A roof cornice is a decorative horizontal molded projection located above the frieze and beneath the roof's eaves. While it offers decorative value, the cornice also keeps rainwater away from the building’s walls. In general, demand for repair comes into play on old or historic buildings, and it can be challenging due to the complexity of the building’s design and the presence of rich ornamentation. Therefore, repairing a roof cornice is a time consuming job and requires some experience, skills and patience. The extent of the repair will depend mainly on the age of the building and the material of the cornice, like metal, wood, terracotta or PVC. Follow the instructions below for a successful roof cornice repair.
Step 1 – Initial Visual Examination
Examine the exterior and the interior of the cornice in order to determine the extent of damage. Locate the sections that are in need of repair. Depending on the height of the building, erect a fixed scaffolding tower to facilitate inspection.
Step 2 – Close up Inspection
Start by inspecting the protective coating of the cornice. If the building is historical, most probably there will be an ornamental layer of zinc. Check if all layers are intact. Determine the condition of each ornamental element and pay close attention to the joints soldering the elements. Look at the modillions (the ornamental brackets supporting the cornice) which are usually in the form of a scroll or a plain block.
Modern types of roof cornices used in residential or public buildings are much simpler and the inspection won’t take as long.
Step 3 - Repair Roof Cornice
Once you have evaluated the present condition of the cornice, you are ready to start with the actual repair. Full scale repair projects may include the following:
- Remove the flaking or loose paint from the components of the cornice. Consider water spray and heat removal methods rather than chemical removal due to environmental and public safety reasons. Should you choose to use the water spray removing technique, be sure to prevent water collecting inside the cornice as it will destroy the cornice over time.
- Restore the ornamental layer of zinc. The process includes removal of any damaged or deteriorated tand moldings followed by installation of new ones. If new zinc ornaments closely resembling the original ones are hard to find, consider recreating them, especially if a more authentic repair is what you aim at. Examine the condition of the soldered joints between the zinc ornaments.
- Install new cornice edge details and new roofing on the top of the roof cornice. Use a backing of galvanized steel to attach the repaired cornice to it. In case the cornice needs another repair in the future, that will help you remove it.
- Repaint the exterior and interior of the roof cornice. Before you apply finish paint, use zinc oxide or zinc dust primer to prevent the formation of rust.