David John MCIOB
With this high-profile project hit by a once-in-a-millennium flood and the threat of a 6m-high retaining wall collapsing, David John brought the technical insight and site experience that managed out the risk. He identified the buildability and budget issues of the proposed precast concrete cladding, and switched to a time and money-saving combination of steel frame and traditional brickwork. His quality focus won the architect’s praise and exceeded the client’s expectations.
About the Project
Llys Cadwyn, Pontypridd
Construction of two five-storey office blocks and a library-cum-gym, completed in 134 weeks.
Client: Rhondda Cynon Taf County Council
Contract: JCT, design and build
Risk management is the construction manager’s stock in trade, as David John’s project makes very clear. Not only did an adjacent river overflow the site’s boundary in a once-in-a-millennium flood, but a 1960s-built 6m-high retaining wall for the adjacent highway started shifting early in the construction of the scheme’s three buildings. Positive and determined, Dave exploited his technical understanding and a wide-ranging experience that dates back to accompanying his stonemason father to work during school holidays.
To help protect the project from further flooding, David ran a brainstorm workshop to generate a list of extra works. He overcame the absence of records or drawings indicating how the wall had originally been constructed by locating historic photos of it under construction that indicated there was sheet piling behind the wall. He then developed and installed a whaler propping system that anchored the wall.
David identified the buildability and budget issues of the proposed cladding for the office blocks – precast concrete panels faced with brick slips. With a huge crane required to lift such heavy panels and oversized concrete frames and foundations needed to support them, he changed to a time and money-saving combination of steel frame and traditional brickwork. To mitigate risk, the Danish bricks (longer, wider and shallower than the UK standard) were ordered a year early, stored off site and brought in when required.
By building a significant sample panel of the envelope at considerable project cost, he eliminated the air leakage risks of the pebble-shaped library-cum-gym building, particularly around the leaning diamond-shaped windows It allowed the site team to fully understand the detailing issues and practise the installation of roofing and breather membranes, windows and flashings.
He delivered on time, within budget and to a standard that won the architect’s praise and exceeded the client’s expectations.