R4 Roofing systems consist of multiple components that make up the topmost layer on buildings. The most important components of the roof are the following:

- Rafters – these elements make up the frame and foundation of the roof;

- Sheathing – this part consists of flat sheets nailed to the rafters to support the higher layers;

- Flashing – metal sheets installed in areas where two roof slopes meet and the structural integrity of the roof is compromised. The purpose of the flashing is to reinforce sensitive roof areas;

- The roofing material – asphalt shingles, metal sheets, clay and concrete tiles are the most common materials used for covering roofs;

- The fascia – the finished edges of the roof that hold the gutters and connect the eaves to the building;

- Roofing vents – the openings on the roof that serve the purpose of ensuring the ventilation of the area underneath the roof, more precisely, of the attic. Most roofs include two vents, one for inlet, at the base of the roof and another one for outlet, located at the top of the roof, near the ridge;

- The gutters and downspouts – components that are adjacent to the roof and serve the purpose of directing water away from the roof surface.