Editing Scaffolding (section)

===Ties===
[[File:Holy Trinity Vladimir.jpg|left|thumb|The Holy Trinity Church in [[Vladimir, Russia|Vladimir]], with scaffolding wrapped in safety mesh]]

Scaffolds are only rarely independent structures. To provide stability for a scaffolding (at left) framework ties are generally fixed to the adjacent building/fabric/steelwork.

General practice is to attach a tie every 4 m on alternate lifts (traditional scaffolding). Prefabricated System scaffolds require structural connections at all frames - i.e. 2–3 m centres (tie patterns must be provided by the System manufacturer/supplier). The ties are coupled to the scaffold as close to the junction of standard and ledger (node point) as possible. Due to recent regulation changes, scaffolding ties must support +/- loads (tie/butt loads) and lateral (shear) loads.

Due to the different nature of structures there is a variety of different ties to take advantage of the opportunities.

''Through ties'' are put through structure openings such as windows. A vertical inside tube crossing the opening is attached to the scaffold by a transom and a crossing horizontal tube on the outside called a bridle tube. The gaps between the tubes and the structure surfaces are packed or wedged with timber sections to ensure a solid fit.

''Box ties'' are used to attach the scaffold to suitable pillars or comparable features. Two additional transoms are put across from the lift on each side of the feature and are joined on both sides with shorter tubes called tie tubes. When a complete box tie is impossible a l-shaped ''lip tie'' can be used to hook the scaffold to the structure, to limit inward movement an additional transom, a ''butt transom'', is placed hard against the outside face of the structure.

Sometimes it is possible to use ''anchor ties'' (also called ''bolt ties''), these are ties fitted into holes drilled in the structure. A common type is a ring bolt with an expanding wedge which is then tied to a node point.

[[File:Scaffolding Waverley Station.jpg|thumb|Scaffolding by Balfour & Beatty during refurbishment of the Waverley Station roof, Edinburgh 2011]]
The least 'invasive' tie is a ''reveal tie''. These use an opening in the structure but use a tube wedged horizontally in the opening. The reveal tube is usually held in place by a reveal screw pin (an adjustable threaded bar) and protective packing at either end. A transom tie tube links the reveal tube to the scaffold. Reveal ties are not well regarded, they rely solely on friction and need regular checking so it is not recommended that more than half of all ties be reveal ties.

If it is not possible to use a safe number of ties ''rakers'' can be used. These are single tubes attached to a ledger extending out from the scaffold at an angle of less than 75° and securely founded. A transom at the base then completes a triangle back to the base of the main scaffold.