Trowbridge War Memorial JN 12045

Transcription

1 Trowbridge War Memorial JN Treatment Report September 2012 War Memorial Report prepared for Wiltshire County Council CLIVEDEN CONSERVATION WORKSHOP LTD HOME FARM AMMERDOWN ESTATE KILMERSDON BATH BA3 5SN T: +44(0) F: +44 (0)

2 TREATMENT REPORT Cliveden Conservation Workshop Ltd Job No. Issue No. Description Issue Date Final Report September 2012 PROJECT SUMMARY REGION: LOCATION: OBJECT: MATERIALS: DIMENSIONS: REPORT WRITTEN BY: Somerset Trowbridge Park Monument Bronze, limestone, cement Approx. Statue 2.40 metres x pedestal 3.5 metres Tracy E. Jeffreys

3 TABLE OF CONTENTS TREATMENT REPORT Introduction Description Treatment Treatment Methodology for the Bronze Soldier Treatment Methodology for the limestone pedestal Additional Treatment Condition Further Recommendations PHOTOGRAPHIC RECORD... 9 APPENDICES... Error! Bookmark not defined. CONDITION CODE SUMMARY... 14

4 TREATMENT REPORT 1.0 Introduction Cliveden Conservation was commissioned by Wiltshire County Council, to restore and conserve the Trowbridge Park War Memorial. It was repaired in accordance with the Condition Report prepared in April 2012 by Cliveden Conservation. The memorial, which was unveiled on August 13, 1921 commemorates the 289 servicemen who lost their lives in the First World War. In 1946 an additional roll of honour was placed on two bronze plaques in remembrance of the 102 servicemen who gave their lives during the Second World War. 1.1 Description A limestone pedestal supports a bronze soldier in full battle dress standing at ease. The sculpture is signed by the artist PG Bentham RBS and the cast was produced and recorded by the Morris Singer Foundry in The contemporary pedestal is raised on a paved stylobate and is flanked at the base of the monument with a pair of cast concrete tablets /stele that are decorated in low relief with the customary regimental insignia. Currently, there is no official documentation available regarding any remedial work or any maintenance including the alterations made to the memorial in Treatment The approach was to, only where necessary, to repair and stabilise the condition of the bronze sculpture and pedestal. This involved removing

5 where possible the extrinsic and extensive copper oxide staining from the monuments stonework. By patinating the bronze, the sculptures bronze was given a passive layer and is returned to a more unified colour while at the same time retaining the surface character of the natural patina. It is not intended that the bronze is returned to the artists pre-determined artificial patina as this would require the removal and as a result the total loss of the established natural patina. There was no intention to remove the existing naturally formed stable patination but only remove active corrosion and build on the protection of the bronze and its existing natural patina. As discussed, the colour of the bronze was altered in keeping with the previously restored Rolls of Honour. An application of a selected chemical patina recipe was worked over the clean and tempered bronze thus creating a passive and evenly toned surface. Given the range of colour and variation on the sculptures surface, to create a totally even chemical patina would result in excessively darkened surface. Slight variations of brown and the retention of areas of very dark green are considered acceptable as the overall effect is one of visual unity of colour. The final preservation coating and wax treatment was specified based on the exposed location of the monument and guided by the absence of a current maintenance programme. 2.1 Treatment Methodology for the Bronze Soldier A primary wash using a power washer with a fan nozzle wand (used at an extended distance of 120mm from the bronze surface and not exceeding a maximum PSI of 800) removed all surface detritus both from the pedestal and bronze. The cast concrete stele were given a general clean together with the principal inscription and the four bronze Rolls of Honour. After washing the bronze was heated and thoroughly dried before the continued removal of corrosion products and any residual wax coating by solvent cleaning using a combination of (1:1) Acetone and Ethanol with surfactant. Concentrated areas of active corrosion were identified and a localised chemical cleaning treatment using the chemical reagent di-sodium

6 EDTA in deionised water was applied with cotton swabs and removed with deionised water. The bronze plaques conditions were found to be stable and recently restored and so did not require any additional patina work. On completion the sculpture was thoroughly washed to remove trace residue (1:1 Acetone & deionised water) and then heated until completely dry before a thin layer of a photo-stable clear acrylic coating with the corrosion inhibitor benzotriazole was applied to all the bronze elements. The bronze surface and structural integrity of pins and bridges were checked. Weep holes were cleared and water traps and pitting or areas indicating metal fatigue were discreetly capped using metal epoxy resin. Minor metal epoxy fills and repairs were made to an open fissure within the rifle butt and water traps between the garment folds along the proper left upper torso were discreetly filled to allow a successful run off. Repairs were colour matched and in-painted with stable earth pigments suspended in the chosen clear acrylic coating. To complete all the bronze elements received a final treatment of two protective layers of Microcrystalline Wax. 2.2 Treatment Methodology for the limestone pedestal All loose friable debris was removed with bristle brushes from the stonework. Prior to treatment the adjacent bronze panels and untreated stone were protected at all times using polythene sheet cut and taped to prevent electrochemical reaction on the bronze or on the unaffected calcareous stone. After testing for suitability, a chelating agent buffered to a ph of 8.5 was introduced to remove the precipitated copper oxides from the stained sections of stone surface using a paper and methylcellulose poultice. To summarize, the areas were pre-wetted and 5 applications of poultice were made to the staining and allowed to dwell for 8, 6, 4, and 2 hours respectively over a period of 8 days. The sections were

7 thoroughly washed between applications to remove all detritus and limit the stones exposure to the chemical reagent. Failed joints and areas of loss were removed and re-pointed & mortar repaired respectively with a sympathetic hydraulic lime mortar. To offer the stone surface a protective sacrificial layer and aesthetically improve the stonework s general appearance two coats of a casein and lime-bound shelter-coat were applied to the stone, worked in and actively developed in vulnerable weathered areas, notably the pedestal die and plinth. A detached fragment of spalled stone located on the North East midsection of the tier steps was repaired and reset. A stainless steel dowel was drilled (4mm x 50mm ) into the fragment and step and set with polyester resin. Minor losses were repaired using a suitable hydraulic lime mortar & hairline fissures injected with a hydraulic grout. 3.0 Additional Treatment Additional work included the introduction of a fixing arrangement which would level the foundation and offer further support for the four most recent Portland stone memorial markers. The centre position and height of each corresponding stone memorial was lined out and a firm compacted base layer of coarse aggregate 100/150mm depth) followed by fine sand (depth 50mm) and a base foundation stone laid (D 40 x 350mm W) with a 6mm dowel core drilled through its centre. To improve the stability and prevent creep, the markers were secured with a 6mm x 640mm dowel set into and through the centre drilled foundation stone. A nut and washer were used to arrange and lock the 115mm length required for the stainless steel dowel to be set into the drilled underside of the marker to a depth of 115mm A general clean to the improve the overall appearance of the surrounding area and including the base of the monument was conducted using a power washer with a fan nozzle wand at an extended distance of 120mm from the paved stone surface and not exceeding a maximum PSI of 800. This removed the accumulated biofilm and growth from the stylobate, steps and paved entranceway.

8 4.0 Condition In general the monument is currently in excellent condition and at this point requires no further treatment. The current stability code is a reflection of the variable and therefore unpredictable conditions that outdoor statuary is subjected to. Photo oxidation and general weathering limit the life expectancy of both the protective coatings. The optimum life of the acrylic protective film if regularly maintained is 8-10 years. Without a sufficient maintenance programme the coating can be expected to need replacing in approximately 5 years time. The estimated life expectancy of microcrystalline wax is 1-2 years with its functionality reduced to below 30% for the second year. Condition Code Summary Stability ii (i stable; iv highly unstable) Condition B (A excellent; D poor): Treatment priority 1 (1 no treatment; 4 urgent) 5.0 Further Recommendations To prevent further cyclic corrosion regular maintenance is essential with outdoor statuary. The memorial will require annual monitoring and a bi -annual maintenance programme to replace the protective wax coating. The stonework will benefit from regular cleaning

9 6.0 PHOTOGRAPHIC RECORD Before primary wash Before patination. After patination and the application of acrylic coating.

10 Patination in progress After final Patination, coating and wax

11 Cleaned Stele mid treatment. Final surface after conservation treatment. Prepared Marker bedding stone with dowel

12 Images show the progression of Sequestering the copper oxides from the stones surface Final complete with shelter coat

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14 CONDITION CODE SUMMARY STABILITY (i-iv) i Stable Condition not expected to deteriorate within the next 10+ years ii Potentially unstable iii Unstable/Steady deterioration: iv Highly unstable: Condition not expected to deteriorate within next 5-10 years Change in condition likely to be evident between 1 5 years Change in condition likely to be evident within 1 year CONDITION (A D) A Excellent B Good C Fair D Poor Little or no damage evident Minor amount of damage and/or loss of original and added material, or with light discoloration or accretions. Noticeable damage and loss and appears disfigured with visible accretions. Considerable and/or significant loss of original or added material or major damage/breakage or disfigurement. May be endangering other objects and surfaces. TREATMENT PRIORITY (1-4) 1 No treatment Conservation treatment not required beyond routine maintenance. 2 Desirable Conservation treatment desirable but not necessary to ensure the long term stability of the object. For instance, conservation treatment may be required for curatorial reasons. 3 Necessary Conservation treatment necessary to avoid further deterioration, loss or undesirable strain on an object and/or loss of significance (evidential or artistic value). 4 Urgent Conservation treatment required to prevent significant deterioration in condition of object and/or loss of significance (evidential or artistic value). This may include structural vulnerability, risk of total loss of entire object or part of object, or risk of accident to visitors/users.