Tower and spire stonework:

Craiglockhart Parish Church

Edinburgh · 2016

Our role: Principal contractor and specialist stonemason
Client: The General Trustees, Craiglockhart Parish Church
Architect: Hypostyle Architects
Structural engineer: Will Rudd Davidson
Value: Under £0.5m
Programme: October 2015 to May 2016
Scope: New sandstone replacements and indents, lime repointing, Paraloid crack injection, micro-pinning, pigmented lime mortar repairs, pinning and stitching of pinnacles and tracery, parapet downtake and rebuild, grouting of voids, new carved stone

Craiglockhart Parish Church was built in 1889 to designs by George Henderson, with its tower completed in 1908. It is built in Locharbriggs red sandstone in the Scots Gothic style, with rubble walling, ashlar dressings, corbelled diagonal buttresses, carved pinnacles and a short spire. Working for the General Trustees under Hypostyle Architects, we carried out the external stone repairs to the tower and spire, from the plinth to the finial, over the winter of 2015 to 2016.

Craiglockhart Parish Church, Craiglockhart Drive North, Edinburgh — photograph 1

Craiglockhart Parish Church, Craiglockhart Drive North, Edinburgh — photograph 2

Craiglockhart Parish Church, Craiglockhart Drive North, Edinburgh — photograph 3

Craiglockhart Parish Church, Craiglockhart Drive North, Edinburgh — photograph 4

Craiglockhart Parish Church, Craiglockhart Drive North, Edinburgh — photograph 5

Craiglockhart Parish Church, Craiglockhart Drive North, Edinburgh — photograph 6

The challenge

A century of weather had left the tower with cracked and spalling stones, a failed capital on a corbelled finial, fractured mouldings and mullions, and around seventy hairline cracks letting water into the masonry. Earlier repairs in cement mortar, and a run of indents from previous works that had been poorly bedded with voids behind them, were trapping moisture and adding to the decay. The church stayed open throughout, with services and youth groups on site, vehicle access through a narrow gate, soft ground to one side and a scaffold that had to climb the full height of the spire.

Our solution

Once the scaffold was up, our conservator surveyed the tower stone by stone and marked up every repair on the architect's elevations, so each stone could be agreed as replace, indent or conserve. Replacement stones were cut to template in our workshop from new Locharbriggs sandstone, dressed with a tooled finish to match and bedded in hydraulic lime mortar with stainless steel cramps and dowels. They included crenellations, a carved pinnacle, spire window pediments and surrounds, flying buttress voussoirs, buttress tops and a new carved head stop. Sound stones were conserved: hairline cracks injected with Paraloid B72 and sealed with a Paraloid and sand mix, fractured arrises micro-pinned, and losses rebuilt in pigmented lime mortar after all cement repairs were cut out. Joints were raked out by hand and repointed in lime. Hollow masonry was deep packed and gravity grouted with hydraulic lime and silica sand. To the engineer's design we pinned and stitched the pinnacles, stitched the tracery windows with helical bars, took down and rebuilt sections of the crenellated parapet on stainless fixings, and dowelled the earlier indents back into the wall with resin-grouted stainless dowels.