The Penn tilers of the 14^th century were remarkable specialists, particularly those who made the decorated floor tiles.  They possessed an extraordinary store of knowledge and skills about the selection of clays, the techniques of decoration, the making of glazes and the construction and control of kilns to reach a particular temperature.  No one in recent years has been successful in making even half-way acceptable tiles using the methods and techniques available to them at the time.

The shape and size of a kiln were decided by the shape and type of its wares.  A typical medieval floor tile kiln probably consisted of a rectangular or roughly square oven above a furnace area, about 6ft (1.83m) square internally, heated by two parallel flues or fire boxes which were arched tunnels up to 2 ft (0.6m) wide and 3 ft (0.9m) long, sloping gently down from the furnace.  The furnace would normally be below ground level to provide insulation and support and was fuelled by wood, typically oak and hornbeam, fed from the stokehole outside the end of the fireboxes.  A typical roof tile kiln would have exactly the same arrangements but with a rather longer rectangular furnace and oven, say 7ft 6 ins x 6ft (2.28m x 1.83m).

The furnace was spanned with a series of arches five or six inches apart springing from each side wall to a low central wall.  The gaps between the arches allowed the heat to rise up through the oven above, and were bridged with roof tiles to form a level floor on which the tiles for firing were stacked on edge, one on top of the other in an ingenious succession of tiers at an oblique angle to the one above and below.  This arrangement led the fire upward through ever diminishing apertures and distributed the heat as equally as possible from bottom to top.  It was the way in which the tiles themselves were stacked that created the flues that drew the fire through the kiln, and so a kiln could not be fired until it was full.

The different parts of the kiln were built of roof tiles stuck together with clay and the oven walls could be up to 4 ft or even  6 ft above ground level to make room for more tiers in the oven.  There was no side entrance to the kiln and so loading and unloading were carried out by climbing over the top of the wall.  The top of the oven was temporary and constructed for each firing.  It was made of three or more layers of old tiles stuck together with clay, with gaps to allow the heat to rise through the oven.  By placing other tiles over these gaps the draught through the furnace and oven, and hence the temperature, could be controlled.

Control of the temperature was vital.  If it was too low, the tile was under-fired with a soft friable fabric.  Over 1,000°C was needed to flux the glaze so that it melted and combined with the clay body, but at 1,100°C the tile bodies themselves would begin to melt if the clay was not carefully chosen, vitrifying and turning purple, hard, brittle and often warped.  Even with skilled management there was an unavoidable difference of 200° C between the hottest, bottom front and the coolest, top back of the oven and hence there were always some over-fired and some under-fired waste products to discard after each firing.  Without any thermometers, the tilers had to use their experience to judge the temperature by the colour of the tiles at the top of the oven and in the temporary roof.  The smaller the oven, the more control the tilers had over the temperatures throughout it.  Glazed roof tiles needed the same high temperatures but plain roof tiles needed less heat and so could be made in a larger kiln.

When it was raining hard, the kilns could not be used and they were generally only fired in June, July and August.  A typical firing took a week.  On Monday, the tiles were stacked in the oven, on edge and in tiers, and a temporary roof was constructed.  On Tuesday and Wednesday, a slow-drying fire was lit, with an oven temperature of less than 200° C, in order to drive out any moisture in the clay tiles that might otherwise expand and burst.  On Thursday, the temperature was raised to between 1,000 and 1,100° C with a final firing with brushwood faggots to send flames shooting right through the oven to clean the tiles by burning up any bits of ash or dirt on them.  The mouths of the fire boxes and apertures in the roof were then closed to prevent an influx of cold air cracking or breaking the tiles whilst they were still too hot. On Friday and Saturday, when the kiln had cooled down enough, the roof was dismantled and the oven unloaded.  Spoilt tiles that could not be used as kiln furniture were carted away and dumped in disused pits or on fields where we find them today.

Miles Green, Village Voice 2025.

ALTERATIONS AND ADDITIONS IN THE PARISH CHURCH – BFP 13/10/16 (p.7)

In order to meet the need of further seating accommodation, and to comply with the wishes of the Lay Rector (the Rt. Hon the Earl Howe), several alterations and additions have been made in the Parish Church during the last month. The Choir, which for 35 years has been seated in the Chancel, has now been placed at the top of the Nave, in front of the pulpit and clergy stall, in new seats given by Lord Howe, giving accommodation for 18 boys and 9 men. Forty new seats have been added at the west end of the church in the space formerly occupied by the gallery, the appearance of the building being thereby greatly improved. The clergy stall has been moved just outside the chancel and lowered by about a foot, and the old lectern removed and replaced by a beautifully-carved eagle lectern of oak, the gift of A.H. Birch-Reynardson Esq., of Stampwell, Vicar’s Warden, and which has been much admired.

A new choir vestry has been made in the south aisle, greatly to the satisfaction and comfort of the Choir, which renders such valuable help to the services of the Church. The family seats of Earl Howe in the chancel have been restored, the Lay Rector having expressed the intention of attending the services in Penn Church. The chancel steps, which had been mutilated and cut away by a former Vicar, have been made good; the floor is to be tiled in grey and white, and a new oak seat with doors at either end has been ordered by Lord Howe, and will prove a notable addition and improvement to the chancel. After being closed for three weeks, the Church was re-opened for service on Sunday, 1^st October, which happened to be the 18^th anniversary of the induction by the late Ven. Archdeacon Bourke of the present Vicar (the Rev. B.G.S. Kerby), formerly for six years Curate of Beaconsfield. The congregation entirely filled the Church, and in the course of his remarks the Vicar gave the following interesting figures: – During the 18 years that had passed since his induction, there had been 41 marriages, 116 baptisms, and 109 burials, the Churchyard having been enlarged for the first time in 700 years by a gift of ground by a parishioner, W.M. Grove, Esq., of Watercroft. The number of communicants had been 8,374 and the offertory had amounted to £1,365, while gifts and donations had been made to the value of £674. The offertory during the first three years amounted to £119, and in the last three years to £395. In addition, the Tower had been restored at a cost of £130, a lych gate erected at the north entrance of the Churchyard, the design of the Vicar, to commemorate the 700^th year of the Church (which was built in 1213), at a cost of a little over £100, and the Schools re-built and enlarged at a cost of £1,350 – on the whole a notable record, and one of which the parishoners may well be proud. The Vicar has preached 1,671 sermons, and hopes to add considerably to the number before he is called upon to give an account of his stewardship. The offertory during the day amounted to £3 7s. 10d., and was in aid of the Sick and Poor Fund. It is pleasing to record that universal satisfaction has been expressed by the people of Penn with the alterations and additions to their beautiful Parish Church.

HARVEST FESTIVAL.

Services of thanksgiving for the harvest were held on Sunday last, when the Church was packed with large congregations. The decorations were of the loveliest character, and were the work of the ladies of the parish and Mr Whapshott (head gardener to Dr Parshall, of Penbury Grove). The music was splendidly rendered by the Choir, (consisting of 15 boys and 6 men), and the Organist, Mr W. Crispin Winter, was at his best. The special preacher in the morning was the Rev. W.B. Trevelyan, of Beaconsfield, who greatly impressed his many hearers with a most eloquent sermon on ‘The Fruitfulness of Death’ from the words: “Except a corn of wheat fall to the ground and die, it abideth alone; but if it die it bringeth forth much fruit” (St. John xii, 24). The Vicar occupied the pulpit at the evening service, now said at 3.30 owing to the difficulty of darkening the windows. Special psalms were sung, while the lessons were read by Mr Birch-Reynardson and Mr H. Canvin. The offertory on these occasions has always been given to some outside object, such as hospitals, orphanages, or other benevolent institutions, and during the past 18 years the sum thus sent away has amounted to £105. This year, as the Church has been closed for two Sundays, the Vicar donated the thank-offering to the Wardens’ Fund for Church Expenses and it amounted to £8 10s. (? partially legible). The Rt. Hon. the Earl Howe and his brother-in-law, Mr John Eyre, occupied the Rectorial pew, and after the service Earl Howe expressed to the Vicar the great pleasure the beautiful service had given him, and warmly congratulated the Choir on their excellent rendering of the festival music. The population of the parish is now 633 (? first digit partly legible).

Originally published in the Bucks Free Press 13/10/1916