Implementation conditions for the approach to façades in the historic city centre

0. General

1. Any new elements to be added must be incorporated in such a way that they do not affect the historic design or detailing (for example, new shop fronts must be consistent with the façade above);
2. All parties involved in the preparation, planning, execution and supervision of the works (owner, architects, site supervisors, contractors, site managers, subcontractors, etc.) must be made aware of these implementation guidelines before work commences
3. If any historical architectural remains or finds of archaeological interest are discovered during the works, the council must be notified as soon as possible. The finds must not be moved or destroyed without the council’s written consent.

THE FOLLOWING TECHNICAL SPECIFICATIONS APPLY ONLY TO THE
HISTORICAL FACADE ELEMENTS.

1. Bricklaying, pointing and plastering

1. Facade cleaning is not permitted;
2. The application of water-repellent treatments to façades is not permitted;
3. The use of stone stabilisers is not permitted;
4. Any repairs to the brickwork must be carried out using matching bricks, taking into account colour, hardness, size and bond;
5. The composition must be adapted to the hardness of the stone;
6. The new jointing must match the existing work in terms of colour and finish;
7. To ensure proper adhesion of the grout, the joints must be chiselled out to a depth of at least 2.5 cm. This chiselling must be carried out exclusively by hand or, if using pneumatic tools, with a fine chisel. Grinding out the joints is only permitted using the smallest possible angle grinder (preferably fitted with a dust extraction system) to avoid potential damage to the stone;
8. When removing existing jointing, narrow butt joints must not be widened;
9. Chiselling out butt joints is not permitted;
10. The composition of the plasterwork must be adapted to the hardness of the underlying stone and, in terms of colour and finish, to the existing work;
11. The use of decorative plaster is not permitted without the written consent of the council or the necessary permit.

2. Carpentry

1. The wooden components to be replaced must be restored in a historically accurate manner, using the existing detailing and design—where these are correct—as a starting point;
2. The details must be submitted to the council for approval before work commences;
   a. The wooden components to be replaced must be of the same weight and profile as the existing ones. Samples of the existing wooden components must be retained for inspection;
   b. the types of timber to be used must be consistent with the existing work;
3. Tropical hardwoods should be used as little as possible. A good alternative is ‘Oregon Pine’, “Clear and better” grade;
4. The use of plywood, plastic, fibreboard bonded with plastic and similar sheet materials for the repair of gutters, wind braces, decking boards, and façade and roof boarding is not permitted;
5. Holes in wooden gutter bases intended for zinc or copper gutter cladding must be 0.5 cm wider than the stud bolts in question.

3. Painting

1. Before work commences, the following must be submitted to the council for approval:
   a. proposal for the choice of colour; this proposal must be historically accurate;
   b. proposal for a paint system.
2. The painting work must be carried out in accordance with the provisions of the basic painting specifications (maintenance and new construction);
3. The areas to be painted must be properly primed;
4. Plasterwork or natural stone must only be painted using a paint that dries to a smooth finish. Due to the moisture management within the structure, the paint system must be adapted to the type of plasterwork or natural stone to be painted. The use of decorative plaster is not permitted without the written consent of the council or the necessary permit;
5. Sealing gaps and cracks in façade joinery;
6. These must be filled and finished to a smooth finish using a two-component filler;
7. Joints between window frames and brickwork or between window frames and natural stone must not be sealed using PUR foam or sealant;
8. Filler should be used sparingly.

4. Natural stone

1. The natural stone to be used must be worked using traditional methods such as chiselling, grinding and the like;
2. Any natural stone components or structures to be replaced must be carried out in accordance with existing, historically accurate detailing. Details must be submitted to the council for approval prior to the commencement of the works;
3. The impregnation and application of stone hardeners to façades, façade elements and ornaments is not permitted.

5. Miscellaneous

1. The glasswork must fit into the existing historic window;
2. When maintaining or repairing wrought iron components such as façade anchors and other ornamental ironwork, all ironwork must be completely stripped of old paint layers and rust.