6th topic

If we need to cover a rectangular building, we can do it with one, two, three, or four planes (slopes).

A roof can be categorized according to the number of its sides: single-pitched, double-pitched, three-pitched, four-pitched. These terms are also sometimes used to name roof types.

This exercise will help you to learn more about roof types.

Characteristic elements of a lean-to roof (single-pitched). Horizontal and slope lines are shown in Pic. 6.13. 

A gable roof (double-pitched) (Pic. 6.14) consists of two planes whose horizontals are parallel.

If the angle of inclination of the roof planes are the same, then the line of intersection of the planes (roof ridge) is parallel and equidistant from the horizontals at the same height. As the roof height changes, the top view does not change.

A hip roof (four-pitched) is the intersection of two planes having the same slope.

If the angle of inclination of the roof planes are the same, then the horizontal projection of the line of intersection of these planes will be the bisector of the angle formed by the horizontals of the roof planes (Pic. 6.15).

Construction of a cross-hipped roof (Pic. 6.16). All roof planes have the same slope. All eaves are at the same height.

All lines of intersection of the roof planes are either perimeter bisector lines (red) or lines parallel to opposite perimeter lines (blue). 

Black arrows indicate slope lines.

Find the gable roof projections. Click on the correct image(s).

Roof construction checkpoints (Pic. 6.17). 

• A bisector is constructed for each perimeter angle (Pic.6.17, a).

• If the perimeter lines are parallel, the line of intersection of the corresponding roof planes is parallel to them and located midway between them (Pic.6.17, b). 

• Three or more intersection lines of the roof planes intersect at one point (Pic.6.17, c).

• Arrows are positioned in the direction of the line of inclination of the roof plane, perpendicular to the horizontal perimeter of the roof plane (Pic.6.17, d). The arrows must not point in opposite directions!