One is the afore-mentioned free-standing wall, another twenty foot wall is attached to the side of a building and is used when inclement weather prevents use of the large tower.
Donations should be taken directly to a charity shop during opening hours, as goods left on the street may be stolen or damaged by passers-by or inclement weather.
In inclement weather conditions, the ability to quickly erect and enclose the building allows workers to shelter within and continue interior finishing.