Fire performance, chemical composition and resistance to pull-out loads were all factors considered by one of the leading national contractors in the selection of Magply MgO boards for the cladding build-up on four apartment blocks in Bristol.
The development in the historic dock city’s Redcliff Quarter conservation area is being led by Galliford Try for developer, Redcliff Quarter MLP with the designs of Lyons+Sleeman+Hoare Architects combining new build structures and elevations with retained Victorian brick façades.
The initial description of the building was for phase 1 (114 apartments + 14 duplex). Redcliff Quarter Phase 2 is the construction of 118 apartments which is a mix of 1 and 2 bedroom apartments with 4no retail units along cross street. The facades are a mix of Recon Stone Panels, Brickwork, composite cladding and El-zinc Cladding.
The cladding contractor is responsible for installing all of the El-zinc cladding on the project, utilising VM Zinc clips to attach the very distinctive and lightweight material over a sub-structure of steel framing, the 12mm thick Magply boards and a breather membrane.
Due to the El-zinc material only being 1mm thick added support was required to prevent the cappings from bending out of shape. Traditionally this would be ply, however due to the requirement for all materials to be A2 fire rated in buildings over 18mm ply was not a suitable product. Magply was used in its place due to its property’s.
The Externals Manager for Galliford Try, Martin Sykes, commented: “The main area of use for the Magply boards on this project is within the build-up for the ‘picture frame’ type feature around the main entrance, where we have secondary steelwork and Metsec frame to build out from the main structure. However, because the chosen cladding material is VM Zinc you have to be very careful about the chemical composition of what it is in contact with, to avoid degradation.
We considered a number of different board types to meet the required fire-rating, but Magply’s PH level proved to be more compatible with the zinc, while the manufacturer was also able to supply satisfactory data on pull-out tests, to ensure the stability for the cladding brackets. The boards, covered by the breather membrane, are also being used beneath all the cappings on the building, mounted between the galvanised supports, enabling the contractor to complete all their installation work.”
Backed by BDA Agrement certification, Magply MgO boards present a fire-safe and environmentally friendly alternative to conventional plywood or OSB products. Additionally, the unique production process keeps the chloride content to just 0.01%, enhancing both stability and long-term durability. The different thicknesses of panel are also widely used as a substrate board for the direct application of proprietary render systems, as well as for flooring and flat or pitched roof build-ups.