The Conservation of the 12th Century Stonework

The west and south doorways to the Church of St Mary the Virgin, Iffley, are encrusted with carvings dating from the 1160s. 

The carvings are still intact and full of detail.They have never been re-carved.

Rain, wind, and the effects of air pollution constantly erode the carvings. How can they be saved? There are three options:

If we do nothing the carvings will fade away.

If we re-carve the stone we will lose the originals. We will have a 21stcentury copy of our 12thcentury church.

If we protect the stone with a limestone spray it can be saved for the next 30 or 40 years. A temporary solution, but one that, with regular renewal, will save the carvings for future generations. 

This option was first carried out in the 1980s.  The limestone was cleaned, repaired and sprayed with a porous limestone solution that was compatible with its colour and texture. The technique had been pioneered by Professor Robert Baker at Wells Cathedral in the 1970s. He led the work at Iffley with the help of a young assistant, Sally Strachey.

Sally Strachey Ltd was chosen to undertake the renewal of the sheltercoat in 2017. 

The conservators welcomed groups of children and members of the public to climb the scaffolding and learn about the conservation process.

Here the conservator is pointing out a small crack in the figure of St Matthew over the West doorway. The crack was filled with lime mortar. This stops more water from damaging the stone. 

Carvings on the South Door that have been protected by the sheltercoat.
St Matthew and some beakheads once the sheltercoat process was completed – clean, legible and safe for the next 35 years.

The work was shortlisted for the John Betjeman Award, run by The Society for the Protection of Ancient Buildings, which celebrates excellence in the repair of places of worship.

The advantage ‘of lime mortars, plasters and paints is their “breathability”. They are the Gore-Tex of the building world, allowing water vapour out of a structure, rather than trapping it.’
Tim Radcliffe, SPAB Briefing, Lime. © 2015 SPAB

The south door of Iffley Church during the conservation process.
A plug hole where a 12thcentury wooden scaffolding pole was wedged. This is high up near the roof of the West front of the church. It has been checked for any remaining wood from the scaffolding that may cause damp penetration, and sealed with lime mortar. Sally Strachey’s team inserted a time capsule before they sealed it up.

‘Strachey’s work is the gold standard in conservation,’ Professor Heather Viles, Oxford University Rock Breakdown Lab.

St Mary’s under scaffolding
The finished west end of the church