Report on Conservation works undertaken on the Dovecote, Bruton.

November 2010.

Contractor: René Rice.

Client: The National Trust.

1. Introduction.

The history and general description of the building are more than adequately covered in the archeologist’s report so they will not be entered into here except where necessary to provide background information about conservation choices made during the project. The most salient point is that the four sided tower, once roofed now has no roof leaving exposed wall tops on the four gables, three of which remain.

The second most salient point in relationship to choices of scope and method of the works relates to budget. A full top to bottom, interior and exterior conservation project was not possible and budgetary restrictions limited the work to the top third of the tower with special emphasis on cappings and the stitching of cracks/bulges.

Pre-contract photographs can be found in the pre-contract photographic survey folder on the disc.

2. Scope of the Works.

2.1. Gable crosses

2.1.1 West gable

All hollow joints were filled- methods and mixes dependent on scale of fissure. Areas of the concrete capping beneath the gable cross were cut out and replaced.

2.1.2. South gable

All hollow joints were filled- methods and mixes dependent on scale of fissure. Areas of the concrete capping beneath the gable cross were cut out and replaced.

2.1.3 East gable

All hollow joints were filled- methods and mixes dependent on scale of fissure. Areas of the concrete capping beneath the gable cross were cut out and replaced.

2.2. Cappings: concrete

2.2.1. Cutting out and replacing loose concrete capping.

North (truncated)gable

East gable

Junction of north and west gables

south west corner

2.2.2. Drilling through capping and grouting wall top.

After pointing up localized walls to avoid grout runoff 25mm holes were drilled through the concrete capping and grout composed of nhl 3.5 hydraulic lime and sharp sand with water was introduced via funnel into the holes. In total some 15 buckets of grout were poured into the wall tops.

2.3. Vegetation removal and subsequent masonry rebuilding.

All woody growth was removed from the building and areas were dismantled where necessary to chase out roots, esp in the north west corner.

2.3.1.a North west corner

Subsequent to the last picture above the Elder root to the bottom left was cut out and minor roots drawn from the interior of the masonry. All stones had been stored in order and were rebuilt in reverse order.

The exterior facework of the north (truncated) gable was poorly bonded to the core so 8mm stainless threaded bar was inserted and resined into joints as the internal masonry build progressed. In all 3no bars were fixed as the build progressed.

Rebuild:

Subsequent to the rebuild of the masonry and the repositioning of the original reclaimed stone roofing the area was recapped with concrete to match the existing. (see photograph above)

2.4. Works to masonry surfaces

2.4.1. Grouting small cracks with syringe and clay birdsnests using St Astier Coulinex grout. (Coulinex product information sheet on disc.)

Mix: Approx 1 Coulinex to 0.8 part water.

It was not always easy to introduce grout into the smallest of the cracks but where possible a catheter syringe was used with a clay seal. Where gravity feed was possible, clay birds nests attached to the masonry were filled with liquid grout which was encouraged to flow into the pre-wetted crack.

2.4.2. Grouting larger cracks using grouting gun and soft sand with nhl 3.5

For the larger cracks of 4mm and above a grout gun was used with a 5mm nozzle using a mixture of soft sand and St. Astier nhl 3.5 hydraulic lime. This was mixed to a gunnable consistency with water mechanically in a clean bucket.

At the highest levels, most exposed, the nhl 3.5 was substituted with nhl 5.

Mix: 1 part nhl 3.5: 2 parts soft yellow sand : water

2.4.3. Pointing and joint filling using coarse hydraulic lime mortar mix

Larger open joints and other lacunae were filled with coarse lime mortar in normal pointing style.

Mix: 1 part nhl 3.5: 2 parts Chardstock sand: 1. Part Bath Stone Dust washed: 0.25 part crushed coal

(this started out as 2 parts Bideford grit: 1 part Portland Dust: 0.25 parts crushed coal but this was too grey and too coarse)

At the highest levels, most exposed, the nhl 3.5 was substituted with nhl 5.

2.5. Insertion of Cintec ties.

Six ties were inserted in the eastern corner of the south wall where there was a pronounced bulge in the masonry (See Mann Williams report)

2.5.1. South Wall east corner

North wall west corner

2.5.2. A further two ties some 2m in length were inserted into the north wall at it’s abutment with the west wall to tie the two walls across a vertical crack ( see Mann Williams report)

The works extended from the apex of the gables to a point some 6 metres below both interior and exterior.