A buttress is an architectural structure built against or projecting from a wall which serves to support or reinforce the wall. Buttresses are fairly common on more ancient buildings, as a means of providing support to act against the lateral (sideways) forces arising out of the roof structures that lack adequate bracing.
Cavity walls consist of two 'skins' separated by a hollow space (cavity). The skins are commonly masonry such as brick or concrete block. Masonry is an absorbent material, and therefore will slowly draw rainwater or even humidity into the wall, as well as from the inside of the house as from outside.
A curtain wall system is an outer covering of a building in which the outer walls are non-structural, utilized to keep the weather out and the occupants in. Since the curtain wall is non-structural, it can be made of lightweight materials, thereby reducing construction costs.
At that end of Minor Canon Corner the shadow is profound in the existing state of the light: at that end, too, there is a piece of old dwarf wall, breast high, the only remaining boundary of what was once a garden, but is now the thoroughfare.
A green wall is comprised of plants grown in supported vertical systems that are generally attached to an internal or external wall, although in some cases can be freestanding. Like many green roofs, green walls incorporate vegetation, growing medium, irrigation and drainage into a single system.