Stop. Look. Listen.

by Lilian Tuohy Main

As we enter the third month of our conservation tour, a theme that continues to arise is the importance of observing before acting.

A unifying trait of historic buildings is their numerous ‘unknowns’. It is this intangible mystery that often makes a place compelling. However, for carrying out repair works to such buildings, the importance of knowing their history, and as much as practically possible about their existing fabric and condition can not be underestimated. Without fail, investing time in the early stages of a project proves to be in the best interest of the building and also results in more economic and time-efficient outcomes, as on-site ‘surprises’ are greatly reduced.

As Scholars, we spent two days surveying 47-49 High Street, Eton, affectionately known by locals as ‘The Cock Pitt’. Here we were set the task of surveying the principal frontage to the High Street, which appears to have been constructed in the first half of the 15th century, and it has been altered and extended on numerous occasions since, most notably in the 19th century.

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West Elevation view of 47-49 High Street, Eton

 

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Drawing up of the High Street elevation, which retains much of its 15th century character

As with any building of it’s age, 47-49 has many interesting and unique features. One that has continued to evoke a reaction is that of the knuckle bone floor at the eastern end of the site. The building was leased by John Rayne, a butcher, before 1551, and another butcher, William Russell also occupied one of the cottages in 1660 (HER Monument Record MRM16551). The floor may have been laid by either of these men – the arrangement being a typical feature of butcheries where bones were not in short supply, and the gaps between bones allowed blood to drain away (The Cock Pitt’ 47-49 High Street Eton, Heritage Statement, August 2015, Built Heritage Consultancy). In the 1930s, nos. 47 and 48 High Street were tearooms called ‘The Cock Pitt’. Allegedly the name was inherited from speculations in the 20th century that the vertebrae floor was a survival from a medieval cockpit, i.e. a venue for cock-fighting.

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Knuckle bone floor – the floor of sheeps’ vertebrae in an outhouse at the eastern end of the site. (Image by Kristian Foster)

Spending time on the busy High Street with tape measures and sketch books in hand, we were greeted by countless interested locals, thrilled and intrigued to know of future happenings to the building, now dilapidated and in need of repair.

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Surveying the timber frame. (Image by Kristian Foster)

When surveying the timber frame, all measurements were taken in imperial. The investigations and recording showed that the building had been rebuilt after having a Georgian or Victorian shopfront added, and that there was a steel beam hidden behind the jetty and sections of contemporary, hard cement render.

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Scholars conducting the hand-measured survey on-site

Timber expert Daniel Miles, mentored us over the two days spent at the building. Through observation and survey we identified evidence of a previous arrangement of a pair of half-Wealdens (a typical medieval timber-framed hall plan). With time, similar discoveries will, no doubt, come to light.

To be granted this time to look with and listen to knowledgeable craftspeople and professionals is proving to be an invaluable experience. The process of taking the time to look carefully and considerately is something we will take forward with us, as we continue the fortunate task of caring for such interesting and treasured buildings.

Building Limes Forum

By Declan Cahill
Earlier this year I wrote a blog post on the wonders of lime which outlined a period on the Scholarship where we were beginning to understand the historic use of lime. Since writing that post, we have travelled across most of the UK and met a wide range of people who are involved in the repair and conservation of historic buildings. On saying our thanks and goodbyes, a common question was repeated: “Are you attending the Building Limes Forum in September?” As the conference has now become a well-integrated part of the Fellows’ and Scholars’ programme we were pleased to hear that we would get the chance to catch up with so many people we have met along the way.

BLF Delegates at St. Georges Hall

BLF Delegates at St. Georges Hall

The Building Limes Forum (BLF) is held annually in September and brings together a variety of people from across the UK and further afield for a three day conference on the use of lime in it’s different variations. The conference was held in Liverpool this year and included a programme of presentations, demonstrations and site visits, as well as the annual general meeting of the BLF. I was particularly interested in two topics that were discussed throughout the presentations and demonstrations: hot lime and how our use of naturally hydraulic limes needs to be questioned.

The conference was opened by Stafford Holmes, who presented a talk on “The Delight of Diversity”, giving everyone a reminder of the different geological limestone strata across the UK, and how both earth and lime have played an integral part in the construction of our historic buildings. The first talk on hot lime was given by Roger Curtis, technical research manager at Historic Environment Scotland (HES). He gave an insight into the research being lead by HES into hot lime mortars. I think it is important here to include Roger’s definition of hot lime in their research, that is “quicklime, being mixed on site with aggregates, often gauged. Using a traditional additive (or pozzolan) where necessary, using the material warm, cool or mature and for building, pointing or harling purposes.” Roger gave an overview of the past and current research being undertaken and the four studies that are due to be published in Spring 2017, these being:

Historic Examples of Hot Lime – Tom Addyman
Recent Examples – Craig Frew and Bill Revie
Historic text Extraction – Nigel Copsey
Consideration in the specification of Hot Mixed Mortars – Ros Artis

There is also going to be a database set up for the analysis of lime mortars. This was fully introduced by Anne Schmidt later in the conference. Roger also highlighted that there will be a hot mixed lime mortars seminar in December 2016

Triona mixing lime mortars at Duart Castle

Triona mixing lime mortars at Duart Castle

Roger’s talk lead nicely into a presentation by Nigel Copsey on his research of old texts on lime mortars. His research has highlighted how earth and lime have historically been used in tandem with one another, and how historically mortars would be mixed hot, most commonly using the common or ordinary method of mixing. Roger’s analysis has covered the continent and has included texts from France and Spain that had never previously been translated.

On the Saturday, the conference covered current research into hot lime by Alison Henry of Historic England and the development of mixes for exposed historic buildings by Lucie Fusade at the University of Bath. Cristiano Figueiredo, also of the University of Bath, presented his analysis on how fit for purpose BS – 459-1:2015 is in a conservation context. Sarah Scammel, another speaker from University of Bath, presented her research into the impact of calcite aggregates on the properties of air lime mortars. All of the talks were deeply insightful but have pointed towards how we are under-using quicklime and overusing natural hydraulic limes without really understanding their strengths and properties, and what boundaries the British Standard gives. This research will hopefully further our understanding of lime mortars in their different states and how they act with historic building fabric.

Mixing quicklime using the common or ordinary method

Mixing quicklime using the common or ordinary method

Sunday morning of the conference gave an overview of the various activities of building limes forums around the globe, as well as introducing next years location for the conference, Trondheim Cathedral, Norway between 7-10 September 2017.

The presentations of the conference were closed by David Wiggins, a structural engineer who has researched into lime mortar and sacrificial weathering. David covered the primary decay drivers of lime mortar, frost attack and salt crystallisation, and how the pointing mortar is a functioning aspect of solid masonry construction, actively removing moisture and salts from the wall. Crucial to the pointing mortar’s function is the free lime content that makes the mortars sacrificial. This is something that natural hydraulic limes do not have but a hot mix produces a mortar with a high free lime content.

The conference was a great weekend to learn about the current research and practise that is ongoing and being applied in the effort to repair and conserve our historic buildings. On behalf of the Scholars and Fellows, I would like to thank the Rathbone Foundation for funding the bursary that allowed us to attend the conference and hope that they will continue to support the Scholarship and Fellowship programmes in the future.

More information about the BLF, the 2017 conference and the upcoming Hot Mixed Lime Mortars Seminar & Workshop on 20 October.