriate craft qualifications and experience in gauged work are needed to prevent the total decline of the art. As well as remedial work that needs to be executed with care and sympathy in the traditional ways, the revival of good quality brickwork in modem construction has prepared the way for new designs in gauged work. Bricklayers fully conversant with gauged work who are asked to execute their skills can not only command the top monetary rates commensurate with such craftsmanship, but will also be able to experience that excitement and satisfaction which only a true craftsman knows.

The Construction of Gauged Brickwork

Gauged brickwork is a highly sophisticated form of construction which, by its nature, makes certain demands upon the site organization of the job. These can be grouped under four main headings:

• Site accommodation – the cutting shed
• Initial preparation of the brick
• Cutting and reducing the brick
• Setting the work

Site accommodation – the cutting shed

When the bricks are first delivered to the job, they must be stored so that they remain perfectly dry. If they are damp, they will not work correctly during the process of rubbing and cutting.

To reduce the chance of damage during transit, the cutting shed should be sited so as to be as close as conveniently possible to the finished work. Where this is not possible or practical and it is found necessary to deliver the finished enrichments of gauged work for on-site setting, then all the prepared voussoirs, mouldings and ashlared units must be tightly contained within stout, high-sided, timber trays, protected from damage, and clearly labelled for identification.

The cutting bench should be arranged to allow for successful strutting of the bricks while they are being shaped and allowance must be made for ventilation. The shed must be kept clean and tidy, as a large amount of waste results from this type of work and rubbing produces considerable quantities of high silica content dust. Although some masterpieces of gauged work were undoubtedly turned out from very unhealthy sheds, dusty environments must be controlled today by the provision of adequate ventilation. The use of an industrial vacuum cleaner to remove all brick dust at each and every stage of the cutting and rubbing process, and the provision of a suitable facemask may also be deemed necessary.

Initial preparation of the brick

The objective of rubbing gauged work is to produce regularity, accurate dimensions and extreme fineness in the joints. The processes vary slightly with the particular work in hand, but four general operations include most of the work in general practice:

• ‘Squaring up’, as in ashlar work
• Straight moulded work
• Circular work, plain or moulded
• Double curvature work

‘Squaring up’ is the term used for the initial process of bringing each individual brick to a perfectly regular and geometrically true shape, with all faces square to each other.

For ‘squaring up’ to use for facework, one bed is brought to a true surface on a rubbing stone. A flat piece of York stone of about 370 mm to 450 mm square, or diameter if circular, by 50 mm to 70 mm thick is excellent for this purpose. One face is worked square with this bed.

The brick is then ready to be reduced to the exact length and depth required. For this purpose, a wooden box is constructed with a baseboard to which two sides, the exact length and depth of the reduced brick, are fixed perfectly square. The width of the box is usually made large enough to accommodate two bricks with enough room to insert wedging between to hold them tight during cutting. Into this box the prepared bricks are placed and wedged, with the rubbed bed resting on the baseboard and the surfaces of the squared faces against the opposing sides. A small batten called a bridge is rested centrally on top of the bricks to spread the pressure as the strut is positioned to hold the bricks and cutting box steady.

The bricks are then reduced to the desired size by sawing across the box with a wire bow-saw, keeping the wire tight against the edges. A common type of wire saw used for gauged work is created by twisting two lengths of 16–18 gauge iron wire together. This twisted wire must be as taut as possible when placed in the bow-saw frame. This is achieved using a hand drill and looping the other end of the wire around a bent nail or hook fixed to a post. The reason for using twisted wire instead of a toothed blade is that it keeps its direction better when cutting through the brick than a blade, w...