Historic buildings hold cultural significance to a city and are typically tourist attractions which are loved by people at home and abroad. Almost all of these historic buildings have required restoration in the past simply because of their age and the need to conserve them. While restoring historic buildings is similar to restoring any structure, greater care must be taken to ensure that scaffolding and other supporting structures don’t damage the historic fabric.
When damage is incurred on non-historic buildings that are caused by incorrectly erected scaffolding, it can often be repaired despite being an unnecessary expense. On the other hand, when historic fabric is damaged by scaffolding it is typically permanent and significant detail may be lost. Experience shows that the majority of damage caused when restoring historic buildings result from minor errors or a lack of attention to detail. This article will highlight the importance of the designer’s role and the erectors of scaffolding in ensuring that all historic fabric remains undamaged when undertaking restoration work.
The design of the scaffolding used to restore historic buildings should not be undertaken by the scaffold erector. A qualified engineer should complete the scaffold design in conjunction with the architect as they have been typically working with the building for many years and are aware of its flaws and weaknesses. It’s vital that the scaffold designs are completed before any scaffolding is erected and the level of planning should be proportionate to the scale of the job.
Sufficient planning should be undertaken so that the erector of scaffolding knows exactly where the foundations will be positioned, and where boarded out decks can and cannot be placed to minimise any potential damages. Whether the drawings are pencil or computerised, the main objective is to consider the weaknesses of the structure and where potential damage is most likely to happen. The engineer or architect should always review the contractor’s plans for scaffolding irrespective of the size of the project.
‘Independent tied’ scaffolds are commonly used in historic building restorationsto offer support for painting, pointing, or other maintenance work. They are named ‘independent’ simply because they require no vertical support from the structure, and ‘tied’ given that they derive horizontal stability from being tied to the structure. Tying any scaffolding to the surface of historic buildings can clearly cause problems as the building may be feeble and not capable of providing scaffolding support. Consequently, support is often achieved by using external scaffold buttresses or by tying scaffold to a temporary internal birdcage scaffold.
Here are some of the most common scaffoldproblems encountered when restoring historic buildings:
- Scaffolding to building interfaces – Scaffolding always has a tendency to move slightly, such as a tube end rubbing on a wall face, which can potentially damage the historic fabric and cause permanent scarring. Therefore, all points of scaffolding which can potentially rub against the building’s surface must be protected by plastic end caps for example.
- Fixings to masonry – Where any fixings are planned to be made to brickwork or stone, the masonry must be examined beforehand to ensure it is adequate. If not, the fixing could potentially displace a brick or stone and not only damage the historic fabric, but also endanger the safety of the scaffolding. Any fixing made to the surface of an historic building should be stainless steel.
- Temporary roofs and buildings – Temporary roofs and buildings are typically light structures which require lateral stability and resistance to wind uplift. It’s highly recommended to employ a structural engineer to assist with the erection of these structures and to review the planning of the scaffold erector.
- Workforce – It’s highly advised to educate the workforce of the value of the historic fabric by giving them a tour of the building. Those workers who understand the value of an historic structure generally take more care and have greater attention to detail when completing their tasks.
Attention to detail and a great deal of planning must be undertaken when restoring historic structures. There is always the risk of scarring the surface of these historic buildings with scaffolding and other temporary supports, so architects and engineers must be involved at all levels of planning. It’s paramount that the architects and engineers have a clear understanding of the scaffolding requirements (and consequences of errors) to ensure the job is completely successfully.
If you have any further questions regarding the use of scaffolding on historic building restorations, get in touch with the experts at Uni-Span by phoning 1300 882 825.