1 10 2 https://d1y502jg6fpugt.cloudfront.net/21127/archive/files/a950e97bf8b4a70acd455e69519f047a.pdf?Expires=1774483200&Signature=A5LpS1XB4eYn7WlJgM-BWYl-G0%7EKP4uBQTrSaT86BByGCFNX1Wd1YfM9DgLg1ux5UNvvtAPw6pcJxR-MlM5xr7WU7r4pHvoHqQzaO-40wkbMoM0qRFUIZOjH%7EIzidqMzGlotk-Kt1Kv7Iq5L5t-l11NU8ORjbGPdq907KFHRTxUh8ERoupJWKaeaxlAqce1hVcs3ilnkw6wXof-%7EUzVBwCwCQUMmfpOvKzlTvXfOBvd83RjR3cZqpH-7RZUbGfqD%7E5omC0TM-hrXh8xGBMTIvMDFkwoscSHSdj0TnOV6AaoCtDBuftmP51Z9DxNaGxhonnhY6PHYuHP9uvQlifONLA__&Key-Pair-Id=K6UGZS9ZTDSZM aa5e5d14c2d4be454b1f4fd5802d666c PDF Text Text A NOVEL TECHNIQUE FOR THE CONSERVATION OF  LARGE TILED PANELS  S. Casey and Robert Turner ACR, Eura Conservation Ltd Introduction This article discusses a new process for carefully removing large, heavy, decorative tiled panels from masonry walls, a process which was adapted from one previously developed for the removal of ‘signature panels’ from plastered walls due for demolition. The technique was applied on an ‘industrial’ scale, over a relatively short time frame, to 68 panels. It involved use of specialist cutting and lifting machinery, co-ordination of a number of large team of conservators, and strict adherence to architects’ and building contractors’ timetables. Late in 2001, Eura Conservation was asked to look at the possibility of saving some signature panels from the shortly-to-be-demolished Manchester Free Trade Hall (FTH). The signatures were in pencil on rendered plaster and were signed by some of the musicians who had appeared in the hall since its post-war rebuild in the early 1950s. A successful technique was developed and the panels are now on display in the Radisson Edwardian Hotel, built on the site of the old FTH. In 2009 Eura was asked if the technique could be modified for use in another project, involving the safe removal of ceramic tile panels from a hospital. The answer was ‘probably yes’, although some development work would be required. The need for intervention Two children’s wards, containing 68 Doulton tiled panels, were due to be demolished as part of a re-development of the Royal Victoria Infirmary in Newcastle. One of the great benefits of ceramics is that the colours often remain as fresh and vibrant as the day they were first created and this is certainly the case with this fabulous collection. Most of the panels depict traditional nursery rhymes and were painted by artists such as William Rowe, JH McLennan and Margaret E Thompson. Similar panels can be found on the walls of the Sassoon Hospital in Poona, India, as well as the Wellington Hospital, in New Zealand, which has recently conserved 18 panels. The Newcastle collection is significant, however, in that it comprises no less than 57 story panels, together with 9 panels depicting rural scenes and 2 text panels showing the names of the wards. There are a further 18 text panels in other parts of the hospital. It is thought to be the largest such collection in the world. The collection is of further importance in that it is a snapshot of the Edwardian age: illustrative of the role played by rhymes and stories in childrens’ education, of attitudes towards the infirm and of social philanthropy. �Figure 1 One of the Doulton nursery rhyme panels before removal The choice of conservation process The traditional approach to the task of removing tiled panels is to cut along the line of grout, freeing each tile from the matrix of its fellow tiles. This ensures that any cracking will be contained and limited to an individual tile. The conservator then prises the tile from its matrix. There are a number of difficulties and risks associated with this process. The technique relies on a minimum gap width between each tile that is larger than the cutting width of the blade, so that the grout might be cut without damaging the tile glaze on each side of the kerf. The chief risk, however, is that the conserver has to attempt by trial and error to prise or lever a very hard, brittle object off a similarly hard underlying surface. Commonly the process brings about cracked tiles. Furthermore, because it separates the panel into multiple pieces, there is also the risk that parts may over time become lost or the orientation of components confused. A different process was developed for the removal of the signature panels from FTH which addressed the fact that as there were no joint lines to cut along, the panels had to be removed in one piece. If a similar technique could be developed for the tiled panels, it should result in reduced irrevocable treatment and increased efficiency. The objective of the new technique would therefore be the removal of an entire panel in one go, with a sufficient layer of cementitious backing retained in place to prevent flexing and separation of individual tiles along the lines of the grout. This was to be achieved using a combination of frontal facing & support and diamond-wire cutting through the entire backing of the mortar matrix. 2 �The new process To achieve the cutting action a continuous loop of diamond-coated wire is mounted on a number of pulleys, one or more being motorised. Between two of the pulleys there is a large span of wire that performs the cutting as it comes into contact with the target material until the cut is complete. Diamond wire is chosen as it is able to saw through virtually any material. As the wire cuts, it is pulled through the structure like a cheese wire. Obviously considerable care has to be taken to ensure that the wire does not come into contact with any of the tiles to be conserved. In Manchester, the signature panels were supported during removal by carefully prefitted mild steel frames. While this technique worked perfectly, the tiled panels in Newcastle are significantly larger. Consequently, a series of workshop trials were conducted on specially prepared ‘mock’ tile panels. These tests were chiefly concerned with developing a means of adhering a rigid surface to the face of the tiles, in such a way that the weight of the entire panel could be borne in tension by the adhesive/consolidant. The adhesive had to be fully reversible, and to cause no adverse reaction to the tiles. The final choice was a 20% solution of acetone and Paraloid B72. It gave a pull-off test value in excess10 kN/m² and was wholly reversible. Figure 2 Conducting a lifting and adherence test On the hospital site, each panel was surveyed and any site-specific requirements noted. The perimeter of each panel had been bordered in recent times with a 50 mm wide pine frame, mitred at the corners, and screwed through into the wall. These 3 �were removed to reveal very many old holes in the tiles and a general thin covering of plaster and paint. This was removed with a proprietary dichloromethane paint stripper. After the surface had been checked for painted plaster repairs (often found on old panels) the tiles were cleaned with acetone. A border was then marked around the outermost part of the panel with a chinagraph waxed pencil. This border provided a safe perimeter for the picture tiles. Any areas of grout that appeared to be missing were then re-instated, to ensure a uniform matrix of tiles. A barrier coat of 20% Paraloid B72 and acetone was then applied with a wide brush to the entire surface of the panel. This was to serve as a removable barrier coat between the tiles and a layer of glass-fibre woven matting bonded with 20% Paraloid B72 and acetone. Small urethane foam pads were placed into position at regular intervals on the surface of the rigid matting once the B72 and fibreglass matting had completely solidified. A 25mm marine plywood sheet, which had been pre-cut to the exact dimensions of the tile panel, was then placed into position covering the tiled panel, with the bottom edge of the plywood resting on two lengths of all-thread, which had been resin-fixed into the wall. The plywood panel itself had also been pre-drilled with a regularly spaced series of 12mm diameter holes. A series of horizontal timber battens was then fastened to the wall, in the same manner as the all-thread. These battens held the plywood sheeting firmly against the foam spacers. The plywood panel was then bonded to the consolidated and protected surface using aerosol polyurethane foam, injected through the holes in the plywood. The timber battens held the plywood panel firmly in place while the foam expanded and cured. Once the foam had cured, the battens were removed and a bespoke aluminium lifting-frame was screwed to the plywood panel. The next stage was to accurately chase four 30 mm wide slots around the entire panel, to a depth of 45-50mm. These slots determined the final size of the tile panel. Meanwhile, sufficient space had to be created in the ceiling above the panel to enable aluminium ‘I’ beam to be placed into a pocket in the wall. The plywood panel over the tiles acted as protection for the panel in this procedure. To allow the diamond wire cutter to operate, a number of square chases, roughly 150mm x 150mm, had to be cut in the wall to accommodate the pulley mechanisms. The machine was now carefully positioned and anchored in place, with the diamond wire resting in the upper horizontal chase above the panel. 4 �Figure 3 A panel covered with fibreglass Paraloid, fibre-glass matting and cushion pads 5 �Figure 4 The diamond wire cutter installed. The panel has now been protected with a plywood sheet Figure 5 Close-up of the cutting operation 6 �Figure 6 A panel has been cut through and is being lowered The initial cuts to seat the wire and ensure it wouldn’t jump out of the slot were accomplished by hand. The machine then cut downwards through the mortar, at a distance of 30mm from the front face of the tiled panel. Once the machine had cut through around 75 percent of the panel, cutting was temporarily halted. A scaffold tower was erected in place and the aluminium beam was placed in position above the panel, supported by the tower and the previously excavated wall pocket. The panel 7 �was fastened by a sling attached to a 500kg swl chain hoist on the beam and to the lifting frame on the panel. The sling was then pre-tensioned to accept the anticipated weight of the panel. Cutting then recommenced and continued until the panel was free from the wall. The panel could then be lowered into a packing case and placed in safe store. The panels after removal The panels were removed from the hospital and transported to conservation workshops. Each panel was unpacked and placed facedown on the bed of a masonry plane. The cementitious matrix on the back of the tiles, which up until now bore the marks of the cutting wire, was now abrasively planed into a completely flat and level surface. This surface allowed the panel to be refastened to another 25mm sheet of plywood which would act as the final display substrate without creating any undue pressure points on the original tiles. The panel was then turned over so the “lifting system” could be removed. This involved unscrewing the lifting frame, sawing through the polyurethane foam with a soft saw, peeling off the Paraloid reinforced glass fibre and removing the remains of the Paraloid. The panel was then mounted in a stainless steel frame containing an internal green frame, designed to reflect the original framing tiles. Other than possibly making aesthetic repairs to 1970’s screw holes, no other conservation treatment was necessary. Future applications of the process This technique was developed to suit a particular set of circumstances. It combined efficiency of labour, relatively low cost, and speed, whilst minimising irrevocable treatment of the objects. All consumable materials were easily sourced, inexpensive, and presented no threats to the object. Neither were there any difficult ethical conservation decisions to be made over the need to cut brickwork and drill chases in the surrounding wall because the building was destined for demolition. The diamond cutting process was lubricated with water and the cutting of chases generated some dust. Both of these potential pollutants were satisfactorily controlled in this situation, but might be less easy in other situations. Further, the success of the technique also relies on the strength of the bond between the glazes and the body of the tile. Therefore the significance of the surrounding building and the exact nature of the tiles would have to be considered before this technique could be safely used on other similar projects, although these issues should be relatively easily resolved. 8 �Figure 7 A panel following completion of the process 9 � Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource Big Stuff 2010 Creator An entity primarily responsible for making the resource Alison Wain Date A point or period of time associated with an event in the lifecycle of the resource 2010 Article An article in a journal or periodical Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource A Novel Technique for the Conservation of Large Tiled Panels Creator An entity primarily responsible for making the resource Shane Casey and Robert Turner Date A point or period of time associated with an event in the lifecycle of the resource 2010 ceramic panel removal tile https://d1y502jg6fpugt.cloudfront.net/21127/archive/files/6fb3d503edea91a57da0eeed8db3e425.pdf?Expires=1774483200&Signature=D%7ECp83rgnlxYdS8PJDox4fL%7En0XlDr4GcAm44KxRsrISRbBN8ITGbneWbi%7Ernu96y9A2DSEwAtM2CIjn0tWtkIqdMnPmZs96M%7ELMj8PaNDVbJQeHWxZ%7E-kDH8cth3xSgQVdi3kft38sUS%7EhBJbjMPWdrs2f6ILmgQq%7EhFcabjBpYMS2LrcsJOtPG69JcnOLQCLCXysuWLJVJ2b74C5Ml9X5aTBiaY3tOD98izcLOwl5KOuuh2FuC8o8CL7hbe72UURILz1X7yptu5SG3Po-7pYc4Kit1z7qOTz0UX1S6cz38%7ElimuKSxlbYgk0Pz21CmTiTdeaLKE4Xe%7EaJ-tmQ2bQ__&Key-Pair-Id=K6UGZS9ZTDSZM 0449f52a4db13c001db538b8cf0327b5 PDF Text Text �Conflict avoidance: Balancing the display needs with the conservation requirements at the Natural History Museum Chris Collins Arianna Bernucci Conservation Unit Natural History Museum �Our Conflicts Display Research Events Estates Finance Specimen �Where? Gallery 30 contains 78 specimens which have been mounted on the wall since the 1920’s. This is the most comprehensive and important collection of Lower Jurassic fossil marine reptiles on display in any museum. The wall also contains many specimens which are actively being researched. The collection contains many historic, type and figured specimens and many of the localities from where they were collected no longer exist. �The project In 2009 the Conservation Unit started a program to resolve a long-standing problem of moisture migration through a south facing wall in one of main galleries at the Natural History Museum. The problem was first observed as a serious mould growth on the MDF surrounds to the specimens. Following detailed inspection of 22 specimens on the gallery wall it was decided to remove 9 specimens from the wall for conservation work and until the problem could be fully resolved. �Accessing the specimens Our initial condition survey was undertaken with a Cherry Picker. It quickly became clear that complete inspection of the specimens was not possible and that we needed better access to them. A decision was made to put scaffolding up across both sets of specimens that were at risk. This was so that the glass could be removed from the front of the specimens and if necessary specimens removed from the wall. �Stages of Planning • • • • • • • • • • Project review (Prince2) Condition Reports Gant chart of work required Full costing of project (to acquire funding from capital bids group) – Loss of revenue (events) Risk from not undertaking work Site Risk Documentation – Scaffolding – Temporary Conservation Labs Establish and set up temporary labs Dates for scaffolding and work in galleries identified and cleared Ensure staff available to undertake work Project work program (adapted throughout project) �Development of Plan Once scaffolding inspection was underway, we were able to revise our project plan and produce a realistic costing for the project. Including 3D imaging (to improve research access) Original estimates were £140K 6 month project �Mould and insects on specimens Mould was observed growing on the surrounds to the specimens (at the west end of the gallery). The humidity had risen in excess of 70%. As there was no air exchange within the gallery, the conditions for mould growth had arisen. An infestation of Book lice and plaster beetle was also observed on all the specimens. �Condition of Specimens Conservation Unit staff surveyed 22 specimens on the wall. Most required superficial interventive work, remedial cleaning (mould and dust) and surface restoration - with scaffolding in place we could work on them on the wall. The largest of the specimens, however, required a complete remount due to instability and deterioration. The specimen is over 4m long and weighs 1.5 tons and was (of course) at the top of the wall. Since the wall and the specimens were extremely damp, it was decided to remove the specimens from the west end of the wall where the problems were the most serious wall. They could then be treated and the wall could dry out. �The Problem? Blocked and overflowing gutters were found to have saturated the external face of the wall. In heavy rain, the shallow gutters overflowed and water cascaded down the walls. The wall is a single 20” block through which the water had migrated into the back of the specimens and then through the specimens. Trapped behind glass at the front of the specimens, the humidity had risen to over 70% RH. �A repeat problem The problem had occurred before! A full survey was carried out in 1989 showing that both the specimens and the wall were effected by damp. A conservation project involving the removal of as many specimens as possible from wall (67) was started. In 1995 the lab completed the conservation of 58 specimens across the entire gallery wall. External repairs were made to the wall and restoration work undertaken on the specimens. It was assumed that the problem was resolved! Cost of this project was an estimated £200,000. Clearly we are keen that this time the problem is fully resolved! �Environmental Conditions in Gallery and behind specimens Environmental monitoring in the gallery indicated that the relative humidity between the glass and the specimens was consistently in excess of 70%. The external gallery space was consistently at a lower relative humidity. Because the specimens were tightly sealed to the rear wall, the lack of any air exchange between the back of the specimen and the wall had led to moisture build up in the specimens. �Protection Prior to removal Prior to removal from the wall the specimens were all protected with Plastazote™ foam. Because the face of the large specimen was very fragile due to the level of deterioration, it was also faced with Japanese tissue and Paraloid™ B72, and then covered with a Wacker™ silicon rubber. �Moving the Specimens The mounted vertebrates are chunks of limestone or shale, mounted in a block of Plaster of Paris, supported in a wooden frame. As such they behave structurally in the same way as large paintings - but fail brittley. The large specimens flex longitudinally and laterally leading to cracking at right angles to each of the wooden frames. Differential movement in parallel sides of the frame leads to shear cracking in the plaster support to the specimens. �Moving the Specimens The museum employed the same external contractors who put the specimens into their current position to remove them from the wall. Once protected (with Plastazote™ facing) specimens were removed from the wall and attached to a sling and hoist system. They were then lowered directly into plastic bags (into which they were sealed) and then moved to the temporary quarantine and conservation lab. �Moving the specimens �Movement of specimen onto work platform �Working on the specimens The conservation lab was not big enough to hold and work on the specimens due to their size and the need to quarantine them during the pest treatment. Space had to be negotiated with front of house and empty galleries were turned into temporary labs for the conservation work to take place. In the end 3 different display galleries were used as temporary labs as we moved specimens to fit in with the gallery exhibition programs. With each move, we worked alongside the move team. �Solving the Pest Problem The specimens were treated using anoxic environments to remove the pest problem. All specimens removed from the wall were sealed into barrier film bags (Escal and Marvelseal). These were purged with dry nitrogen until the oxygen levels dropped to below 0.3%. They were then held at this oxygen level for 30 days. Following treatment no pests were observed. Because the specimens were damp they were used to buffer the relative humidity inside the enclosures for the period of treatment. Both during and after treatment, a trapping program was instigated around them to ensure that there was no insect activity. �Conservation and Processing Work Once the pest treatment was completed, remedial work and cleaning was undertaken on the surface of 8 of the specimens. The largest specimen required remounting. A support structure was built to protect the front of the specimen using Jesmonite™. It was then turned over so that the back of the specimen could be checked and stabilized. Again the move team was brought in to rotate the specimen onto its back. �Restoration of 40140 On inspection it was found that the back of the specimen was highly unstable. It was decided to remove the entire support for the specimen and rebuild it using more stable and rigid materials. The back was also to be built to resist moisture penetration. �Structure of Mount Top Surface covered by hardboard facia. Finished up to specimen with Epopast 1” x 1” batons Void Void Void Void plaster cast mounted on top of cellite panel and Facia Cellite Panel Specimen mounted through cellite panel Securing bolt, all layers adhered with eopxy resin Hardboar d Facia Cellite Panel with Facia X Y Separator layer - paraloid B72/Glass fibre cloth Tuesday, 2 March 2010 Epopast moulded around base of object Cellite Panel �Structure of mount Underside Surface coated with metallic paint finish and then finished with appropriate water based paint Seals finished with epoxy 1” x 1” battons Epopast support for base of specimen cutting through Cellite Panel Tuesday, 2 March 2010 Cellite Panel tensioning strip laid on top of Eopoast and lower Cellite Panel Layer �Restoration of 40140 Following cleaning and removal of the original mount, the specimen was protected using an inert Kevlar mesh which was bonded to the specimen with Paraloid™ B72. This acted as a separator. An Epopast™ support backing was then moulded across the back of the specimen to provide a rigid support to the specimen. Cellite™ Panel (honey-combed aluminium board) was cut and then adhered and bolted across the back of the Epopast™ support. �Turning specimen over �Restoration of 40140 The specimen was then turned over. The front of the specimen was consolidated and restored (Paraloid B72 and glass microballoons gap-fill). A medite ecologique facia was then attached to the face of the surround. The gaps around the specimen were then filled with a reversible fill (Paraloid B72 and glass microballoons) . �Current Position Analysis of the environmental conditions on either side of the wall have shown that the exterior temperature of the wall is very close to dew-point. This means that the wall is consistently close to saturation. High Moisture levels and further salt efflorescence on the wall indicate that the continuing problems are not just linked to blocked gutters. Several specimens have been put back on the wall with RH and T transmitters fitted both behind them, between the wall and the back of the specimen and at the front of the specimen behind the glass. An airspace has been put behind the specimens to attempt to generate a natural air flow across the back of the specimens. The aim of this is to try and move saturated air from the back of the specimens to try and equilibrate the space with the (drier) main gallery space. �Moving specimens back onto wall For a trial period (to December 2010), five specimens were moved back onto the wall. A short stepped scaffold was put in place and specimens were manually lifted up the steps and into position �Conflicts Surprisingly not the finance, removal, movement or installation of the specimens, BUT • Coordination of project across museum • Involving; Front of House (PEG), Estates, Collections Management and external researchers • Events department • Length of Project (as we learned more) • Allocation of staff time! �Conflicts • Resolution of the overall problem (Still on-going). Generating Air flow across the wall • Assessing the risk of damage on a 10 year cycle vs complete resolution of project (cost/benefit) • Negotiation for a space large enough for conservation staff to quarantine specimens and then work on them • Adapting techniques because of the lack of lab facilities • Engaging our estates department to resolve the problem quickly • Engaging non-conservation staff in the project �Acknowledgements • Claire Kelly • Lorraine Cornish • Lu Allington-Jones • Nick Sainton-Clark • Efstratia Verveniotou • Colin Farmiloe • Simon Tilleard • Jonathan Krieger • Amber Composites Ltd. ��� Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource Big Stuff 2010 Creator An entity primarily responsible for making the resource Alison Wain Date A point or period of time associated with an event in the lifecycle of the resource 2010 Article An article in a journal or periodical Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource Balancing the display needs with the conservation requirements at the Natural History Museum Creator An entity primarily responsible for making the resource Chris Collins and Arianna Bernucci Date A point or period of time associated with an event in the lifecycle of the resource 2010 3-D scanning display environment fumigation insect mould mount panel planning removal risk assessment