Ties
What is a through tie?
A through tie passes through an opening in the building — a window or a doorway — and is held by a tube on the inside face, tying the scaffold to the structure.
Use this diagram+
Free to use on your own site, in training material or in a course handout, as long as the credit link stays on it. Paste this where you want the diagram to appear.
<figure>
<img src="https://scaffoldoptix.co.uk/glossary/through-tie/diagram.svg" alt="through tie — scaffold diagram from ScaffoldOptix" width="880" height="620" loading="lazy">
<figcaption>
<a href="https://scaffoldoptix.co.uk/glossary/through-tie">What is a through tie?</a> — diagram by
<a href="https://scaffoldoptix.co.uk">ScaffoldOptix</a>
</figcaption>
</figure>It is one of the strongest tie types available, because it is a mechanical connection rather than a friction one. The inside tube cannot pass back through the opening, so the tie holds in tension as well as compression.
The trade-off is that it needs an opening, and it puts a tube across that opening — which is fine on a building site and unacceptable once the glazing is going in.
That is the practical problem with through ties: they are removed by other trades. A window fitter taking one out is the classic, and the scaffold loses a tie that nobody recorded going missing.
What goes wrong on site
- Removed by another trade and not reported or replaced.
- The inside tube too short to bear properly on the internal face.
- Relied on in an opening that is about to be glazed, with no plan for what replaces it.