An offset ridge glasshouse or orangery is usually built against a high wall, but can also be free standing. They are attached to the wall using a valley gutter which is wide enough to walk in for ease of maintenance.
Lean to bespoke glasshouse with offset ridge 4.5m x 4.6m
Lean to offset ridge glasshouse with porch 35° pitch roof 2.6m x 8.3m