Roof Saddle & Stack Scaffolds
Generally agreed to mean the foundation for a scaffold erected on a pitched roof, when chimneys are to be repairs. Roof saddles are generally erected when minor repairs are made, e.g. replacing chimney pots, or repointing etc.
A safe means of access or egress must always be provided, and this will usually comprise an access tower with walkway onto scaffold.
Roof Stack (illustrated below)
This type of scaffold, because of the position of the chimney, requires an access scaffold.
Roof stacks are erected where more substantial repairs are required i.e. demonstration and/or rebuilding of chimney in situation where the stack is in such a position as to make the erection of a saddle scaffold impracticable.