St. Paul’s Cathedral, London – Equal Access Ramps

St. Paul’s Cathedral, London – Equal Access Ramps

Daytime picture of equal access ramps at St Paul's Cathedral

Historic St. Paul’s Cathedral was designed by Christopher Wren. The new Equal Access Ramps were designed by CAROE Architecture. The ramps are the most significant external change and addition to the Cathedral in its 300-year history. The Equal Access Ramps are a permanent reversible structure, ‘floating’ over the original entrance steps so as not to damage the original historic fabric of St Paul’s Cathedral.

Harrison Goldman assisted CAROE, with quarry visits, sourcing, and selecting the Jordans Whitbed limestone blocks from Albion PLC, Portland Dorset. We continued to assist on site in London, with checks to ensure the quality of the stones used for the walls of the ramps. Chinese granite was used for the ramp surfaces. 

Night-time picture of equal access ramps at St Paul's Cathedral

Jordans Whitbed limestone was selected because it matches the original white Portland limestone and has shown itself to be durable in the London environment. For this project, it was important to select a bed that is most suitable for use at pavement level and has the characteristics that allow a tooled finish and desired appearance to be achieved. 

Client: Corporation of the Cathedral Church of St. Paul’s London 

Architect: CAROE Architecture 

Stone Consultant: Harrison Goldman 

Wong Avery Music Gallery, Trinity Hall, Cambridge

Wong Avery Music Gallery, Trinity Hall, Cambridge

Wong Avery Music Gallery

Award winning, Wong Avery Music Gallery, is a music practice and performance space for Trinity Hall, Cambridge. The stone-built music space sits in the centre of Avery Court, on the College’s central Cambridge site, adjacent to several listed buildings including the chapels of both Trinity Hall and Clare College. Harrison Goldman faced the technical challenges of this stone load bearing construction, made of thin stone columns, allowing the entrance of natural light.

Wong Avery Music Gallery

GROUND FLOOR – technical description.
Ground floor internal finishes include regularly spaced 405mmx75mm load bearing stone columns arranged perpendicularly to a Greek-Cross shaped performance and audience space. The stone columns are cut into, and structurally bonded with, the blockwork walls, and provide substantial lateral stiffness. The ground floor columns are the core of the structure, bearing the load of the upper concrete slab and glazed lantern. Harrison Goldman designed a unique and flexible fixing system where the stone columns also acted as anchor points for a metal channel system contained within the 80mm insulated cavity, which restrains both the external 40mm thick stone cladding and other services including drainage. The insulation, the waterproofing breathing membrane and installations such as the rain water pipes, were installed between the internal stone columns and the external stone cladding.
For this reason, the relationship between the internal stone columns and the external stone cladding and the metal ties that connect the stone columns with the external cladding, were exhaustively studied, to avoid surface condensation inside the building.

Wong Avery Music Gallery

LANTERN – technical description.
A glazed lantern in the central bay of the Greek Cross is different. The lantern was designed to bringing natural light into the centre of the plan, where performances and recitals take place. Visually, the cubic lantern distributes a continuous sequence of thin stone columns with glazed windows in each column bay, this gives the impression that the thin lantern columns are load bearing, but you will be astonished to realize the lantern columns rest …on air!

Finding an appropriate technical solution to bear the load of the internal lantern stones was a real challenge. Harrison Goldman proposed and designed a complex load bearing solution, which was able to accommodate both vertical and horizontal lantern stones, (thus the look of floating on air) but the design continues to be challenging because the bottom surface of each column is visible, which meant Harrison Goldman could not load the stone from the base, so we designed a clever loading system, where each stone column rests on a T shape profile. The T shape profiles are accommodating and are resin filled inside a notch in the back face of the bottom stone of each column. Being this face the only non-visible face of the stone.

Wong Avery Music Gallery

CEILING – technical description.
The interconnected ceiling lattice is cut to very tight tolerances. Each part of the stone lattice is suspended on two bolts hanging from the prefabricated matching steelwork forming the roof above, passing through the depth of stone, and mechanically anchored towards the exposed lower face. Another interesting point which required a detailed study and complex solution was the thin stone fins, dropping perpendicular from the ceiling.

Wong Avery Music Gallery

SUSTAINABLE STONE CONSTRUCTION

Stones form the maximum protagonist of the construction material for this building. The acoustic performance of the internal stone, is very important for a building dedicated to music. Three different types of limestone were examined in a reverberation chamber test. The Jordan’s Basebed limestone was chosen for the interior columns, after having the best results, due to a more homogeneous finish. The external primary frame and lantern columns, used the same limestone, to match with the internal columns. The external cladding is Grove Whitbed limestone, chosen for its unusual character of significant shell inclusions and voids, this gives the stone an interesting textural appearance.

The external plinths are granite stones, as they are considerably less porous to water than limestone. The Delank Granite chosen, has a warmish tone which compliments both types of Portland limestones used. The other limestone is Haysome Spangle Purbeck, used exclusively for flooring. Two limestones; Albion Jordans Basebed and Grove Whitbed were quarried in Portland, Dorset. The other limestone, Haysome Spangle Purbeck, Dorset. The granite was quarried in Cornwall.

Stones used in the project were all quarried in England, illustrating some important points: the stones perform perfectly in the UK climate; transportation of the stones to Cambridge was minimal; this combination considerably reduced the carbon footprint for this building. The quarries also operate to a high ethical standard with Health & Safety, pay, working and environmental conditions all at the forefront. This gives the client a guarantee of excellent working practices, with a low carbon product of the highest quality and standard. Everyone can be confident of its ethical and sustainable credentials. This new, modern stone building, is a solid investment for future generations of students and performers at Trinity Hall College.

Project Team
Harrison Goldman, Stone Consultant & Design Engineer, partnered with Brown & Ralph, Stonemasonry Contractor. Barnes Construction and Niall McLaughlin Architects.

To quote Sir David Attenborough: ‘It is possible to achieve much more working with others than any
of us can achieve alone’.

80 New Bond Street

80 New Bond Street

Harrison Goldman were appointed as Stone Consultant, to work with ORMS Architects. We proposed Broughton Moore Green Slate from Burlington Stone. This stone was adopted for use externally and internally on this project. This outstanding material is suited perfectly to the British climate, and is sustainable, therefore has a low carbon footprint.

Bond Street Arch completed
Bond Street Window Cladding

For the external slate, Harrison Goldman reviewed the project specification relating to the natural external stone requirements; by reviewing the relevant external stone details. Basic guidance coordination with GIG and checking suitable thickness of proposed external stone types based on stone module size and DoP (declaration of performance) technical data. We advise on compliance with relevant British and European standards and produce a quality control specification for the external stone, which included; Stone Type classification, Stone selection & sample range, controlling British and European Standards, testing-Factory Production Control (FPC) & Project Specific Testing Manufacturing & production tolerances CE certificate & DoP requirements. Fixings, Cleaning and maintenance.

Bond Street Internal Arch
Bond Street Desk

For the internal slate, Harrison Goldman reviewed the project specification relating to the natural internal stone requirements and reviewed the relevant internal stone details. We checked the suitable thickness of proposed internal stone based on stone module size and DoP (declaration of performance) technical data base details and advised on compliance with relevant British and European standards. We produced a quality control specification for the internal stone, which included; Stone Types Stone selection & sample range, Controlling British and European Standards, Testing-Factory Production control (FPC) & Project Specific Testing Manufacturing & production tolerances CE certificate & DoP requirements, Movement Joints, Slip and abrasion (health & safety) Protection, Cleaning and maintenance.

Four Courts, Dublin Ireland

Four Courts, Dublin Ireland

four-courts-dublin-ireland-hg

Since 1921 the Four Courts, Inns Quay, Dublin has suffered continuing failure, and in February 2016 Harrison Goldman was appointed to assist the Office of Public Works in carrying out investigations into the condition of the capitols and cornices to the peristyle.

Designed by Thomas Cooley, work on the Four Courts building commenced in 1776. Following Cooley’s death, the architect James Gandon was appointed and the building as we see it today was completed in 1796.

During the Civil War 300-400 men of the anti-treaty Republican Force, led by Rory O’Connor, occupied Four Courts on the 15th April 1922.

On 29th June 1922 Michael Collins advised the provisional government to attack the building to end the siege by dislodging the rebels. The attack was carried out using artillery borrowed from the British.

Despite the shelling of the building, which was completely gutted, the structure of the building was still standing. However the timber domed copper covered roof was destroyed, leaving the round hall beneath completely ruined, together with the Portland stone columns to the peristyle, which were shattered by the shelling and damaged by the heat.

The 24 Corinthian capitols seated on top of the columns and supporting the peristyle, also suffered damage from the shelling and heat.

Although the Portland stone columns were replaced the damage to the Corinthian capitols only affected the exposed carved faces. During 1925-26 new Portland stone columns were erected and the Corinthian capitols were rotated 180° exposing the undamaged face. Two capitols had been completely destroyed and were replaced using cast stone.

Repairs carried out during the 1920s were starting to deteriorate with problems being reported and repairs carried out to the entablature and capitols in 1942.

Problems continued with the stonework through the 1940s, 50s and 60s and some repairs were carried out, however in 2011 a section of one of the column capitol fell on to the roof of the Four Courts below. The Office of Public Works appointed Trinity College School of Engineering to undertake analysis and testing of the stone.

four-courts-dublin-ireland

Harrison Goldman’s investigation considered in detail the work carried out by the Engineering Department of Trinity College. This work involved close inspections of all the existing stonework and the preparation of a detailed reports and annotated drawings, identifying the capitols that needed replacing, with proposals for the remedial work to the Portland stone cornice to the peristyle and the granite parapet. The worst damaged capitols identified were replaced.

cornice-before
Before
cornice-after
After

Produced by:
Harrison Goldman ©
December 2021