Seven weeks in

Hello again! Actually, we are a lot further into our adventure than the title suggests, but let’s return to the first few weeks of the scholarship and fill you in on some of the visits that you may not have heard about.

Following on from where we finished in my last post we then visited a former scholar and SPAB stalwart Andrew Townsend who was recently appointed cathedral architect to the iconic Tewkesbury Abbey. Andrew brought us to sites which included St. Cyriac’s Church in Laycock, the Church of St. James the Great in Dauntsey, Cirencester Cathedral in the Cotswolds, and St. Peter’s Filkins in the Diocese of Oxford. All these buildings provided us with much to ponder, but most evocative was the visit to Tewkesbury Abbey.

Andrew had asked us to come up with an efficient method of carrying out a survey of the ledger stones which covered the majority of the floor space of the abbey. This involved recording the condition, layout and the memorial inscriptions of each ledger stone – and it also gave us a chance to sit down, sketch and take in our surroundings. We noticed the exposed masonry all around and the bareness of the columns, walls, and the webs of the vaulted ceilings. All of these would, before the intervention of Victorian and nineteenth century restorers, have been plastered in lime. The prolific English architect, Sir George Gilbert Scott (1811-1878) was responsible for the removal of this historic plaster, but he believed he was improving the aesthetics of the Abbey interior. It was during this work that another man by the name of William Morris happened to walk into the Abbey as the labourers were scraping off the historic fabric from the heights of their temporary scaffolding. Morris couldn’t believe what he was seeing and although he had been disturbed by other restoration projects before that day, it was this particular episode which gave him the impetus to set up the Society for the Protection of Ancient Buildings (SPAB).

After Tewkesbury we made our way to another SPAB scholar and architect, Nick Cox, at the empowering Blenheim Palace. Bath stone is the main building material here with Portland stone used where needed as a weathering detail such as in the copings. Analysis of the stone showed that copperace (iron sulphate) had been used for aesthetic purposes historically to patinate the natural honey colour of the Bath stone into a dark brown/orange colour. We witnessed three types of stone repair techniques being used on site, which included stone mortar repairs (sometimes referred to as plastic repairs) where a lime mortar is used to regain the profiles of the original ashlar while providing a protective layer to the historic original fabric underneath. Then there was use of stone indents where only localised stone decay or damage has occurred and thirdly there was full stone replacement where the architect and client have decided that too much of the original stone has been lost, possibly weakening the structural integrity of the wall and a new like-for-like stone is inserted in its place.

Plastic Repairs at Blenheim Palace

Nick then led us to Woburn Abbey in Bedfordshire. Today it is largely a Palladian house but has origins dating back to 1145 when monastic buildings, founded by Hugh de Bolebec, once stood. The Palladian house is a result of the architect Henry Flitcroft in 1747 but there was also additions made by Henry Holland in 1786. The park was landscaped by Humphry Repton in 1802 while Jeffry Wyatt is responsible for the flower houses. From a distance the west front of Woburn Abbey is stunning in its classical proportions although on close inspection of the stone facade a poor finish is observed which doesn’t sit with the building’s overall grandeur. Window cills and matching stone surrounds, quoin stones and bases appear to be out of sync, resting too proud of the main building stone. This unfortunately is the result of many attempts to solve an inherent design weakness in the building. This weakness lays in the choice of original building stone known as Tottenhoe clunch (chalk) stone. The west front of Woburn has much Tottenhoe stone still present, but in the 1980s a ‘dressing back’ technique was used which involved removing the weathered surface of the stone and bringing it back to a more solid facing. The eighteenth century facade profiles have now been lost and the 1980s skin has become weathered – so how does one go about specifying new conservative repairs? Some, in the past, have used Portland stone to replace the badly weathered chalk stone, but this clearly is no match for the colour and texture of Tottenhoe and changes the appearance of the building as a whole. If you specify Tottenhoe as a like-for-like replacement then you run the risk of putting further expense on your client as the stone is sure to decay in the same way in the future. Furthermore if you decide to use full stone replacement do you dress the new stone back to the eighteenth century profile? This new facade line may have to be based on hypothesis. Is this acceptable in conservation terms?

A bit of a conundrum for the Abbey architect who is currently searching for a sympathetic and satisfactory solution.

Next, London was calling as we visited the offices of Alan Baxter and Associates, consulting engineers to St. Paul’s Cathedral for many years now, who took us on a tour of this marvellous edifice. We were taken behind the scenes, through the many concealed passages within the solid masonry walls. We accessed the roofspace looking at the timber roof trusses which are located just above the stone vaults of the internal ceilings of the cathedral. We then took a walk out onto the roof which gave us a panoramic view of the city of London.

After London we were hosted by Philip Hughes (Building Surveyor and SPAB Scholar) at one of his current projects, St. Giles House in Wimborne. This building dates from the seventeenth century and is currently the residence of the Earl of Shaftesbury. The project has a blend of highly sensitive conservative repairs and necessary building restoration works. Proposals include the reintroduction of highly decorative interior finishes which were lost to over-enthusiastic and misinformed twentieth century dry rot removers and the rebuilding of external architectural features such as the north tower and loggia which were demolished in the nineteenth century. Some of the repair techniques used on site are plastic repairs to brick and stone elements of exterior facades, micro-pinning used to repair minor cracks in stone features such as copings, lintels, and reveals, and Helibar used in mortar joints to bridge structural cracking in the brick walls. Between 1740 and 1970 the elevations were rendered in Roman cement but in 1970 this was removed and the brick has been exposed to the inclement weather conditions ever since. In many cases the harder fire skin has been lost through freeze thaw action. It is believed the original bricks were sourced from within the estate and replacements are extremely difficult to come by today. In some situations redundant bricks from the house have been crushed and the brick dust used in the mortar mix for the plastic repairs.

Within the grounds a menacing grotto of about 1750 awaits at the end of a canal perched above a culvert. It was built for Anthony, fourth Earl of Shaftesbury and some have said that it was finished by John Castles of Marylebone while others suggest that a nameless Italian, who never allowed anyone watch him work, was responsible. It performs the illusion of being a spring or water source to feed the serpentine lake. The grotto was previously invisible from the house, hidden by fir trees and yews. Unfortunately, many of these trees have been and will be removed as part of the current landscape restoration appraisal which has found that the existing trees have come to the end of their life and are at risk of collapse. The grotto has a rusticated front of flint and stone, the left door leads you into a type of cavern while the right door is an entrance to a dummy passage. Inside there are two rooms. The first is merely a vestibule to the second taller and wider main room. The entrance to the second room is supported by a gothick arch surmounted with curved branches of dim stone. The main room makes use of natural daylight via several skylights and a rococo iron window. The back wall contains a fireplace which is flanked by two air ventilation grilles either side. The vestibule is decorated with minerals such as flints, spar, quartz, grey granite, coral, felspar, broken mirrors and coloured glass. The ceiling is generally covered in coral decorated branches and the floor with pebbles. The main room is dominated by shell work. The walls come alive with protruding and twisted branches covered in shells. Barbara Jones’s timeless publication Follies & Grottoes (1953) suggests that the designer of the grotto interior may have been trying to create an underground aquarium environment with the first room being “the surface of the reef” and the second room “the bed of sea inside it”. The presence of tropical shells collected from around the world and even the vertebra of a whale give credence to this hypothesis. Either way, the grotto was a luxury that would have taken many years and many thousands of pounds during the eighteenth century to complete. It may have been used for hosting feasts and tea parties for the Shaftesbury’s distinguished visitors. The ambience within the grotto was sure to have been enhanced under candle light as the flames flickered across the decorated interior surfaces. Added to this there were many other fascinating garden building and follies that punctuated this landscape such as the pepperpot gate lodges, sham castle (or towers), hermit’s alcove, Shakespeare’s seat, cascade, pavilion, sham gates, temple and Chinese wooden bridge. Only some are still present on site today. Suzannah Fleming has carried out a study of the estate but she was unable to identify the designer of the landscape. She did however suggest that Charles Bridgeman may have been involved at St Giles.


We then left Wimborne and made our way up to the edges of the scenic suburbs of Machynlleth in North Wales, the location for the Centre for Alternative Technology (CAT), where we were challenged with breathing new life into a neglected lime kiln that was slowly being consumed by Mother Nature.


Under the guidance of the architect and lime specialist Stafford Holmes we tackled the reclamation of this stone slate constructed pit kiln. We also endeavoured to build new slaking and putty settling tanks out of the local stone slate, but alas we were beaten by the constraints of time. After removing vegetation we ignited an initial fire inside the kiln to attempt to dry it out. This was left overnight before we introduced the limestone and commenced the real burn. The limestone we used was chalk as this was all that we had available to burn at the time. We broke the limestone up into regular sizes, weighed them out into 25kg buckets and placed them into the kiln in 100kg layers separated by a 50kg layer of coke. The kindling was lit and the kiln was left overnight to smoulder.

On return the next day we sought to slake one piece of quicklime, but there was no reaction with the water. The heat generated in our kiln was insufficient to cause the limestone to lose all of its carbon dioxide. This most likely was due to the fact that the kiln had been left dormant for so long and also our choice of burning material. Chalk limestone readily absorbs water and it had been stored outside uncovered for over a year, therefore it was far from the ideal material to burn! However, we made do with what we had and it was a lesson in how important it is to select, protect, and prepare good materials. We emptied the kiln, then refilled it with limestone and coke as before and left it for another night over the flames. Fortunately, when we returned the next morning and placed the quicklime into our bucket of water we had a more extravagant reaction. All the quicklime was then slaked and we separated it out into smaller containers immersed in water so that carbonation could not occur. The lime putty was ready to be mixed with sand and turned into mortar to be used for any future works on some grateful historic structure!

Owned by the Prince’s Regeneration Trust (PRT), the Old Duchy Palace in Lostwithiel is a grade 1 listed property. It is a hall that once formed part of a wider complex of buildings that acted as the administrative centre for the domain of the Duke of Cornwall in the late thirteenth century. Towards the end of the nineteenth century the hall was used as a Freemasons’ temple. The purchase price added to the repair and refurbishment costs far outweigh any selling-on price that the client could hope to receive. This is a common problem with so many of our heritage buildings in need of rehabilitation – they are not commercially viable when it comes to reuse. This conservation deficit will need to be covered by grants which the PRT in collaboration with the Cornwall Buildings Preservation Trust are working at trying to procure. Luckily they have already secured significant grants from English Heritage and the European Development Fund (ERDF) which will allow works to be completed. On site we spent a day with stone conservator Sarah Hollowood of Carrek Historic Building Conservation Contractors (www.carrek.co.uk). The structure is built of stone slate and is badly weathered in most places. Carrek are gently defrassing the friable edges with a brush and raking out the mortar joints for repointing. The pointing mortar used was an NHL2 from France mixed with local sharp sand, coal dust and a black aggregate which was used to match coal pieces used in the original mortar. A coat of arms on the gable end was covered in a thick black sulphation. Sulphation prevents the stone from breathing and can lead to decay of the stone underneath. It was decided to use a poultice of ammonia carbonate and sepiolite (clay dust). The surface was well-dampened before the poultice was applied as you don’t want the ammonia carbonate to penetrate the stone itself. Trial areas of the coat of arms received the poultice first and these were covered in clean-film as an extra precaution to prevent drying out. The first application was a weak mix and left for a couple of hours before inspection. When Sarah was confident that the poultice was working and not damaging the stone fabric she then was able to leave the poultice on overnight.


Our next outing was to the town of Ottery St. Mary in Devon with the cob builder, Kevin McCabe. Using materials from his own land Kevin is constructing a new home on a grand scale. The site provides him with cob that is 40% clay and 60% silt. This lays on a stratum of sand which is also beneficial to the mix. However, if you have too much sand the cob will soak up too much moisture which can lead to collapse of the structure. Alternatively using just enough sand will lead to less shrinkage occurring. This is quite the opposite of clay where high shrinkage can occur, but it can also take in a lot of moisture without collapsing. The ratio of sand to clay in this region of Devon is very good which according to Kevin is why there are a high proportion of cob buildings in the area. Kevin had excavated a pit in his future back garden where he mixed the cob with the shovel of his digger. He added two bales of straw and water into the pit also. From the pit Kevin was working he was able to produce about twenty-five tonnes of cob. The cob was then transferred from the pit to another area of the site where he had constructed a concrete slab. The cob was dropped onto this slab and spread out by continuously driving back and forth across the cob. This ensures a well-mixed building material. The cob walls and columns are generally constructed in lifts of about 600-700mm in height using pitch forks to lift the cob into position in tandem with manual stamping and mallets to ensure proper compaction and squaring. Cob building is not an exact science, but it is a proven method of construction with many historic cob building structures still performing adequately to this day.


At Wells Cathedral we again met up with Nick Cox, and he was joined this time by the wonderful Jill Channer, an enthusiastic conservator and stained glass consultant. After a lecture by Jill we took a tour through the dusty back corridors of this eminent building. We observed at close-hand the poor state of the medieval stained glass in the choir east window from the heights of the impressive suspended temporary scaffolding. We noticed how in some places medieval glass had been moved out of its original context and placed in another position on the window during previous repair works. This gave a confused pattern close up but from the ground it was unnoticeable.

We left the cathedral and made our way to the workshop of the glass conservator, Steve Clare. We watched as he meticulously repaired the stained glass from Wells Cathedral which had been carefully recorded and then moved to his workshop a few days earlier.

Finally, during our trip to IJP Owlsworth Conservation workshop with Mick Poynter we visited Hollywell House in Farringdon. We observed as Mick was repairing a decorative grade 1 listed ceiling. The existing plasterwork ceiling is in an earth plaster and appears to have been applied in one coat, but Mick has decided to treat the replacement plaster as a typical lime plastered ceiling and apply the new earth plaster in three coats. The mouldings in the ceiling are pure plaster of Paris. An interesting ceiling and it was worth seeing! We also got to have a go at making door handles and hooks at IJP’s forge which Charlie demonstrates in the photograph below.

Okay that’s it for now, it was another long one and there’s still so much we have to fill you in on!

We have covered a lot of ground to date, from Penzance in the south west of England to the Orkneys off the coast of Scotland, from Machynlleth in west Wales to beautiful Valletta in Malta and yet our journey is not over. Our last and final expedition, which will draw to a close our first six months of the “Bricks and Mortar” Lethaby Scholarship, is a tour of the Emerald Isle. The SPAB have kindly allowed me to introduce my colleagues to my home country.

We are all looking forward to it!

On a side note, one of the benefits of living in the UK at this time is that I got to witness close-hand the inspirational Paralympics games. On Friday the 7th of September I watched my good friend, Mark Rohan (representing Ireland) win two gold medals for hand cycling. We played on the same Gaelic football team together, many years ago, before his terrible accident  left him paralysed from the chest down. The race was an unbelievable experience, very exciting, and an extremely proud moment for us all. Well done Mark and all the athletes from around the world who took part!

Until next time, keep well. Justin

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2 thoughts on “Seven weeks in

  1. I greatly enjoyed your accounts of where you have been and what you have seen and hopefully learnt – you have been meeting up with al the right people| Very interested to read about Woburn. I used to live near there when young and my memory tells me it was scraped back about 25mm in the fifties.It was before I got involved with repair and SPAB etc and thought that it looked splendid. Would I think the same now? Really sad thing about Woburn was the demoltion of Holland’s Riding School and the back of the house which shocked me even then. Good to hear from you, Jim Boutwood

    • Hi Jim,

      Great to hear from you and thank you for your comment. You are absolutely correct, the scraping back method used at Woburn Abbey was accepted as a good practice remedy for many years but as far as I remember it was last carried out in the 80’s. It will be interesting to see how they will deal with the facade in the near future. It’s a difficult one!

      All the best,

      Justin

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