St Marylebone Church
Internal Birdcage | Scaffolding | Temorary Roof
Tube & Fitting, Layher
SRM Special Projects
This is a flagship heritage restoration project of the grade I-listed St Marylebone Parish Church in central London. The project will see the 1817 church, which gave the surrounding Marylebone district its name, taken off Historic England’s Buildings at Risk register
The church will remain open to worshippers throughout the works, during which the roof will be replaced, lost architectural features reinstated and new internal walls and floors installed. A lift will also be installed to provide better access into the building’s two-century old crypt, which will house new visitor and community spaces. The work will be completed by a team of specialists led by Sir Robert McAlpine Special Projects.
WHAT PHD SUPPLIED
With a proven track-record of successfully working on heritage projects, PHD were chosen as the specialist scaffolding and access provider for this prestigious project. For the outside of the church PHD provided full external tube and fitting access for the masonry work which included stone cleaning and stone repair, decorating, and replacing leadwork. The entire building was covered by a Dessa temporary roof system so the whole roof could be replaced with Welsh slate.
The temporary roof was erected by hand as there was no access for a crane. To do this, platforms were built either side of the church tower and the roof was built section by section. The roof consisted of 17m x 2.5m bays and a 28m dual pitch span. All 17 bays were rolled into position on the track system. The temporary roof was also constructed with a full gutter system for water management. PHD also provided the hoist and hoist runoff.
For the internal work PHD designed and erected a birdcage scaffold for access to the plastered ceiling inside the church. This presented many challenges due to the limited ground loadings and every care had to be taken not to cause any damage to the historic finishes. After several design meetings a solution was agreed. The scaffold birdcage was bolted to the internal walls of the church and spanned 18m with no support from the ground at all.
Six sets of Dessa beams were bolted to the walls of the church using 96 x 125mm stainless steel resin anchors. We used 780mm beams to span the box beams and once laced and braced together transoms and boards were added to form the finished deck. The total weight of the scaffold bolted to the walls was 54 tonnes.
The Church is Grade I listed and is historically and architecturally significant therefore the utmost care had to be taken to install suitable access to facilitate the work while also being sympathetic to the building fabric. Scaffold ties were originally not permitted due to this constraint, which was unrealistic. Through design development the quantity of ties into the existing structure are the absolute maximum permitted by both the Church Diocese and local authority (Westminster).
Ground loadings were limited due to the voids and vaults below ground and the historic building foundations. The site is compact and falls within Westminster’s conservation area and therefore does not allow for an excessive footprint. The church had to remain open to the parish throughout the project, not only for church services but it also houses an NHS walk-in centre. This was all considered throughout the design process and also throughout the construction phase. The internal Nave scaffold was also designed to minimise the visual impact on the Church during services.