Early Construction

It should be noted that the dates of developments vary depending on the locality. The Late Medieval period started in Britain about 1200 or later and ended about the early 16 th C with the Reformation. These dates are later than for mainland Europe because it took time for change to move north-west, although experts have differing views on dates. Similarly, within Britain, developments in house building started earlier in the more wealthy South-East of England and generally spread north-west to the English Midlands and the north over a period of a hundred years or more.earthfast Unless otherwise stated, dates in this site refer to the South-East.

Until about 1200 AD, in areas with supplies of wood, many dwellings were made of posts ("earth-fast posts") pushed into the ground to keep them upright. Other wooden members, also made from young trees and branches, were added to give rigidity, and a thatched roof was added.

The picture is an example of a reconstruction at the Avoncroft Museum.

However, the posts rotted where they contacted the ground and the dwelling usually lasted no more than a generation. At about this time came the First Technological Breakthrough: the use of a stone plinth and timber sill along with the use of strong timber joints. The stone plinth consisted of a line of stones, perhaps partly below ground as well as above, laid along the foot of walls. On this was placed a sturdy wooden sill (that is, a horizontal), usually of oak and shaped to a rectangular cross-section with a broad axe and then by an adze. Posts (that is uprights), also rectangular, were then inserted into the sill and secured by mortise and tenon joints held together by oak pegs. Iron was seldom used because it was precious and the acid in the oak could corrode it. This joint was also used to join the other frame members which were also rectangular.

The mortise and tenon joint is exceptionally strong and rigid. There are five main ways in which any structural member can fail: bending; compression; extension; torsion (that is, twisting); and shearing. Shearing occurs when there is an attempt to slide parts sideways, as when a pack of cards is spread out on a table by sweeping your hand over the pack from one side of the table to the other. If the pegs failed they would do so mainly in shear while resisting the pulling out of the tenon.Mortice & Tenon Animation Also, the shoulders of the tenon would strongly resist any attempt to alter the angle between the mortise and the tenon (although shrinkage of the oak opened gaps which reduced this effect). The plinth raised the wood above the main source of damp: the ground. No longer were structural members in direct contact with it. This extended the life of the building by a huge amount, so much so that it gave the house an indefinite life, given reasonable maintenance.

Indeed, the earliest timber-framed houses existing today are of this construction and are believed to have been built in the middle of the 13 C. They are at Boxted in Kent, and at Upton Magna just west of Shrewsbury recently dated to 1269 by using dendochronology, By the late 14 C peasant houses were being built which survive today. Many timber-framed houses also survive in France and Germany, and the construction was also used in Canada.The oak used for the frame was cut during the winter or spring and used immediately, partly because seasoned oak is very hard to work. This partly accounts for the interestingly distorted timbers in old houses.

These Late Medieval houses, occupied by merchants, yeomen, farmers, craftsmen and other prosperous people, were Open Hall Houses (a basic design that had been in use for centuries). Design details are at the end of the Picture Gallery along with information on use. The layout was very standard. The largest part was taken up by the Open Hall which was used by the master, his family and his servants and farm labourers as a dining and general living area. Indeed, it was the dominant room from the most wealthy downwards until the layout was modified or replaced during the Transitional Period which came at the end of the Late Medieval period. These changes eventually led to the modern designs of Georgian and modern times. There was little separation into social classes as far as the mechanics of living were concerned. The Hall was open to the thatched roof through which escaped the smoke from a fire placed in the centre in wealthier houses or at the side in poorer ones. There was no ceiling and no room above. The smoke-blackened roof timbers are often a clue today that a much-altered timber house was once an Open Hall House. There are many Hall Houses in Britain, especially in Kent. Many have been altered over the years.

By the end of the 14 C many substantial houses had been built in the South-East of England for peasants, and by the end of the 16 C humbler dwellings were seeing the benefit of this type of construction and layout.

The ground floor was made of beaten earth mixed with clay and often animal blood as a hardener, whilst in the South-East beaten chalk and soured milk was used. Contemporary descriptions and the views of modern archeologists vary on how sanitary these must have been!

Timber Framing

A timber-framed house is one whose substantial timbers are joined to form an open rigid frame which supports the roof. With box frame construction there are additional posts and rails that form the frame of the wall, the intervening spaces (infilling) being filled with (often light-weight) material to provide weather-proofing. With cruck construction there can similarly be additional posts and rails and infilling as for box frame construction. In another, quite different, method of building which does not use much timber,the wall may be of mass construction (that is, of stone or brick or even clay).

Cruck Construction

A cruck consists of a matched pair of curved timbers (blades) sometimes coming from two matching tree trunks. The advantage of a matching pair included the likelihood that they would distort in the same way. They were joined at the top, and with a tie-beam half-way up, to form an "A" shaped frame. A cruck house would have at least two of these frames to form the gable ends. They were commonly 16 feet (4.9 m) apart forming one bay. crucksAdditional cruck frames (without the tie-beam) could be provided in between as required for the length of the building. The width of the building (the span) could sometimes be very large especially in barns - Leigh Court Barn in Worcestershire spans over 30 feet (9 m). The walls were then erected and these could be of mass construction which would usually conceal the timber. The mass construction consisted of stone or clay, or sometimes brick which was often used a s a substitute for an earlier material. Alternatively, the walls could be of timber and consist of a sill and posts and rails and infill panels as for box-frame construction, thus usually revealing the timber. The sketch also shows two of the three purlins on the roof (one being on the ridge) and the two wallplates also running the length of the building attached to the ends of the tie beams. Not shown is the post attached to each cruck blade near the bottom and reaching to wallplate level to form a vertical member for the side walls, nor the padstones under the floor of each cruck blade or (in later constructions) the stone plinth, nor the timber sill running under all four walls. Cruck construction was common in Central and Northern England and in Wales but not in the South-east, and continued to be developed and used for new building into the 19 C. Over 2,000 cruck-framed buildings have been identified and still stand today, although it is often difficult to detect them as such from a cursory look, often because of alterations. The best place to see them is in the English Midlands, especially around Hereford.

Box Frame Construction

This method was more common and more widespread. Here, a rectangular frame of sill, posts and a wall plate was erected on a stone plinth and joined by mortise and tenon joints. One frame made each of the two side walls of a bay and one made each of the gable ends. As in the case of cruck construction, additional bays were added to give the required length of the building. boxframeStudding (vertical members) was installed between the posts. In the South-East the studding was relatively close together, so forming tall narrow openings. From South-central England (that is, from the Isle of Wight area) to the West Midlands and into central Wales the studding was more substantial and its spacing was greater and rails (horizontal members) were added, forming square openings so distinctive of those areas. The sketch (of a two-bay house) shows the latter, only partly complete and without the roof. The joints used were more complex than those involved in cruck construction.

Angle braces provided rigidity. A triangle is a very rigid structure because if forces succeed in distorting it, one or more members must buckle or break. A square or rectangle on the other hand can distort into a parallelogram without any of its members being affected. (This is why a man's bicicycle consists essentially of two triangles.) For aesthetic reasons, these Angle Braces were sometimes much more numerous than technically required, and highly decorated. The Feathers in Ludlow, and Little Moreton Hall in Cheshire (1559) with its "magpie style", are extreme examples.

The openings were filled by infill panels to make the structure weatherproof. These panels often consisted of wattle and daub. First, slightly oversize staves were inserted vertically about 5 to 6 inches (125 to 150 mm) apart into the rails by springing them into slots.wattle Then lengths of split oak or hazel or ash were woven horizontally in and out of the staves to form the wattle (see nearby picture which was taken in Germany.) Next, a suitable local wet clay with straw, cow hair or cow-dung, (the daub) was thrown against both sides of the wattle to form the desired thickness. (The Avoncroft Museum picture at the top of this page gives a glimpse of this.) It was important that the daube thrown on to one side met and edhered to the other. A thin coat of plaster was then applied and limewashed or washed with ochre. Finally, the panel was limewashed which was washed over the generally grey timbers. All of these materials were obtained locally, Medieval life being self-sufficient.The oak weathered naturally to a silvery grey and although the distinctive practice of painting them black existed at least as early as 1822 it was made almost universally fashionable in Victorian times. Therefore the relatively recent "magpie" look would have been almost unknown before then. The ease of breaking the panels led to the designation "breaking and entering" as a criminal offence, still in use today.

Alternatively, the panels could be made of brick, and although this was possibly used in original Medieval construction, it was more often used later, either as original construction or as a later replacement for wattle and daub. As the brick could take some of the load it was probably one of the the reasons why carpenters reduced the size of their timbers for new construction. However, the flexibility of wattle and daub allowed the frame to move with any subsidence (not uncommon given the rudimentary foundations) and thus re-distribute stresses and strains over a large part of the building. In Lincoln there is a spectacular example of this in operation. The rigidity of brick tended to localise and concentrate these forces, sometimes causing more localised but more serious damage that required repair. Box Frame construction continued until almost to the present day. Indeed, my cottage (see picture in the Introduction) was doubled in size in 1989 by Border Oak Ltd. using exactly the same construction described above (except that the infill panels have modern thermal insulation.)

These early houses are called Hall Houses or Open-Hall Houses because the main area (often consisting of two bays) was open to the roof through which the smoke from a central hearth escaped. Members of the household (servants and ordinary visitors) ate and slept here. Details are in the Picture Gallery (ground plan and section).

During the last few hundred years timber framing became unfashionable among aspiring people and both the interior and exterior were sometimes completely plastered to hide it. Sometimes old houses were plastered later in their lives while later houses were plastered when built. No. 1 Broad Street in Ludlow was plastered at one time. Slashes were hacked into the timbers to help the plaster to stick and can be seen today both inside and outside many timber-framed houses where the plaster has been removed to satisfy modern tastes.

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