Specification Guidelines
Important: The applicant, or the applicant's agent, should make sure that these guidelines are drawn to the attention of the contractor(s) that tender for and will carry out the work. Work carried out to other specifications will not be eligible for grant, unless with prior agreement of Angus Council.
Section 1: Roof Works and High Level Repairs
The roof is nearly always a dominant feature of a building and the retention of its original structure, pitch, cladding and ornament is important. Restoration of original elements or materials is encouraged. Such work should always be based upon firm evidence. Roof works should be of a comprehensive nature and any necessary associated repairs (to the roof structure, chimneys, and leadwork or rainwater goods) should be undertaken at the same time.
Re-slating
Slated roofs have a visual quality that contributes significantly to the character and architectural quality of buildings. When recovering, the roof should be photographed prior to stripping to ensure that the existing details are properly followed. Re-slating should be carried out re-using as many sound existing slates as possible, augmented with new natural slates to match the existing, laid in diminishing courses fixed with copper or stainless steel nails over breathable underslating felt. Reclaimed and new materials should not, however, be mixed together on the same pitch. The slates should be of British origin and appropriate to the area. Detailing should be reinstated carefully to the original form, particularly at eaves, ridges and verges. Existing ridge and hip tiles or slates should be retained and re-set where possible, or should be replaced to match the existing. New lead flashings should be provided at all abutments and chimneys. Provision should be made for ventilating the roof space(s) by an agreed method. Stone slates have been mostly replaced by Welsh slates. Where stone slates remain they should be repaired using salvaged Angus slates.
Chimneys
Chimneyheads should retain their original character whether they are predominantly brick, harled or sandstone. Where chimneyheads have been taken down, or rebuilt in an inappropriate material they should be reinstated to the original design. Original details, including the style of chimney pots, should be reinstated wherever possible.
Leadwork
All flashings, soakers, cappings, valley and gutter linings and other weatherings should be in lead, to the weights and details recommended by the Lead Sheet Association, as described in the 'Lead Sheet Manual'. Unless otherwise agreed by Angus Council, flat roof coverings, including those on internal wells and dormer windows, should also be in lead. Appropriate provision should be made for ventilation below lead, particularly where thermal conditions are likely to change.
Rainwater Goods
Generally, any new or replacement rainwater goods required should be in cast iron, to the original pattern. In overhauling cast iron rhones and downpipes they should be thoroughly de-rusted, primed and re-painted. Metal gutter brackets may often be faulty, and these should be checked and replaced if required. Rainwater goods originally of a different material, such as lead, stone or timber, should be replaced accordingly, unless otherwise agreed. Check the sizing of rhones and downpipes for signs of persistent overflowing, and enlarge as required to increase the capacity. The integrity of the original design should be adhered to and traverses should be avoided. Rhonepipes should be fitted on spacers or holder-batts far enough from the wall that if a leak should occur water will run down the back of the pipe and not down the wall.
Structural Timber Repairs
Repairs to structural timber should be carried out using traditional methods, retaining all sound material and replacing only what is necessary to restore structural integrity. Badly decayed or seriously split members should be carefully cut away and new sections spliced in, using timber of the same species and scantling as the original, oak used in repairs should preferably be new home grown oak. A detailed specification and drawings should be approved for the repair of a timber-framed building or historic roof structure before any work is undertaken, and these will be based on a comprehensive survey of the existing structure. Specialist advice should be sought concerning any existing timber carrying decoration likely to be of historic importance. An appointed structural engineer should approve any mechanical repair methods proposed to structural timbers. Large sections of timber required for replacement should not be formed by laminating smaller sections. In situ resin repairs to structural timbers are not acceptable, and it is important to maintain flexibility at joints to allow for some movement in the frame.
Section 2: Masonry and Harling
Stonework Repairs
Brechin's buildings are predominantly built out of local sandstone. Repairs to stonework and brickwork should be carried out in materials to match the existing exactly. Stone should be obtained where possible from the same quarry as the original. Stone that has lost its structural quality or is badly decayed should be carefully cut out and matching stone pieced in. Replacement stone should be cut to the full dimensions of the existing blocks, unless otherwise agreed and face patches should never be less than 100mm deep. Samples of any new stone to be used should be approved. The face of new stone should be tooled to match the original unweathered finish. Stone should always be laid on its natural bed, unless otherwise specified and new stonework should be laid to match the existing wall. All replacement stone details should be cut accurately to the original pattern and profile; this is particularly important for architectural features. Where the existing stone is exceptionally eroded, replacement details should be agreed before work starts. Dressing off should be limited to the removal of dangerous or loose material and should be carried out with a bristle brush. Areas of unsound stonework should be carefully rebuilt as agreed, re-using as much of the existing stone as possible. The inclusion of any cement in the mortar mix for the bedding should be avoided. Bag lime with a mix to the proportion of 1 lime to 2-3 aggregate is likely to be appropriate. Unless otherwise approved, resin-based in situ plastic repairs to stonework are not acceptable.
Re-pointing
Re-pointing should only be undertaken where mortar has weathered out, leaving open or where deeply recessed joints vulnerable to water penetration or where the mortar is very soft and loose. Mortar should never be removed forcibly by the use of a mechanical disc cutter or other unsuitable methods, which are likely to cause damage to arrises or increase the width of joints. The use of this technique could prejudice grant-aid to other eligible work. Loose pointing should be carefully raked out manually to at least 35 mm or twice the width of the joint to a square profile. For the re-pointing of finely jointed work (which is rarely necessary), a hacksaw blade held manually is a suitable tool for cleaning out the joint. The removal of hard, cement rich mortar should be carried out with great care and should not be attempted if it will cause more damage to the fabric than if the hard mortar is left until it has loosened sufficiently to allow easier removal. Mortar used for re-pointing should be slightly weaker than the stone. For this reason the inclusion of any cement in a mix should be avoided and a bag lime mix to the proportion of 1 lime to 2-3 aggregate is likely to be appropriate. Sometimes it may be necessary to remove small stone pinnings when raking out, but these should be replaced during tamping and pointing. All pointing should be done accordingly to the character of the individual building and subject to approval.
External Cleaning
Any external cleaning of stonework, if agreed to be appropriate should be carried out to an approved detailed specification. Cleaning should always be undertaken by a specialist conservation contractor. No abrasive or high pressure cleaning techniques should be used, particularly unregulated grit or sand blasting. Cleaned surfaces should not be treated with any form of sealant or silicone water repellent. If external cleaning is proposed as part of a programme of repair and rehabilitation, early discussions with the Project Manager are essential. Undertaking unapproved cleaning works may jeopardise other grant eligible works.
Harling and Rendering
Renders or harling should not be removed in order to expose, for example, rubble stonework, which was not intended to be exposed, nor should it be removed where there are good reasons for render having been applied at a latter date. There may also be cases, however, where the later application of render detracts from the proper character of a building and damages the original design intention. If so, and subject to accurate evidence of the original appearance, the removal of render may be considered acceptable. It should be noted, however, that it might be necessary to carry out repairs to the original underlying material following the removal of the render that, if considerable, may make the proposal impractical and costly. Any appropriate proposal to re-render or harl a building with lime will be encouraged and should be discussed with the Project Manager at the earliest opportunity.
Section 3: Repair/Reinstatement of Joinery and Reinstatement of Architectural Features
Windows
Existing original timber sash and case windows should be retained and carefully repaired wherever possible. If replacement is unavoidable, the new windows must be exactly matching timber sash and case windows and maintain or reinstate the existing original astragal pattern and profiles using site and/or documentary evidence. Existing plate or crown glass should be retained and re-used in new windows, as replacement with modern float glass will always adversely affect the appearance. New window furniture should be to the original pattern. Permanent ventilation where required should be provided discreetly. Only linseed and sand mastic should be used. New and/or repaired joinery should be painted with gloss paint and not stained.
PVC and aluminium replacement windows, whether single or double-glazed, are not appropriate replacements and are therefore not grant eligible. The introduction of draught stripping and bringing back shutters into use is commended as a much more appropriate method of achieving thermal comfort. Wherever possible PVC, aluminium, modern timber casement, pivot windows should be returned to the original material and design.
Doors and Fanlights
Wherever possible original doors should be repaired by piecing and patching-in new timber of the same kind to replace rotten or damaged parts. If replacement is unavoidable, it must match the original exactly. If the original has been lost, replacements must be of appropriate traditional design and materials.
No factory made aluminium or timber glazed, flush (unless traditional flush beaded) or flush doors with applied mouldings are eligible. Proprietary catalogue doors must be strongly resisted as inappropriate to historic buildings. Doors should be painted with gloss paint and the ironmongery should be of simple traditional design.
Fanlights must be retained and repaired where they exist. Re-instatement of lost fanlights to match the original pattern is strongly encouraged.
Ironwork
Decorative ironwork, such as balconies, canopies or railings, should be carefully repaired or reinstated accurately to the original pattern and detail. Photographs or drawings should record existing decorative ironwork requiring repair or replacement before works starts, and the existing paint finish analysed to determine the original colour scheme. Drawings for new/replacement ironwork will be required for approval. New or repaired ironwork should be painted with gloss paint to the original colour scheme. Any alternative colour scheme proposed should be agreed.
Internal Works
Internal works might be grant eligible if necessary for the structural integrity of the building or in context of grant aided external work.
External Works
Boundary walls, fences and gates should be repaired to match existing, or reinstated to the original design. The installation and design of any new such elements must be approved in advance.
External paving should be laid in appropriate natural materials, such as Caithness stone or granite/whin setts, to match the existing where relevant and laid in the traditional manner.
A detailed scheme for any external landscaping proposed, including any planting, lighting, signage and street furniture should be submitted for approval.
Special Features or Materials
Where unusual features or materials special to the building exist or are required, the specification for their repair or reinstatement should be agreed.
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