Repairs to South Porch stonework
The limestone porch of Holy Cross Church Byfield Northants, dates from the 15C. The several arched entrance has ball flowers to middle arch moulding, a crocketed ogee hood and pinnacles, with a shallow niche with an ogee hood above. The condition of some of the carved stonework was deteriorating and in danger of collapse and with it the loss of centuries of historic detail.
Please click on each photograph for more information.
Work commenced in July 2020.
Structural cracking due to delamination and edge bedded stone.
The central head is limestone, the other two are cement replacements, decaying stonework beneath.
The stone was very friable, delaminated and on the verge of collapse.
Voids and cracks in the stonework caused by stones laid out of bed.
The arch was severely cracked.
Helical stainless steel pins were used to secure the base.
One tie is shown pulled back to demonstrate the required depth of the ties.
3mm and 4mm copper and stainless steel pins were used to pin sections together.
Photo shows lime being grouted into primed cracks. On the left, cotton wool and clay are used to seal adjacent cracks which also helps to monitor grout flow, force it vertically and to fill all the voids. All sections were pinned together or back to the main stonework. Initially it was necessary to pin using resin as an immediate bond was required. But where possible a lime putty was used in conjunction with copper threaded dowels.
Samples of lime mortars were made using different aggregates for mortar repairs and repointing.
Completed repairs to the pinnacle feature.
Completed repairs to the arch stones.
Work to the stone hood above the Niche
Cracks to hooded niche above the arch.
Because of the shape and thinness of the canopy of the hood it would be extremely difficult to pin without risking damage and collapse. So alternative methods of support and repair were used.
Arrows point at the niche detaching from the main wall. This area was pinned and grouted.
Completed work. All cracks have been lime grouted and pointed with a matching mortar.
Left side: Detached stone now pinned back, grouted and repointed.
Right side: All cracks grouted and pointed with matching mortar.
Work to the underside of the stone hood
1st Stage. s/steel mesh ties fixed across internal cracks. The front section was on the verge of falling.
2nd stage. 8mm s/steel mesh fixed with screw and washer and held in place with Plaster of Paris. The mesh was designed as a wedge, so it is holding itself in place and is incapable of falling. It is holding the cracked canopy up and in position. A matching lime render was applied on top of the Plaster of Paris so the repairs will not be seen.
Final Stage: A lime render mortar was applied over the Plaster of Paris (difficult to see for shadows) which when set, was toned down in colour to match the adjacent stonework.
Additional Repairs
Within the same decorative features on the South porch of Holy Cross Church Byfield Northants, were similar faults within the masonry. Cracks and detached sections were likely to cause failure and loss of important features within a couple of years.
The decorative feature beneath the hooded niche was detaching and cracked, areas highlighted by white arrows.
3mm stainless steel pins were used (approx. position highlighted by white arrows) to attach it to the main body of the feature. Cracks were grouted with a lime putty grout and then pointed with a matching mortar.
Feature pinned, grouted and pointed.
A decorative head was cracking and becoming detached from the main stone. A white arrow highlights location of the crack. A 3mm s/steel pin was used to secure the head, then the void behind the head was grouted and pointed.
The repaired head from the front.