by Tim Buxbaum, Architect

St John's Church, Woodbridge was built by public subscription in the1840s; its main feature was an unusual spire 42m (138 ft) high, made of stone ribs with brick infill, all carried on eight slender masonry piers. This remained an important local landmark both from land and river until the 1970s, when concerns about metal corrosion resulted in demolition. The remaining stumpy tower never looked right and an anonymous benefactor came forward a couple of years ago to fund a replacement.

It was not practical to replicate the original spire in masonry so it was agreed to design a lead-clad, engineered timber framed spire, carried on a steel octagon base tensioned in situ with Macalloy rods.

This approach was possible because of an existing compression ring at the apex of brick vaulting. It made sense to construct the spire on the ground beside the church, including a hand forged stainless steel cross finial, then lift it bodily into position using a 225 tonne crane which could just get down Woodbridge's narrow streets. Once in position the steel octagon base was clad with gunmetal castings and slate louvers, which can be withdrawn into the octagon to assist maintenance.

The project; was notable for successful teamwork, particularly on the day of the lift when a variety of disciplines had to work closely together against the clock. A range of technology was used during the project to solve several unusual problems; one of the trickiest being how to remove the upper lifting frame without mobilising a second crane - the solution was a reassuringly simple device made up from threaded rod and wheelbarrow wheels!

Structural Engineer - Whitby Bird;
Quantity Surveyor Castons;
Main Contractor - Elliston Steady & Hawes;
Steelwork Subcontractor - Suffolk Welding Co;
Leadwork - Anglia lead.

This article was published in "Architecture East of England" Summer 2003