Experts from the Kent Archaeological Society have been clambering around inside a former chemist shop in Maidstone to try to solve an old puzzle. Exactly how old is the key question.

A London-based entrepreneur bought the vacant Central Pharmacy at 98 High Street earlier this year with the hope of turning it into a Thai restaurant, but when Dolmen Conservation, the firm tasked with the internal renovations began to strip out the wall linings they soon discovered there was more to the building than meets the eye - with windows apparently on the inside of the building, hidden doors, and timber beams that seemed to go nowhere and for no good purpose.

On Friday, Debbie Goacher, chairwoman of the Kent Archaeological Society's historic buildings committee, along with fellow committee member David Brooks, made a visit to try to make sense of it all.

Mr Brooks had visited before without reaching any firm conclusions, but Dolmen has now lifted the roof tiles off the building and exposed all the rafters, making it far easier to visualise the layout of the building.

From the vantage of the attic space, the KAS experts found a number of clues.

Mr Brooks said: "In the central part of the building there is soot accumulated on the walls right up to the rafters and on the underside of the beams, that indicates the space below once once a large open hall with an open fire like a medieval hall house."

Mrs Goacher pointed to the lack of a ridge tree connecting the rafters at the top of the triangles. Instead, to stop the rafters "racking" or tipping over to one side, they were held rigid by a collar purlin half-way up their height and braced with cross beams.

She said: "This type of construction was typically used in the 14th century."

The discovery of a crown post also indicated a very early construction.

Meanwhile both were delighted to find several carpenters' marks slashed into the roof rafters in Roman numerals giving the sequence of construction. Mr Brooks explained: "Each section would be individually made up off site, then dismantled for reassembly at the building. But because the timbers were rough hewn and non-standard it was important to know which piece went with which."

Because the beams were pegged together rather than secured with nails, Mr Brooks explained that even today, it would be comparatively easy to dismantle the building and reassemble it elsewhere.

Mr Brooks also pointed out the scalloped pattern on the sides of some of the beams. He said: "That indicated the use of an adze, rather than a saw to cut the timber."

Mrs Goacher discovered several internal lime-washed walls built with oak lathes and daub - a mix of mud and straw. Although the same technique was used for infilling walls for centuries, the composition of the daub changed over time, with horse hair commonly replacing straw by the Georgian period.

Mr Brooks suggested one possible origin for the expression "here's mud in your eye" came from the daubing technique of the ancient builders who would sometimes fling the daub from both sides of the wall to fill in all the gaps, occasionally splattering their co-worker. (Alternative origin theories exist.)

Because, one section of timber was clearly newer than others - though still old - Mrs Goacher was able to determine that although the building looks rectangular today, it had started life as an L-shape, with the missing quarter filled in later.

Similarly, although today, the street facade of the building is straight up and down, inside it was possible to see it had been constructed with jetties, extending the second floor beyond the floor-plan of the first floor to hang over the street. The gap underneath had been filled in later. This was the explanation for the location of a window, now hidden inside an interior wall, that once was on the side of the jetty, when the front of the building was only half the width it is today.

And the experts' conclusion? Mrs Goacher said: "There are elements here that date from the 14th century, and since one of those is not soot-stained like its neighbouring beams, that suggests it was itself a later addition, which means the original building could be even older."

The pair will now go away and seek to find manorial records from the medieval period - when the whole town belonged to the Archbishop of Canterbury - to see if they can find paperwork to support their conclusions.

*The Kent Archeological Society holds its Historic Buildings Conference, Saturday October 12, at Cobham Village Hall in The Street, Cobham, DA12 3BZ.

Debbie Goacher will introduce the conference and there will be talks by David Carder on Kent’s Disused, Ruined and Lost Churches, including St Andrew's Chapel at Boxley, and by Christopher Proudfoot on the Old Rectory at Fawkham, while Andrew Linklater will trace the history of Cobham College from its construction in 1362 to the present day.

Admission is £15. Inquiries to mike.clinch@kentarchaeology.org.uk

Book tickets here.

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