Building study: Levitt Bernstein’s Bristol Beacon

Bristol Beacon, the music venue formerly known as Colston Hall, reopened at the end of last year after the third major refurbishment in its long and illustrious history. Originally opening in 1867, the South-west’s largest music venue is perhaps best known for the roll-call of stars who played there during the 1960s and 70s, including Buddy Holly, Ella Fitzgerald, the Beatles, the Rolling Stones, Jimi Hendrix, the Who, David Bowie and Elton John.

With this latest refurbishment, owner Bristol City Council and the building operator, the Bristol Music Trust, are again hoping to attract the biggest stars to Bristol. The last refurbishment took place in 1945, during a time of postwar austerity, and over 70 years later was no longer fit for purpose. The main auditorium was set out in cinema style with a huge first-floor balcony that badly affected the acoustics, the sightlines were poor, the inadequate ventilation system was noisy and the narrow, armless seats were a major source of complaints.

In 2001, aware of the venue’s serious shortcomings, the council commissioned Levitt Bernstein to carry out a feasibility study to assess options for the building’s future. The architect came up with six options which ranged from leaving the venue as it was, building anew or transforming the building into a world-class concert hall with the capacity to support commercial revenue. In a decision that has come back to haunt it, the council went for the full monty.

“The aspiration was to make this an international-standard concert hall that can compete with other venues in the UK and internationally and make it a destination for major orchestras, for example,” explains Thomas Böhringer, Levitt Bernstein’s senior architect. “And, at the same time, make it accessible to everyone with multifunctional spaces suitable for everything from orchestral to rock, pop, jazz and the spoken word.”

The work has been done in two phases, with the first phase completing in 2009. This involved the redevelopment of a former gas showroom next to the venue into a new foyer building with generous circulation space, bars and restaurants, a booking office and step-free access to the halls in the existing building once these were refurbished in the second phase.

The new-build first phase was uneventful, but the second phase has been anything but. Work started in 2019 with the budget set at £48.8m and completion in 2020. This proved to be wildly optimistic as, by March 2021, the building was not finished and costs had risen to £107m.

This was not the end of it as costs had risen to £132m by January 2023, with completion then expected by November 2023. Why has this job ended up costing nearly three times the original budget and has this investment been worthwhile?

Phase two included the complete refurbishment of the main auditorium to turn it into that world-class music venue, turning a smaller hall from a bar back into a performance space and refurbishing the atrium between the two performance spaces. The colonnaded entrance lobby at the base of the atrium has been turned into a restaurant as people now enter via the new lobby building.

The cellars under the main hall were originally built as a bonded warehouse thanks to the building’s proximity to the docks and have been turned into a new performance space along with music rooms for students and a recording studio. There are new dressing rooms, a green room and the building is now fully accessible with a new ventilation system.

The main reason for the cost overruns is the fact that the building turned out to be in much worse condition than anyone envisaged. In 2022 the external auditor Grant Thornton said there had been limited exploration to understand the condition of the building before work started because the building was in everyday use and the council had underestimated the complexity and difficulty of the work. The work has been done by Willmott Dixon on an NEC contract with the council bearing the risk for any unexpected issues.

The problems stem from the fact that the building was poorly built to start with, which was not helped by two major fires in 1898 and 1945 followed in each case by major rebuilding work. The 1945 refurbishment took place during postwar austerity with the result this was done on the cheap.

“The roof was very much a farmyard-type structure with miniscule trusses and clad with asbestos cement sheets,” explains Jason Hunt, Willmott Dixon’s senior operations manager. “The first big construction challenge was to clear 12 tonnes of asbestos out of the roof.”

The auditorium interior was removed, leaving the four outside walls and temporary works to support these now the lateral restraint offered by the roof structure had gone. The vaults under the auditorium made inserting a new, independent steel structure very difficult, so the plan was to take the vertical loads through the existing masonry walls.

These turned out to be very fragile. “Over the first 18 months, we were peeling layers of the onion away and realiszing that things were not as assumed and most of that was more of a challenge than we had anticipated,” Hunt says.

For example, the team discovered a large gable at one end of the auditorium that was much wider than the wall below. The overhanging element was unsupported, so was at risk of collapse – a scenario that played out. “We came in one morning and there had been a catastrophic collapse of a couple of tonnes of masonry overnight,” Hunt says.

Another problem was the discovery of three ancient wells. Hunt says two of these “couldn’t have been in more awkward positions” as one was directly under the front of the stage and full of rubbish. “It was in the most inaccessible place, with headroom of about two metres,” Hunt says.

“We tried all sorts of modern vacuum excavation techniques, but we couldn’t get the stuff out.” In the end the team managed to excavate down three metres, enough to insert a concrete cap and make it safe. The other wells were under a lift pit and under the get-in yard, the area where props and equipment are brought in and out of the building.

The old entrance area, which is now a restaurant, features a grid of brick columns supporting the floor of the Lantern Hall, the smaller of the two auditoriums. The plan was to replace this floor with concrete to acoustically isolate the restaurant from the performance space above.

What appeared to be substantial brick columns in good condition turned out to be hollow as these had been used as ventilation ducts. Just half a brick wide, these were not up to the job of supporting the weight of the concrete floor.

The columns were full of rubbish, which had to be removed so that these could be filled with concrete. This was a delicate operation because the fragility of the brickwork meant the columns had to be strapped and filled one metre at a time to stop these bursting from the pressure of the wet concrete mix.

Much time was spent inserting the new steelwork for the roof and other elements into the walls. The plan had been to insert padstones into the walls to spread the loads from the steel beams into the masonry.

Installing the padstones was challenging because of the unstable nature of the masonry, so these did not necessarily match up with the original design intent. The steelwork had to be made up from site surveys as the length of individual elements depended on the exact location of the wall and where the team could insert the padstones.

“Every piece of steel on the job was based on a survey rather than the design and ended up longer or shorter depending on the final position of the padstone and location of the wall,” Hunt says, adding that it would have been easier to demolish the building and start again – an option precluded by the grade II listing.

Two, four-storey high chimney breast-type structures on either side of the main stage required some complex structural gymnastics. With an opening at the front to create seating space, the plan was to make the openings wider to fit in more seats. This involved cutting a section out of the masonry piers on either side of the opening to widen it while supporting the concrete beam at the top of the opening as the areas of support at the ends of the beam were being cut away.

Three I beams were laid side by side under the concrete beam to take the weight of the wall above. This was supported by new steel columns on either side of the opening. The columns also supported the ends of the first-floor balconies on either side.

Large, L-shaped steel plates have been used to stabilise the new structure by tying it back to the main wall. “The issues we had with the stability of those columns probably cost the job six months at that end of the hall,” Hunt says.

With the difficult structural work out of the way, work could begin on putting in the new interior which uses a mix of materials. “One of the main acoustic drivers is creating textures and materials throughout the auditorium that allow you to scatter high-frequency sounds, but also at the same time, certain areas need to be solid and sturdy enough to reflect the deep bass frequencies,” Böhringer explains.

Brickwork is an ideal material because it reflects rather than absorbs bass frequencies, but the state of the walls meant a new inner wall had to be built above first-floor balcony level – complete with decorative arches to reference the original high-level windows. “The brickwork was too ropey to leave as a final finish,” Böhringer says.

“The arches have been replicated in a solid skin of new brickwork two storeys high. That comes with its challenges, because the new brickwork needs to be tied back to the base of existing masonry.”

Sliding stainless steel rails were used to tie the new wall back to the original to minimse the amount of fixings. Böhringer says the bricklayers relished the challenge of this job.

“I thought it would be one of the most difficult packages, but it was actually one of the easiest,” he says. “The masons were exceptionally skilled, loved the challenge and did a really good job. The same gang did both sides which made a huge difference in terms of keeping the work consistent and ensuring the quality was the same on both sides.”

The new auditorium, called Beacon Hall, features large areas of wood. Drapes can raised and lowered, including over the new brickwork to enable the acoustics to be tuned to different types of performance. This is supplemented by inflatable baffles in the ceiling.

The large rear balcony has been replaced by two smaller balcony tiers which extend around the side of the auditorium to the stage. The seats are wider and feature arms. This means seating capacity is slightly reduced to 1,866 despite the extra balcony tier and space in the alcoves on either side of the stage.

The stage features two 14m-long sections at the front. Each is 2m deep enabling the stage to be extended forwards by 2m or 4m. These drop down into a large space in front of the space when not needed.

The seats are fixed to wagons which can be rolled forwards to this area and dropped into the basement to create a large open, standing space for 2,124 people. Half the seats on the rear balcony can be moved out the way too.

The baffles in front of the balconies reference Bristol’s maritime past as these are suggestive of sails while the steel structure at the sides of the auditorium supporting the balconies and technical rigging floor are suggestive of ships’ masts. One original feature from the 1950s refurbishment remains – a three-storey high, 5,372-pipe concert organ at the back of the stage was dismantled and taken back to the original manufacturer, Harrison and Harrison’s works in Durham, to be refurbished.

Heating, cooling and ventilation is taken care of with a new, six-storey high steel-framed plant tower behind the stage in the get-in area. Accoustically separated from the auditorium, this includes air handling units at roof level which feed air via 2m section ducts into two risers at the back of the auditorium. Air is fed into the auditorium via a plenum under the seats.

Unfortunately, there was not enough space for air-source heat pumps, so the building is heated with gas boilers and cooled by chillers. The roof is covered with PV panels to offset some of the carbon emissions, which are 54% better than before the refurbishment.

Outside Beacon Hall, the atrium was a more delicate job as most of this has been retained and conserved. The upper floor was removed and recreated as a balcony providing access to both auditoriums. The balcony is one metre higher than previously to create space for a mezzanine floor below which can be used as additional performance or private function space.

Removing the floor was a delicate task as the cast-iron columns supporting the upper floor and the stone columns above had to be stabilised. A pair of stairs dating from the 1900s were removed because these were at odds with the symmetry of the space. A single stair replaces these and goes back to the original, more symmetrical Victorian layout.

Some delicate conservation work was required to the atrium roof topping this space, and the ceilings. The plan was to reglaze the roof lantern and repaint the frames but the lower part was too rotten.

“We weren’t going to touch any of this, but it literally fell apart in our hands,” Hunt says. The lime plaster panels below the rooflight had to be replaced too.

The oak joists supporting the ceiling were also rotten in places, a job made more complex by the conservation officer’s insistence that new timber was scarfed into the rotten areas rather than replacing all the beams. “What was going to be six to eight weeks’ work became six to eight months,” says Hunt. The Lantern Hall has been conserved and restored with new double-glazed windows and will be used for smaller events – it has capacity for 500 standing or 296 seated.

The old entrance area below the Lantern Hall has been transformed into an attractive new restaurant. Extra space has been gained internally by pushing the glazing out to colonnade at the pavement edge. The old vaults under the auditorium have been transformed into a third performance space called the Weston Stage.

This can seat up to 120 people or 200 standing and is an intimate, atmospheric space complete with a bar; it will be ideal for club and jazz nights and can be used for conferences too. This area also includes music practice rooms, a recording studio, dressing rooms and a separate artists’ entrance.

Part of the building’s reinvention was to drop the name Colston Hall. Edward Colston was a 17th-century Bristol-based slave trader and, given the toxic connotations and the fact he had virtually no connection to the building as it was completed nearly 150 years after his death, the name has been changed. Plans to change the name were underway before the toppling of Colston’s statue in June 2020.

The name Beacon Hall is rather bland but the venue is impressive with an appealing blend of modern and Victorian style, large and small performance spaces and lots of circulation space, food outlets and space for more commercially focused activities such as conferences.

Beacon Hall is unrecognisable compared with the previous iteration. It is spacious, looks good and the sophisticated acoustics should mean there are no barriers to any type of musical performance. Whether it will once again attract the biggest names in music and prove to be worth the investment for the people of Bristol remains to be seen.