A roof system is a complex assembly of different components that work together to protect a building from the elements, provide structural integrity, and contribute to energy efficiency. Here's a breakdown of how it generally functions:

1. Shedding Water:

• The primary function of a roof is to shed water (rain, snow, ice) away from the building's interior.

• This is achieved through the slope of the roof, which allows gravity to pull the water downwards.

• The outermost layer of roofing material (shingles, tiles, metal, membrane, etc.) acts as the first line of defense, creating a water-resistant barrier. The specific design and overlapping installation of these materials prevent water from penetrating.

• Flashing, made of metal or rubber, is installed at vulnerable areas like roof edges, valleys, chimneys, vents, and walls to direct water away from these intersections and prevent leaks.

2. Structural Support:

• The entire roof system is supported by the underlying roof structure, which typically consists of rafters (sloping beams) or trusses (engineered frameworks).

• Roof decking or sheathing (usually made of plywood or OSB) is attached to the rafters or trusses, providing a solid surface for the other roofing materials to be installed upon.

3. Protection Against the Elements:

• Beyond water, the roof system protects against wind, sun, and temperature fluctuations.

• The outer roofing materials are designed to withstand wind uplift and impact from hail or debris.

• The materials also offer some resistance to UV radiation from the sun, which can degrade roofing components over time.

4. Ventilation:

• Proper roof ventilation is crucial for regulating temperature and moisture levels in the attic and under the roof deck.

• Intake vents (usually located in the soffit or lower part of the roof) allow cooler, dry outside air to enter the attic.

• Exhaust vents (typically at or near the roof's ridge or higher points) allow warm, moist air to escape.