HC1168 Charterhouse Railings Report - Islington

Charterhouse SquareRailing condition and repair requirements

Produced for: The Charterhouse - Tom Hobson

Prepared by: Matthew Boultwood

Date: 18 March 2016

HALL CONSERVATION LTD 36 SHREWSBURY LANE, SHOOTERS HILL, LONDON, SE18 3JF TEL: 0208 855 8567 EMAIL: [email protected]

WEBSITE: www.hallconservation.com

mailto:[email protected]

http://www.hallconservation.com

mailto:[email protected]

http://www.hallconservation.com

Contents

The information contained in this document belongs to the Charterhouse and Hall Conservation Ltd. The copyright of this document is the property of Hall Conservation Ltd and cannot be

communicated to a third party without written permission from one of the Directors.

Hall Conservation Ltd. shall not be liable for any loss or damage arising from any of the recommendations in this document being carried out by anyone else.

Introduction 3...........................................................................................................................History 3...................................................................................................................................Description 4............................................................................................................................Condition 10............................................................................................................................Conservation Proposal 12........................................................................................................

1. In-Situ Repairs 122. In-Situ Decoration 133. Modification 14

Photographic Record 15..........................................................................................................

HALL CONSERVATION LTD Registered Address: 36 Shrewsbury Lane, London SE18 3JF Company Reg. 06492127 VAT REG. GB 918 6848 74 Directors: B. Hall ACR A. Hall 2

Introduction The Charterhouse Square is a private green area situated in Smithfield, London. This land is owned by The Charterhouse almshouse and maintained for the benefit of the residents. The land has been enclosed since 17th century with a variety of walls and railings. The square is currently 1

enclosed with approximately 250m of iron railings.

This report predominantly deals with the railings surrounding the square although a condition record has also been made of the two roadway gates to the south side. See Appendix A.

History The square was originally enclosed with various fences, until around 1742 when residents levied the government for an act of Parliament to enclose and maintain the square. At this time the square was probably surrounded with plain railings on a low wall, which were replaced with iron railings in 1825. These however were lost to the war effort and the current railings were installed in approximately 1950.

“Iron railings and small gates replaced the old fence round the square in 1825. Apart from on the south side, where they were set back when the roadway here was widened in 1873–4, these railings survived until 1942, when they were removed for salvage. They were replaced during the restoration of the garden in 1949–51 with railings supplied by Bayliss, Jones & Bayliss, of Cannon Street. In this restoration the diagonal path connecting the north-east and south-west corners was not reinstated. … In 1960 the railings were reset on new alignments, when the roadway round the square was enlarged. The present planting arrangement of the square goes back in some measure to 1853 when the old trees were replaced. Some of the existing plane trees may date from that time.” 2

The carriageway gates to the southern side of the square are the remnants of the older iron railings, although they are later additions, added to the square in 1874.

“The gates at the ends of the west and south sides were erected in 1874 at the expense of the City Corporation, in order to close off the parts of the square not affected by the new thoroughfare. They were designed by Sir Horace Jones. The open piers carry the Sutton arms, and the lamps on the piers are surmounted by Sutton's greyhound crests.” 2

The Charterhouse Square: http://www.british-history.ac.uk/survey-london/vol46/pp242-265 accessed 1

18/03/2016

Charterhouse square railing history: http://www.british-history.ac.uk/survey-london/vol46/pp242-265#fnn35 2

accessed 18/03/2016


http://www.british-history.ac.uk/survey-london/vol46/pp242-265

http://www.british-history.ac.uk/survey-london/vol46/pp242-265#fnn35

Description The railings surrounding the Charterhouse square have been constructed in standard pre-fabricated panels, bolted to intermediate stanchions which have rear stabilisers (back-stays). The railing run includes several ‘special sections’ such as curved and short panels.

Given the dates of manufacture these railings are likely to be made of mild steel, although an examination and suitable test should be carried out during any conservation works. A skilled practitioner should be able to identify the material from either a ‘nick-break’ or a spark test on a piece of material that is due to be replaced.

Figure1: The Charterhouse Square railing layout as inspected March 2016.


The railings enclose a green space and are breached by pedestrian gates mounted on cast iron columns. There should be four pedestrian gates in total. Two into the enclosure, at either end of a diagonal path, and two more pedestrian gateways to the charterhouse square road. At the time of inspection, the eastern pedestrian gate was missing from its mounts and the western gate was closed as part of building works. The gate locations are shown in figure 1.

Research into the railings has shown that these railings are based on the Bayliss, Jones and Bayliss ‘Nibal’ railing design, see figure 2. The pinched checks on the bars, which lock the uprights into the top rail are visible on the railing panels around the charterhouse square.

The finials on the charterhouse railings are of two designs, the majority being a traditional flat spear heads, with intermediate three pointed decorative heads. The finials appear to be forged from the same bar as the uprights, given the dates and scale of the Bayliss, Jones and Bayliss company, these finials are likely to be drop forged. See figure 3.

Figure 2: “Nibal" railing panels 3

Advert and company information: http://www.historywebsite.co.uk/Museum/OtherTrades/BCN/BJB.htm 3

accessed 18/03/2016


http://www.historywebsite.co.uk/Museum/OtherTrades/BCN/BJB.htm

Above figure 3: Railing finials and example of general condition. ‘Nibal’ cheek visible on left spear.

Below figure 4: Typical construction showing panel and bolted back stay.


Above figure 5: Typical railing panel dimensions and material sections.

Below figure 6: Back stay and intermediate stanchion details. Exact underground details were not part of this survey but likely to be similar to shown in figure 2.


From inspection is it evident that a length of railing is assembled by bolting and fixing together a set of standard components. The top rail will be a punched bar, with holes cold punched to allow the uprights to be passed through before being fixed to the bottom rail. A raised lump of metal can be felt under the bottom rail, indicating that the end of the railing uprights pass through the bottom rail and are either riveted or welded in place.

Each panel is held upright by a stanchion at either end, and each stanchion has a back stay bolted on. The panels are attached to the stanchions by means of a special shape connecting plate, which passes through a punched slot in the stanchion, and bolts two railing panels together.

Figure 7: Example bolted connection plate passing through stanchion.

The stanchion and backstay assembly are fixed into the ground to provide stability to the length of railings. In addition each railing panel has two ‘feet’ bolted to the bottom rail and fixed into the ground.

Typical dimensions and construction information is given in figures 5 & 6.

The pedestrian gates are manufactured to continue the aesthetic of the railings and continue the use of the same finials and material sections, although the construction demonstrates more traditional forging techniques. Generally the framework is tenoned and riveted together. The gate posts are cast iron and the gates make use of a bolted ‘component’ system for the hinges. The current lock cylinders are modern although make use of the original fittings. See figure 8.


Bolted connection plate

Stanchion

Top rail

Figure 8: Pedestrian gate layout.


Front StyleBack Style Bottom Rail

Top Rail Gate Post

Condition The Charterhouse square railings are generally in reasonable condition. The paint in places is in a poor state of repair and there are areas with moss and lichen growing on the ironwork. The majority of the ironwork is sound and has not yet suffered from material or detail loss due to heavy corrosion. Wastage caused by corrosion is mostly to be found at ground level to the fixing feet and stays. The railings generally require re-decoration.

Although this type of railing was designed to conform to the landscape, in several locations the Charterhouse square railings have moved out of vertical. Many of these instances can be attributed to root movement or impact damage to the panels. In a few places the stays and feet have corroded causing panels to wobble and move from upright.

The issues with the charterhouse railings can generally be categories in the following ways, please see the photographic record for examples of the issues given below.

Impact damage

The railings are constructed from relatively thin section material, this means that the railings are relatively easily deformed by impact.

There are four bays on the north and east sides that have suffered impact damage and has caused deformation to multiple bars, and in one case bent the rails. Given that this area is left to car parking these panels have likely suffered from vehicle collision.

Bent features

On inspection there appear to be no finials missing, however there are a few individual finials that have suffered deformation.

Several back stays have also been deformed, with some no longer attached into the ground. Other individual spears have suffered impact and a variety of bends and twists have been introduced around the railing length. This individual deformations are not as easily attributed to a specific cause.

Tree growth

In two places to the north of the railings, the trees have grown and engulfed the railings. Although this appears not to be harming the trees it has caused some movement in the railings. However in both cases the rails are completely engulfed and are no longer removable without damaging the tree.

Corrosion damage

Generally the railing design affords good airflow so that the ironwork will dry quickly and has limited places for pooling of water.

The majority of the corrosion appears to be effecting the ground fixings and the bolting plates through the stanchions. The ground fixings will be effected by the build up of organic material such as wet leaves and grass growing around the stanchions.


Improper welding

The original construction appears to use mechanical and traditional fixings only, any electric welding found on the gates and railings will be an attempted repair from a later date. One panel of railings, located in the south east corner by the wooden hut, has had the top rail replaced and all the finials have been welded in place. The top rail has been replaced with a thicker section of material, probably as a metric equivalent.

Throughout the entire length of the railings many joints, particularly to the stanchion fixing plates have been arc welded in an attempt to stiffen or repair the structure. The quality of this welding and finishing is poor and can detract from the original detail.

Panel movement and fixings

There is some movement and flexibility built into the design of the railings. However this is worsened by the poor condition of some fixings and bolting plates. Structurally there are few problems with the railings and maintenance including fixing replacement will improve the stability.

Railing Colour and Paint

The railings are currently painted in black and have not been galvanised. A visual inspection of the flaking paint suggests that these railing have always been painted black. As the railings were installed in the 1940s it is possible that early layers of paint may contain lead.

The paint condition varies around the railing length although the paint is failing and flaking in places throughout.


Conservation Proposal 1. In-Situ RepairsGenerally the railings should be left in situ with appropriate treatments undertaken as necessary. It is our recommendation that prior to any conservation works being undertaken, a trial panel be disassembled so that the ground fixings and components details can be copied and replacement components be manufactured to suit.

1.1. Fixings Generally

Any fixings that are to be replaced should be replaced with a suitable size and design in stainless steel. The original fixings appear to be either truss head screws or short coach bolts. If a direct replacement is not available a similar modern alternative such as a button head with lock nut can be used.

Where original fixings need removal but have seized or severely corroded, the fixing should be drilled or cut to avoid damaging the railing material.

1.2. Railing bolting plates

All railing bolting plates should be investigated and fixings tightened where required. Where damaged or suffering from excessive wastage (over 50% of thickness lost), new bolting plates should be used. These should be profiled or cut from a suitable thickness mild steel plate and galvanised. As per conservation guidelines, replacement components should be stamped with a date and makers mark to aid future identification of repairs.

Care should be taken during the removal of panels so that bolting plates are not cut or damaged.

1.3. Replacement ground fixings

1.3.1. Panel Feet

All ground fixings should be visually investigated and inspected for corrosion. Any feet that have significant wastage (over 50% of thickness lost) should be dug up and replaced.

The fixing feet should be replicated and reproduced in mild steel which can then be galvanised. As per conservation guidelines, replacement components should be stamped with a date and makers mark to aid future identification of repairs.

1.3.2. Back Stays

Where the back stay ground fixing has corroded or is missing, a replacement back stay can be manufactured from mild steel in a suitable section This should be galvanised and painted prior to re-installation in the ground.

As per conservation guidelines, replacement components should be stamped with a date and makers mark to aid future identification of repairs.

1.4. Bent features

1.4.1. Impact damaged panels

Damaged panels should be unbolted from the stanchions and feet. This will allow panels to be removed to a workshop and required components straightened to restore the panel. The panel should be tagged with a location to ensure it is re-installed in its original position.

1.4.2. Back stays

Individual bent back stays should be unbolted, or have fixings cut if required, to remove. Ground fixing should be dug up and inspected for required repairs or replacement. The item


should then be straightened and reinstalled in the correct position to ensure the panel is located plumb vertically.

1.4.3. Bent finials

Where not part of a damaged panel, bent finials should be spot heated and straightened.

1.5. Welding Generally

Electric welding is not an original fixing method for this type of railing and is therefore not suitable for restoration. Electric welding can be used to rebuild or repair original components in order to preserve as much of the original fabric as possible. Where undertaken, welding should be ground smooth and flush with original surfaces with no visible cracks or holes.

Where found on panels or fixings that are to de disassembled, electric welding should be ground off and original joints re-instated.

2. In-Situ DecorationIt is strongly recommended that the railings be re-decorated using a high quality exterior metalwork paint such as Dulux Metalshield. The use of two-pac epoxy paint is not suitable given the flexibility and movement in the railings. In our experience epoxy paint will crack at the joints and allow water to corrode the ironwork.

A paint analysis may need to be completed to confirm original paint colours and the presence of any lead paints.

2.1. Signs and boards

All signs, boards and abandoned bicycle locks affixed to the railings will need removing prior to the works. Signs and boards should be tagged and the location recorded before being carefully stored and re-affixed at the end of the project.

Any old cable ties or wire bindings to the railings should be removed prior to the works.

2.2. Preparation

The existing paint is in a poor state of repair and needs removal back to a sound surface. The railings should therefore be cleaned back using a high pressure steam cleaner to remove all loose and flaking paint. Thermatech system or similar using a water permeable matting on the ground to catch the paint flakes, Terram matting or similar.

A high pressure steam jet will remove failed paint, without breaking lead paint into dangerous dust and leaving any well adhering original paint coatings, without causing damage to the ironwork. The railings can then be hand sanded to smooth and feather the surface for painting.

Areas of corrosion should be descaled using chisels and wire brushes to work back to a sound surface. Corrosion should be treated with a rust converter such as Kurust or Jenolite prior to painting.

An polyester resin filler, suitable for use on ironwork, may be used to rebuild and smooth surfaces.

2.3. Undercoat

Once all repairs are complete, apply by hand to all metalwork a coat of exterior metalwork zinc phosphate primer. Pay particular attention to joints and fixings. Wherever possible components should be painted prior to re-assembly.


2.4. Top Coat

Apply by hand two coats of Dulux Metalshield exterior ironwork paint. Pay particular attention to joints and fixings. Wherever possible components should be painted prior to re-assembly. Any metalwork that is to be underground should be completely painted prior to re-installation, see point 2.4.

2.5. Redecorating Ground Fixings

All exposed ground fixings should be mechanically descaled to remove corrosion and where removed for re-use can be carefully abrasive grit blasted. The clean metal should then be coated with a high zinc content metal primer (Galvafroid or similar) prior to being completely repainted. All surfaces should be completely painted prior to reinstallation in the ground.

Any ground fixings remaining in the ground should be cleared back as far as is practicable and any corrosion mechanically removed with chisels and wire brushes. The corroded surface should be treated with corrosion converter such as Kurust or Jenolite before applying a high zinc content primer under the paint system as given above.

2.6. Tree Encroachment

Panels of railings that have been engulfed by tree growth should be left alone wherever possible. Preparation and decoration should be undertaken as far is practicable. The plan for protection of the trees is not part of this document.

3. ModificationMovement of the railing boundary will be possible and the original appearance can be maintained if the modification is undertaken sympathetically. Generally modification to the railing line will require tagging the railing panels before unbolting and removal for relocation. The stays, feet and stanchions will need to be dug up and inspected for reuse or repair.

3.1. Component Reuse

The component nature of the railings means that the existing railings can be completely salvaged and have new components manufactured only where necessary. If panels are to be removed from the square they can then be stripped and redecorated in a workshop environment which will give a high standard of finish.

3.2. Feet and stays

The feet and stays will need inspection and possible replacement as they will have suffered the most from corrosion. Accurate reproductions should be manufactured and can be galvanised before re-installation. Any old feet or stays that are suitable for replacement should not be galvanised (to identify as original) but can be carefully abrasive grit blasted to remove corrosion and then painted with a high zinc content metal primer prior to decoration with the paint system given above.

3.3. New Railings

Modern component systems rely on electric welding for fabrication of railing panels and may not offer exact matching to the existing railings. If extensions or more railing panels are required, moulds and details of the original should be taken and used to replicate the design. The cost of producing the tooling to replicate the original exactly may be prohibitive so electrically welded panels can be allowed. The original assembly methodology should be used.


Photographic Record

Image showing minor impact damage. The two uprights centrally have bent and the paint is missing in these areas.

Example panel showing individual bent finial and a bent back stay.


Example of paint condition. Note lichen and organic growth. Location: North side.

Typical railing condition. Some bends and deformation to railings can be straighten with spot heating. Generally railings are physically sound.


Eastern pedestrian gate. Note some corrosion staining on the paint.

Northern pedestrian gate.


Pedestrian gate fixings. The pedestrian gates are traditionally manufactured and jointed, as highlighted by the pin fixing used on the finials.

Pedestrian gate hinge fixing. Note corrosion staining. Washers have been used to compensate for wear, hinges should be checked and greased regularly.


Example of corrosion to stanchion base. In this instance the stanchion has actually separated from the body of the upright. Location: Right of phone box.

Example of electrically welded joint. The end of the rail has been poorly welded to the stanchion upright and the dome of the bolt has been welded to the rail.


Image showing tree root engulfing curved railing panel. Located North East side.

Image showing tree growth that has engulfed a special section of railing. Originally designed to avoid the tree trunk. Location: North East, right of pedestrian gate.


Documents

HC1168 Charterhouse Railings Report - Islington