The roof slopes in one direction. Lean-to-roof is a special case of monopitch roof - it has a single pitch that rests against a higher wall.

Monopitch roof, Mexico (S. Brzev)

Monopitch roof, Canada (S. Brzev)
The roof slopes in one direction. Lean-to-roof is a special case of monopitch roof - it has a single pitch that rests against a higher wall.

Monopitch roof, Mexico (S. Brzev)

Monopitch roof, Canada (S. Brzev)