Conservation: Where do I start?

By Aoife Murphy

The Scholarship is giving us wonderful access to beautiful buildings and crafts all over the UK. It’s difficult to choose a blog topic. Do I focus on a craft or a building or an area or a person?

As an outsider who has not grown up in the UK I have decided to write a little on my experiences and how well set up I think the UK is. How there are amazing funding bodies, sources of information and enough of a population to keep crafts alive.

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SPAB Working Party in Lumsdale, Derbyshire

I have grown up in Ireland and lived in New Zealand for over 6 years. While growing up in Ireland I fell in love with old buildings near my home including an old monastic settlement in St Mullins, Borris House and Duiske Abbey in Graiguenamanagh. While studying engineering I found the most interesting projects for me involved older buildings rather than the building of new ones. Due to a recession as I was just qualifying I looked into conservation but the industry in Ireland was small and doors were firmly shut. I worked in Ireland for a while but as more and more projects went on hold I was forced to emigrate. This brought me to the opposite end of the world. A place dear to me but so far away from family and old friends.

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Works underway at the HLF0funded Landmark Trust House at Llwyn Celyn in the Brecon Beacons, Wales.

In New Zealand I saw churches such as the Sydenham Heritage Church torn down days after the earthquake in February 2011 without the church’s trust or the civil defence knowing. The church was built in 1878 which by UK standards is practically new. However by New Zealand standards it was one of the oldest buildings in the country. There was no proper assessment and no formal applications made. It was an emergency situation however and some unfortunate decisions were made. I have loved my time in Christchurch where I hope I made a considerable contribution to the repair of earthquake damaged homes.

Being on the Scholarship this year has opened my eyes to the conservation industry in the UK. There are many wonderful organisations willing to offer information such as the SPAB, the Georgian Group, the Victorian Society, the Twentieth Century Society, Historic England, the Building Limes Forum and many, many more. There are societies for amazing crafts, fellowships and scholarships to keep the industry alive and very passionate people. It’s wonderful. There are trusts set up to protect buildings, such as the Landmark Trust, as well as smaller individual ones. The Heritage Lottery Fund has managed to step in when the government stepped back to help fund a huge amount of buildings and skills. Their Places of Worship, Skills for the Future and Townscape Heritage grants to name a few have been invaluable. They have made sure that local involvement and learning has been an important part of each application, keeping an interest alive.

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A glimpse at some of the stones to be replaced at Salisbury Cathedral under the Major Repairs Programme that has lasted 30 years. Works funded by the Cathedral Trust.

I have felt so welcome coming in from abroad with little knowledge of how the system works here. I feel that although it is underfunded and that people in conservation are not particularly good at blowing their own trumpet as such, the industry is still flourishing and with so many young people interested it can only get stronger. I think we are moving away from the idea that ‘newer is better’, this can also be seen in the food, cosmetics and clothing industries. We are now seeing that whole foods, natural products and natural materials are returning. I think the conservation industry is seeing this too.

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Scholars Visit Haddon Hall during the Working Party in nearby Lumsdale, Derbyshire

I hope that other countries do look to how it works in the UK and I am delighted to see the likes of SPAB Ireland up and running.

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.

The “Conservation Compass”

By Paul Walters

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Paul Walters brick rubbing at Hampton Court Palace with Emma Simpson

It has been a few months since we embarked on the incredible journey that is the William Morris Craft Fellowship and it has not disappointed! We have visited an incredible amount of sites, varying in architectural style, function and grandeur. However, I have always been just as interested in the ethos of the people working on these sites as I have been in the buildings themselves.

As a small business owner it can get very difficult trying to get the balance right when establishing one’s boundaries to repairing, conserving and/or restoring a building, and having spent a significant amount of time these past few months with a variety of craftspeople and conservation professionals, it is reassuring to know that everyone has such dilemmas. There are a few obvious avenues that affect the ability to carry out works in the manner which is perceived as “textbook” or the “SPAB way”, this is perhaps true north on our conservation compass. On sites, this magnetic pull towards our true north is disrupted by numerous and perhaps inevitable complications that will make us deviate from our path. Perhaps the strongest influence is the client. A lot of clients want to ‘modernise’ a building, to the peril of the character that makes the building desirable in the first instance. But equally detrimental is that of personal ambition of specifiers, architects and craftspeople. We can all get blinded by our own version of doing what’s right, whilst trying to manage what the client wants. Some value some eras more than others, some crafts or work more than others.

Fortunately, one could argue that we’re better off having a compass in the first instance? Knowing where true north is serves us in good stead, regardless of whether we choose to utilise it to its full potential. Its reassuring to know that even the most knowledgeable and experienced people go through similar turmoil when making important decisions, before putting the stamp of our era on such amazing buildings.

Lead theft: a heavy toll on heritage

By Kristian Foster

During our April travels, news reached us of the lead theft at St John the Baptist Church in Inglesham. The significance of this church to William Morris and the SPAB made it a particular talking point, and reinforced how devastating lead theft can be.

There’s the damage of losing such critical protection from the elements, the cost of the replacement materials, the insurance costs and the cost of alarms or additional security. When thinking about replacing the lost material one must consider the compromises to authenticity, detailing, appearance, workability and performance. Though there are alternatives to lead, we’ve grown to really appreciate how wonderful lead is.

Hands-on learning is one of the most rewarding elements of the Scholarship. It imbues us with a respectful understanding of the material, its detailing, workability and the skills of those crafting it. In just the last few weeks we’ve been fortunate to develop our understanding of lead.

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Aoife Murphy, cutting out Code 7 Lead Clips, St Mary’s West Tofts

We enjoyed several days with architect Ruth Blackman and family, of Birdsall Swash & Blackman Ltd, Norfolk. They’ve worked passionately for years to safeguard four empty churches in villages taken over for military training operations in 1942. The Stanford Training Area is accessible to contractors for a few days each year, during the lambing period. The most basic and essential repairs are undertaken. We joined S&L Restoration on the roof of St Mary in West Toffs, with its Pugin chancel.

Here we had the task of cutting strips of code 7 lead to form support clips for the base of a sacrificial valley flashing, preventing roof leakages in the infrequently accessed church is vital. Edges were scraped from clips to promote a clean bond during the hot works. The contractor easily demonstrated how to cut a clip, holding the cutter with one hand and gently pulling the lead strip with the other. We mostly reverted to the force of two hands on the snips!

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Scholar produced Lead Clips to secure the base of the flashing

Ruth organised a demonstration and a chance to core weld on some left over lead. Oxygen and acetylene gasses were combined and ignited to create the welding flame, the right blue colour indicated the required temperature. We lowered the flame onto the lead joint until the weld pooled, then rapidly flicked the flame to the side. We continued to melt the adjacent spot until this spot pooled and lead dripped across to combine with the previous melt. All the time carefully ensuring the flame didn’t burn through the lead below. It was all in the wrist and the timing.

Another week we spent a day with CEL Ltd near Peterborough where we watched the process of sand casting lead. We discussed the health and safety issues of working with lead, the fortnightly blood tests for poisoning and the time off required if lead levels in the bloodwork is too high. CEL had separate changing and shower facilities to ensure working overalls were cleaned onsite, not contaminating the family washing machine. Sinks were highly decorated with the required hand-washing techniques and special abrasive hand soaps.

Discussion also focused on the problems of theft and trusting large suppliers to provide authenticity. CEL began as a single lead worker, evolving to become a main and roofing contractor with the skills to remove and recast existing lead in addition to supplying it. Lead is valued due to its versatility, durability and ability to be recast and recycled constantly. Created using three methods, milled lead, machine cast and sand cast, the lead casters at CEL spend 45 minutes preparing the sand bed before sand casting.

Videos of the processes:
https://youtu.be/WV1CmPcyKVQ
https://youtu.be/sp2EntUNL6k

Meanwhile lead is heated to 400 degrees and recycled lead is added to the furnace. Pure lead ingots can be added to ensure the correct chemical mix, preventing a pour that is too brittle. With the sand bed ready, the slag is removed from the lead, which floats due to lead’s density.

Video of the process:
https://youtu.be/1QMXcZvLGac

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Smooth sand bed ready for casting

Pouring the lead onto the prepared table takes a matter of seconds. The speed of the pour can control the thickness or code of sheet, along with a skim.

Videos of the processes:
https://youtu.be/8sehEh4xUiE
https://youtu.be/iPKpuXxSw1Y

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Lead quickly cooling once cast onto its sand bed

Sand casting allows CEL to provide the required size of sheet to reduce waste, measured cut and rolled after the casting. The cut sizes are weighed to ensure the correct thickness and ensure quality. CEL supply to Clare College, Sandhurst and the Cathedral of Notre-Dame at Reims to name a few.

Videos of the processes:
https://youtu.be/nSrjnO17sxM
https://youtu.be/qk9X9LIGsis

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Rolled lead sheets ready for distribution

In addition to learning about the sand casting, we were also able to cast lead roses and discuss more decorative works. Lead is a versatile metal used in windows and statues such as the urns we noted in our first week’s visit to Hampton Court Palace.

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Scholars’ lead cast roses

With the two visits fresh in our minds we could really appreciate the discussion on the re-leading of the dome at Brompton Cemetery with MRDA Architects and contractors Bolt and Heeks. Here, previous details were being improved with better drip and expansion details to add longevity to the repairs.

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Repairs to the Dome at Brompton Cemetery

Lead was also used to offer drip details in timber frame repairs at projects visited throughout Shropshire with Treasures & Sons contractors, such as the 1640’s decorative gatehouse at Stokesay Castle, protecting impressive carvings.

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Protective Lead drip detail inserted at Stokesay Castle

These detailing issues were explored further in the recent SPAB Repair of Old Buildings Course, covering roofing in general and highlighting the issues of expansion and snow loads potentially allowing water ingress to lapped joints if poorly detailed.

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SPAB Repair of old buildings course, architect Peter Pace’s lecture on roofs

With such a valuable, ancient and versatile material, we hope that thefts do not deter its use or lead to irreplaceable losses or damage to buildings like the Inglesham Church and its paintings. A donation page for the repair of Inglesham Church has been set up by the Churches Conservation Trust.

Scholars on the road again

By Aoife Murphy

As our first month draws to a close we have been thinking about what has jumped out at us the most. We couldn’t actually choose though. This nonstop month has thrown so much exciting information our way.

I have particularly enjoyed trying out the trades. We have had the opportunity to try work in a forge, plaster using materials like wattle and daub, carve lime wood, carve chalk stone, hew timber and rub bricks. This has given me a new appreciation for the detail and skill involved.

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Blacksmithing with Owlsworth IJP

We’ve had a chance to visit well-known beautiful places such as Canterbury Cathedral and Hampton Court Palace. However we got a different view to most people. We got to go up on roofs, behind closed doors and into the workshops.

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Scholars and Fellows at Hampton Court Palace

Every site visit has been unique and interesting for a different reason. The smaller sites such as Brook Hall and Landguard Fort have been fascinating as the work being carried out tries to be respectful to previous reincarnations of the building.

The people we have visited every day are so passionate about their work. It’s a pleasure listening to their stories. My favourite topic is how they have fallen into conservation. Everyone has a unique path into the area. There is no direct route. You have to seek it out.

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Aoife woodworking

For the first two weeks we got to spend a lot of time with the Fellows. This is something I feel should be encouraged as much as possible. The different knowledge and points of view open great dialogue and discussion.

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Find our updates on Instagram at #spabscholar2017

Celebrating 30 years of SPAB Fellowship

This year marks the 30th anniversary of the SPAB Fellowship. Founded to nurture craftspeople at the beginning of their career and introduce them to building conservation whilst also allowing them to develop their own craft. This unparalleled experience encourages hands-on learning and a passion for building conservation. We’ve trained over 100 Fellows, from all over the country, working in many different trades. SPAB Fellows are some of the most dedicated and knowledgeable craftspeople, and work on some of the most important buildings in the UK.

We’re celebrating with three videos featuring some Fellows from the past 30 years. Last autumn we caught up with them at their place of work: Alex Gibbons (cob builder, 2014 Fellow), Helen Bower (stained glass conservator, 2001 Fellow) and Ray Stevens (stonemason, 1987 Fellow).

 

Ray Stevens, stonemason at Calke Abbey

 

Alex Gibbons, self-employed cob builder based in Cumbria

 

Helen Bower, stained glass conservator, filmed at York Glaziers Trust

 

Read more on the background of the Fellowship in the spring 2017 issue of the SPAB Magazine, reaching SPAB members by mid March.

Scholars and Fellows: Where are they now?

Harry Wardill, 2011 Scholar and structural engineer, writes about the cultural preservation charity he set up in Myanmar. This article first appeared in The SPAB Magazine, autumn 2016. The SPAB Magazine is a benefit of SPAB membership.

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Harry Wardill (left) with Philip Gaches, a UK-based master plasterer

The city of Yangon (Rangoon) in Myanmar (Burma) is an enchanting place – whether it’s the smiling faces, tropical climate, bustling street life, gilded temples or crumbling British colonial architecture that appeal, it seems to be a place that captivates many. For me it is the perfect mix of all of these things, united to create something even greater than the sum of its parts. I came here at the end of 2014 to set up the cultural preservation charity Turquoise Mountain in Myanmar, one of the initial aims being to support the local Yangon Heritage Trust by delivering an exemplar renovation project – focusing on aforementioned ‘crumbling British colonial architecture’.

I arrived at a key moment in Myanmar’s history – what we now know to be on the path to democracy led by the Nobel Peace Prize Laureate and former Oxford resident Daw Aung San Suu Kyi – but then it was a much less certain time still under the former quasi military government. With this opening up of the country comes the desire, and increasing economic means, to develop. And it is this rapid and unregulated growth that poses a threat to the unique heritage and character of the city.

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491-501 Merchant Street before repairwork

Work began on site at our first project, 491-501 Merchant Street, in July 2015 and was completed in April of this year. This building was chosen because it embodies so many of the qualities and challenges of properties in the Downtown. It is a prominently placed, elegant colonial building with grand internal spaces and vibrant life in and around it, but it was in a very poor state, and littered with unsympathetic additions. The residents originally approached the Yangon Heritage Trust because the building was under threat of demolition – and they didn’t want this despite promises of space within a shiny new building proposed by an opportunistic landowner keen to realise monetary value from his site.

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Hand-drawn survey drawing of the front elevation of 491-501 Merchant Street by local architect Hla Thaung

The community, like the Downtown, is a real mix – from a Hindu teashop to a Muslim photocopier stall, from a spacious apartment with a family of 4 to a more compact place, home to an extended family of 20! To add to the excitement, everyone stayed in residence throughout the renovation works – even when the roof was stripped back to the original iron wood trusses. There were weekly community meetings, and as you can imagine, never a dull moment, but everything skilfully and diplomatically overseen by the ever-smiling Ko Ko, my dependable site engineer.

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Carpenters installing decorative eavesboard

To address the skills and knowledge shortage in relation to building conservation, a programme of training was delivered throughout the build – both day-to-day on site, and at special workshops open to the wider building community. The standard of these was set when master plasterer Philip Gaches was flown in from the UK for the first two-week workshop, which covered the relevant skills needed to repair the flat and decorative lime based plasterwork. Given this was the first time this kind of training was delivered in Yangon it was difficult to predict how it might go. Thanks to Philip’s mix of skill, rigour, adaptability, and sense of humour, in conjunction with great local support and the willingness to learn, a huge amount was achieved in a relatively short time, and it provided the model for future workshops. Most importantly, it meant that the craftsmen had the skills and knowledge they needed to get started on repairing the internal and external plaster elements – from in situ running of mouldings to hand modelling the acanthus leaves of Corinthian capitals.

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Repairing the roof

Future workshops covered topics such as conservative repair of architectural timberwork, clay tile roofing, and brickwork conservation to name a few. The base skill level of the best craftsman is very high- often issues exist around methodology, inappropriate materials, a tendency to over-restore or simply just not getting the right people for the job.
The rich living heritage within the building was recorded through photo portraits, oral histories and a documentary made entitled ‘Under One Roof’, which gives fascinating snapshots of Myanmar’s torrid history over the last decades, told through the voices of the residents. All this culminated in an exhibition that was held in part of the building, and a three-month programme of events aimed at getting as many different audience to engage with the project as possible – from traditional puppet shows for school children to a lively two day heritage themed debate in partnership with the Yangon Debate League.

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The oldest and youngest residents in the building

The project has gained the attention of the new democratically elected government and the public, secured the building, and laid the foundations for a local skilled conservation construction industry. In very simple terms, it has shown people that, with a little effort, Yangon’s historic buildings can be made fit for modern living – and what’s more, they have a beating heart.

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491-501 Merchant Street after repairwork

Watch the documentary ‘Under One Roof’ on Vimeo
Follow Turquoise Mountain in Myanmar on Facebook

Could you be a SPAB Scholar or Fellow?

We’re now searching for SPAB Scholars and Fellows for 2017. Apply for the Scholarship programme and the Fellowship programme by 1 December.

We welcome Fellowship applications from craftspeople employed in the repair of historic buildings on site or in workshops and studios. Candidates must have completed their apprenticeship and demonstrate a high degree of competence, as well as an enthusiasm to engage with other trades and disciplines. Past Fellows have been stonemasons, stained glass conservators, blacksmiths, carpenters/joiners, bricklayers, leadworker and plasterers.

Our Scholars are architects, surveyors and engineers who have completed their college-based training (e.g. RIBA Parts I & II for architects), ideally with a few years experience in their field. Applicants must be enthusiastic about old buildings and willing to travel the country for this nine-month countrywide conservation tour.

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A word from this year’s Scholars and Fellows:

Triona Byrne, structural engineer
We’re over halfway through the scholarship at this stage and some of the highlights for me have been the traditional practical skills we have been given the opportunity to try. Thatching, earth building and dry stone walling were among my favourites – it’s been brilliant to have the opportunity to learn about things I’ve always admired from afar without a clear idea of how they are actually done. The different approaches to conservation we’ve come across have been really interesting to dissect and debate. They are helping me to shape my own conservation philosophy.

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Triona mixing lime mortars at Duart Castle

Dec Cahill, building surveyor
As we fly into the fifth month of the Scholarship we’ve been to all sides of the country, as well as a great trip to Italy with the Landmark Trust to study Palladio’s Renaissance revival of classical architecture. Along with the various working parties at Great Croxley, Balmerino and Greatham, I have thoroughly enjoyed our time in Cumbria drystone walling and visiting my hometown of Manchester!

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At Winchester Cathedral

Thom Evans, stonemason
It is the overwhelming kindnesses shown to us by the hosts that has really amazed me. The educational value of the fellowship is well known within the industry but the friends you make, and the fun you have is difficult to explain to outsiders.
Whether you’re being welcomed by a host for a week – Marianne Suhr, Douglas Kent- or just for a few hours we’ve been made to feel at home. It’s this attitude that has allowed us to ask questions freely and not to feel foolish when we don’t know certain things. A big thanks to anyone who has already helped, or hopes to in the future.

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Constructing a newbuild clay dabbin structure in Cumbria

Lizzy Hippisley-Cox, stained glass conservator
Although we are only seven weeks in, the Fellowship has already had an enormous impact on the way I see building conservation, and the way my work fits into the grand scheme. I am getting a much better understanding of other traditional techniques and materials, and the skills involved in mastering them.

The highlights for me have been instances where we have walked around churches (large and small), taking in the detail. There is so much to be said for taking time to look at the historic fabric together, and then talking about what we see from each of our different professional perspectives. It is the process of discussing what has happened to a building, and what the potential outcomes will be over time that has taught me the most so far.

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Declan and Gethin trying fresco painting

Stone in Wales

by Thom Evans

Something I often hear is that Wales is a country full of hidden gems; I was born and raised in Cardigan Bay, and still live and work there as a stonemason, and cannot argue with this description. I can honestly say that rarely do a few months pass without me stumbling upon a little-known historic building full of delightfully untouched charm. However during my Fellowship year I am coming to realise it may not just be the buildings themselves whose fantastic value is underappreciated but also the people who serve them.
I began the third block of the Fellowship (a time of study away from the other Fellows to pursue our individual interests) by meeting with Dr Tim Palmer a retired senior lecturer at Aberystwyth University whose current charges include being a consultant in Architectural Geology, ex-secretary of the Welsh Stone Forum and enthusiast/font of knowledge on all things stone. The extent of the knowledge Tim was able to impart is far too large to do justice in this blog but I would like to concentrate on one revelation that has caused me to re-evaluate my thinking.

Strata Florida

Strata Florida

Many surviving medieval buildings, whether fortified or ecclesiastical, along the south and west coast of Wales (as well as the east coast of Ireland) appear to contain a certain amount of Jurassic limestone that to the untrained eye could be described as Bath stone. I have encountered this stone, often used for carved detailing, and it had left me somewhat perplexed. Whilst I was often able to discount it as being Bath stone, I had regularly considered it to be Doulting- a hardier more crystalline limestone from Somerset still used today. I often questioned whether this out of place limestone was contemporary to the original medieval fabric, as it appeared not to have weathered as much as one might expect after the ravages of time in excess of 600 years. I suppose, also, I associated the widespread use of the Jurassic limestone in Wales with the Georgian and Victorian era and wondered whether these apparent anachronisms were interventions at this stage. The work of Tim and the Welsh Stone Forum has however been able to settle this little riddle for me.
They have identified this esoteric stone as being Dundry. A non-oolitic Jurassic limestone quarried from Dundry-Hill, just south of Bristol. Whilst it shares many similarities with Doulting such as its age and non-oolitic formation it appears to be significantly more durable. The geological reason for this is explained in detail by Dr Palmer in various papers, but in simple terms the sea lilies whose decaying matter make up the sediment of this stone are Echinoderms and define the dense granular quality of the stone.

Strata Florida

Strata Florida

It is believed that quarrying for Dundry had reached natural conclusion around 1540 when the supply of the best quality beds was exhausted, although a brief revival between 1850-1910 yielded some inferior quality stone. As well as being used extensively for external masonry it was used for numerous fonts, which were often carved in a generic style and shipped across the south west.
So it is easy to understand why this durable freestone which was close to the river Avon, and therefore the Channel, coastline and trade routes achieved ubiquity in its heyday and can still be found now at sites such as Llandaff Cathedral, Chepstow and Newport castles, round to the Bishops Palace in St David’s and as far north as Strata Florida and Aberystwyth Castle. The extensive research and investigation that Dr Palmer and his colleagues at the Welsh Stone Forum have undertaken to highlight the importance of Dundry to medieval masonry should be lauded.

Strata Florida

Strata Florida

The Fellowship has really made me realise that conservation is a collaborative effort. Whether it’s the communities that campaign for funding to protect their beloved landmark, the volunteers that brave the elements to maintain their churches, or the enthusiasts who help us better understand the materials we use.  Many people work away at their own personal interest or profession and rarely get the recognition they deserve. Without them the work we practitioners carry out on site lacks cohesion, and we should be thankful.

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.