Javascript Menu by Archive 09 June 2005 - Tree Ring Analysis & Historic Thatch
Church House, South Tawton, Devon, UK





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Archive 9

WEB SITE NEWS  Cynthia Gaskell Brown 1st June 2005
Technical reports on the Tree Ring Dating analysis and the Historic Thatch came in during April and May. Stripping out of the building has progressed very quickly with plaster and pointing coming off many walls and floorboards lifted. A great deal of new interesting, sometimes surprising, information has emerged. It looks very much as if we are going to have to re-think the early history of the building.

Tree Ring Analysis
Ian Tyers made a second visit to Church House in April having found the samples taken in December were ambiguous. This time to our delight he has been able to match most of the samples - rather like you do with a bar code - to dateable examples from elsewhere in England and after doing statistical and other technical adjustments came out with dating for the three oak roof trusses (the western truss is elm and not dateable); for the two eastern floor beams and most precisely the lintels (bressumers) over the two ground floor fireplaces in the central chimney stack.

Its important to remember that the dates are when the tree was felled and not necessarily when it was used; the timbers may have been stored or even re-cycled from other buildings. However Ian notes that the oak was used "green" and as it happens the dates correspond quite well with the architectural and stratigraphic evidence.

Felling Date of Roof Trusses T2 - T4 = 1480 - 1490

Felling Date of Floor Beams E and F = 1468 - 1502

Felling Date of Fireplace Lintels G and H = Winter1699

 Trusses are numbered 1 to 4 from the west end; Floor Beams including the hearth lintels are lettered A to F from the west end

Ian also noted many details about how the timbers were worked by the medieval carpenters. Evidence for the use of broad axes for splitting and marking out the timber still survives. There are adze marks visible on the great beam above the western hearth; saw marks on the rafters and purlins change direction - evidence that show how a trestle was used, not pit sawing which came to be used in late medieval times; and carpenters numbers made by chisels to help match up joints on the roof trusses and on floor beams for partitions.

Drawing of Sections of Church HouseSections of the Church House, South Tawton, Devon based
on a figure from Keystone (Thorp et al 2003). The section
shows the location of the sampled timbers. From the roof
the timbers sampled from the southern equivalent are
labelled in grey boxes, those from the illustrated northern
timbers are labelled with clear boxes. The truss numbering
sequence (T1 - T4) follows that from the Keystone report.
The labelling sequence adopted for the floor beams (A-F) and
bressumers (G,H) in this report is also shown.
Bar Diagram of Dated Samples
Bar Diagram showing the relative and absolute positions of the
dated samples from the Church House, South Tawton. White
bars represent heartwood, hatched bars represent sapwood,
the narrow hatched bar represents the minimum number of
sapwood rings on sample. The interpreted felling date or
felling date range is also shown for each sample.

Historic Thatch

 John Letts sampled thatch on the inside of the roof last December and returned in February to excavate a small trench on the outside in February. The sample that he got from the fleeking layer (the layer that you can see when you look up into the roof) proved to be well-combed winter grown rye. This came from a crop that would have stood about 150cm (4ft 9 in) high in the field. It was harvested with a sickle at knee height (just below the third internode). Most of the ears of corn were still intact. The samples from Bay 1 near the west wall were very sooty; while samples from Bay 3 were not so blackened.

On top of the fleeking layer the base coat is also of rye but c.10cm shorter, much leafier and with only about half the ears surviving, the result of having been flailed or perhaps "lashed" vigorously against a solid object to remove the grain. The fleeking layer and base coat are largely intact and have almost certainly has been in place since the roof trusses were first covered (perhaps soon after 1490). The seven identifiable thatching layers above this are of wheat straw and the roof seems to have been repaired and patched little and often in the 16th century; the earliest surviving documentary reference to thatch repairs dates from 1569. John's report contains details about how the thatch was fixed at various periods, how much of the roof would have been covered by the quantities of straw recorded as being bought for Church House in the Churchwardens' accounts and comments on local traditional and modern thatching practices and on varieties of crop used. John includes notes of his conversation with Mr Wilf Butt of South Zeal who rethatched Church House in 1964 and 1986 using traditional methods and materials identical to those used by his great grandfather on local buildings.

The full reports on Tree Ring Dating and Historic Thatch are held by the Church House Management Committee and the results will be presented in greater detail in the interpretation material which will be available in the autumn.


View of Stripped WallGround Floor and builder's equipment

Restoration Work: Stripping Out the Church House

 Substantial parts of the walls of the Church House are now clear of plaster and pointing. A lot more information about the structure is now available.

The changes made when the building was converted to use as for Poor House in the 19th century are very clear. At the west end the blocking up of the ancient full width hearth in the 19th century can be clearly seen. It is quite rough upstairs though more substantial down below.

This must be the result of the work noted in the Church Wardens' Accounts in 1819: -

"To William Bevens, mason, for contracting Church House chimney, repairing west wall

ditto and including 13s 9d for Lime as per bill £2. 9. 9d"

The Oven that is now visible was clearly altered quite crudely at the same time and is a miserable rebuild of the 16th century oven which is recorded in 1575 as being thatched for by Botffilde for 4 pence.

But the most significant revelation is in the north wall (opposite the doors). It is now clear that along the north wall the Floor beams are set in a course of carefully squared stones running from east to west until broken by the first alteration to the west wall which probably happened in the 1570's. A layer of mortar or cob lies level with the top of the beams and then the upper part of the stone wall is set on this layer. This is very strong evidence that Church House was designed and built as a two storey building; and that the theory about two earlier phases as an Open Hall structure may well need to be abandoned. Of course this throws up the question of how the thatch became smoke blackened!

Both Ian Tyers and John Letts expressed reservations about the smoke blackening:-

John Letts writes " Although all of the smoke blackened thatch within this roof probably dates from a single phase of works different parts of the roof may well have been exposed to more or less blackening for a variety of reasons; e.g. partitions, location of smoke vents, leaky fireplaces... (p5)

Ian Tyers writes, when discussing the mixed numbering of the carpentry marks on the roof trusses." This leads to a series of interpretative issues with the thatch, the smoke blackening of both it and the timbers, the dating of the thatch and even the source of the smoke blackening since this is not of the thickly crystalline nature of much of the smoke blackening seen elsewhere. . . (p7)

Clearly there is lots of debate ahead.

Cynthia Gaskell Brown, Heritage Consultant. 31 May 2005



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