11.8 How to Build a House Roof: Roof Size Calculation

Building the roof of a house is a task that requires planning, precision and technical knowledge. The first step in this process is to calculate the size of the roof. This calculation is crucial in determining the amount of materials needed and ensuring the roof is constructed correctly and safely.

Roof Size Calculation

In general, roof area is calculated in square meters (m²). To calculate the roof area, you need to know the floor plan of the house and the slope of the roof. The formula for calculating roof area is: Roof Area = Floor Plan Area x Roof Slope.

Floor Plan Area

The floor plan area is the total area of ​​the home, including all interior and exterior walls. To calculate the floor plan area, you need to measure the length and width of each room and then add all these areas together. Remember to include hallways, bathrooms, closets, and any other areas that may be covered by the roof.

Roof Slope

Roof slope is the measure of the angle of the roof relative to the ground. Roof slope is expressed as a ratio such as 1:3, which means that for every horizontal meter, the roof rises 0.33 meters. Roof pitch is important because it affects the amount of materials needed and the amount of work required to build the roof.

To calculate the roof pitch, you need to measure the height of the roof at the highest point and the horizontal distance from the highest point to the edge of the roof. The formula for calculating roof slope is: Roof Slope = Roof Height / Horizontal Distance.

Additional Considerations

In addition to floor plan area and roof pitch, there are other considerations to take into account when calculating roof size. For example, if the house has multiple levels or if the roof has multiple sections with different slopes, you would need to calculate the area of ​​each section individually and then add those areas together to get the total roof area.

In addition, it is important to take into account the overlap of roofing materials. Most roofing materials such as shingles or sheet metal are overlaid to ensure the roof is waterproof. The amount of overlap varies depending on the type of material and the slope of the roof, but is generally around 10% to 20% of the total roof area.

In conclusion, calculating the roof size is a crucial step in building a roof. This calculation helps determine the amount of materials needed and ensures the roof is constructed safely and efficiently. When calculating roof size, it's important to consider the floor plan area, roof pitch, and any additional considerations such as multiple levels or overlapping materials.