When repairing or applying over old roofing felt, fibre cement and slate you should conduct the following steps to weatherproof your roofing. 

Stage 1 - Remove loose material and then scrub into the surface by brushing, a thin coat of Bitumen Primer.

Stage 2 - Fill any cracks with Bitumen Mastic.

Stage 3 - Create a top coat using either a Fast Dry Roof Waterproofer or Acrylic Roof Waterproofer. 

Using bitumen primer for flashings is an essential step in ensuring the proper adhesion and long-term performance of bitumen-based roofing materials. Bitumen primer is a specialized liquid product designed to prepare the surface and enhance the bond between the flashing material and the substrate. It is commonly used with bitumen-based membranes, such as modified bitumen or built-up roofing systems, to create a watertight seal at roof edges, parapets, and other vulnerable areas.

Using bitumen primer on walls is an effective way to prevent water penetration and protect the building from moisture-related issues. Bitumen primer is a specialized coating designed to seal and waterproof surfaces, making it an ideal choice for areas that are susceptible to water intrusion, such as basement walls, foundation walls, and exterior masonry surfaces.

Corolin corrugated bituminous roofing sheets are a popular roofing material known for their durability, weather resistance, and cost-effectiveness. These sheets are made from bitumen-impregnated organic fibers, which are compressed and then coated with bitumen to provide a waterproof and weatherproof surface. The corrugated design of the sheets adds strength and rigidity, making them suitable for a wide range of roofing applications.

Corolin roofing sheets are suitable for a wide range of roofing projects, including sheds, garages, carports, agricultural buildings, and industrial warehouses. Their versatility makes them a popular choice among builders and homeowners alike. The corrugated profile and lightweight nature of these sheets make them quick and straightforward to install. This can save both time and labour costs during the roofing installation process.

You should fit Corolin using a plywood sheet, ring-shanked nails, and a standard handsaw. Install every other corrugation, a maximum of 600mm apart lengthways. 

Available in a different choice of sheets and ridges to help suit your preferences.