For the first time since its construction in 1867, the Royal Albert Hall's landmark exterior is being radically altered. Using traditional Victorian construction methods, craftsmen from PAYE Stonework and Restoration are building a high arched entrance to house a new ticket office.

This new, fourth entrance to the oval-shaped concert hall was designed to match exactly the existing porches in both materials and construction techniques.

Resurrecting skills last seen during the building of the vast railway arches of the 1800s, expert carpenters were recruited to construct a precise wooden framework for the new main arch. The three-storey fabrication was prepared off site in sections and was swung into position, over the Hall itself, using a 40-metre mobile crane. This wooden former supported the arch as it was painstakingly constructed in terracotta and brick.

The new porch's decorative facade is a replica of the Victorian designs using modern terracotta sections cast from new moulds. Six months before any building work started, specialists were called in to map the building's ornate external embellishments. Latex rubber castings were made of all the building's decorative features, and these were used to form moulds to manufacture exact copies of the 19th Century terracotta.

During construction, the hollow terracotta sections were positioned and bonded into the building whilst being supported on the heavy-duty wooden framework. As each course was put in place, the centre voids were packed with a brick and mortar-based fill, replicating Victorian techniques.

This process was repeated until the arch was completed and locked together to become self-supporting.

Unlike modern buildings, the Royal Albert Hall's walls are a structural combination of brickwork and terracotta mouldings, rather than decorative external cladding over a load-bearing cavity construction.

This meant that PAYE's craftsmen had to build multiple layers of brickwork, in some places extending to over a metre of solid construction. The bricks themselves were especially made to Victorian Imperial measurements, so as to reproduce in both size and colour those used in the mid-19th century.

As in much of PAYE's work, laboratory tests were used to analyse the mortars in the original building. This allowed the company to produce new lime mortar mixes that no only matched the Victorian colour and texture, but also produced the same flexibility as the original.