HERITAGE EQ REPAIR & STRENGTHENING

The Old Stone House

The Old Stone House Cracroft, Christchurch was originally built in 1870 by John Cracroft.
It is currently listed as a Historic Place category 2 by Heritage NZ.

Due to the EQ events of 2010-2011 the stone and slate clad building was badly damaged and required extensive repair and strengthening work. This was part of the Christchurch City Council heritage building portfolio one of over forty structures.

On completion of the engineered design solution for the strengthening and approvals gained from CCC heritage division and the heritage architect, a careful part deconstruction of the building commenced. 

The main focus of the strengthening design was to install a steel diaphragm to the roof area which was tied back to the walls with steel sections at each corner fixed five metres vertically into the existing stone walls.

On removing the existing slate, it was found that the stone face of each gable was badly corroded with reinforcing rusting away. The original stone was deconstructed, new concrete and reinforcing installed then the stone cladding reinstalled to the same positions as the existing. Structural ply was then positioned over the roof and new tiles from Wales were installed to match the original colour and style.

Sacrificial steel beams have been used to support the two ends of the building being installed before rebuilding the two end ante rooms which collapsed during the EQ events. 

Further work was undertaken to the chimney and inside with the chimney breast and fireplace. The mezzanine floor and all window lintels had to be replaced with steel and concrete reconnections.

Contract value was just under $900,000 and the contract duration was twenty-four months.