Kilmorie Chapel in Argyll. A picturesque ruin.

An example of the degree of root damage to the walls.

An example of tree growing from masonry.

Degree of dilapidation and structural failure in masonry.

Reconstruction of the jambs in lime mortar and carefully selected stone.

Soft topping used at Kilmorie Chapel.

Kilmorie Chapel

Kilmorie Chapel is a late medieval structure and is the resting place of the clan MacLachlane.

Scope of works

LTM were commissioned on a negotiated contract over a three year period to undertake the repair project, working in conjunction with Martin Haddlington (Architect) and Historic Scotland inspectors.

The structure had fallen into dereliction as a consequence of losing the roof, and a great deal of the historic building fabric was suffering from major structural failures. This was clearly evident prior to the commencement of the works as shoring had been used to resist the collapsing masonry. The project team believed that the most sympathetic, technically sound and aesthetically acceptable solution was to stabilise and consolidate the masonry. No attempt was made to restore the structure and it was decided to leave the building as a picturesque ruin.

Technical and philosophical solutions

The level of deterioration was so great that the structural stability of primary sections of the building were in imminent danger of collapse. This included the rotation of the gable with subsequent detachment from the flank walls, collapse of main elements and components such as windows and doors openings and buckling of the masonry walls. It was therefore deemed necessary to undertake emergency shoring works to simply to prevent total failure of the structure occurring.

Substantial vegetation growth was common place throughout the building, with numerous trees growing from the exposed wall head, the largest having a trunk diameter of approximately 300mm. These trees obviously had correspondingly large root systems that created displacement and failure of the masonry. Compounding this problem deterioration of the original lime mortars had occurred due to years of water washing through the exposed wall heads.

Stabilising and consolidating a structure in such a state of disrepair is extremely challenging and many considerations must be given to both the technical and philosophical issues that will undoubtedly be encountered. The approach that was undertaken included; shoring and emergency works, recording and documentation of the existing building fabric, sensitive down taking and vegetation removal, rebuilding masonry in lime mortars following the line of root removal, reconstruction of the door and window rybats in lime mortars, structural tying with high grade stainless steel anchors as necessary, soft topping of wall heads adopting indigenous species of grass to consolidate and protect the exposed wall heads. Soft topping is the process of capping exposed wall heads with a layer of puddle clay that is bonded into the masonry substrate. Turf was laid on top of this layer of clay and prevents excessive moisture penetrating into the wall head. This type of repair may be seen as an aesthetically, and techcally acceptable method of finishing ruinous buildings.

Logistical and site considerations

As the site is the resting place for the Clan MacLachlan it was necessary to incorporate a high degree of site protection to guard against damage to the monuments. In addition, respect for the grave yard and monuments were always of prime importance. It must however be emphasised that all LTM projects are undertaken with a high degree of consideration for the clients requirements and respect for the building itself.

Project

Kilmorie Chapel, Argyll.

Client

Clan MacLachlan Society.

Architect

Martin Haddlington.

Consultant

Ted Ruddock Structural Engineers.

Solutions

Emergency shoring. Stabilising and consolidating masonry structures. Reconstruction of the door and window rybats in lime mortars. Vegetation removal and soft topping of wall heads adopting indigenous species of grass to consolidate and protect the exposed wall heads.