Understanding the Lower Edge of a Pitched Roof Truss

The question asks for the specific name given to the lower edge of the inclined surface of a pitched roof truss. To answer this, we need to understand the different parts of a roof structure, particularly a pitched roof supported by trusses.

What is a Pitched Roof and a Roof Truss?

• A pitched roof is a roof that slopes downwards in two parts from a central ridge, forming a gable at each end.
• A roof truss is a structural framework, typically triangular, used to support a roof, bridging the space above a room and providing support for the roof deck.

Analyzing the Options

Let's look at the given options and their definitions in the context of a roof structure:

1. Gable: This refers to the triangular upper part of a wall at the end of a pitched roof. It is not the lower edge of the roof surface.
2. Rise of truss: This is the vertical distance from the bottom chord (base) of the truss to its peak. It's a dimension, not a structural edge.
3. Hip: This is the external angle formed where two sloping sides of a roof meet. It is an edge, but it's a sloping edge where two roof sections join, not the lower horizontal edge.
4. Eaves: This is the part of the roof that hangs over the wall of the building. It is specifically the lower edge of the roof surface where rainwater typically drains off the roof.

Identifying the Lower Edge of the Inclined Roof Surface

Based on the definitions, the term that describes the lower edge of the inclined roof truss surface of a pitched roof is the eaves. The eaves form the boundary between the roof and the wall below and often extend outwards to protect the walls from rain.

Therefore, the correct term for the lower edge of the inclined roof truss surface of a pitched roof is the eaves.