ScaFixGuide
Scaffold ties and anchoring explained
A facade scaffold stands up because it leans on the building at regular points. This guide shows how far apart those points are in real manufacturer instructions, how much force each one carries, how anchors are proof-tested in the UK, and what OSHA sets for the US.
By Ole Emil Frikstad Urstad · How the numbers are computed ·
What are scaffold ties and how many does a scaffold need?
Ties connect the scaffold to the building so it cannot buckle or blow over. The number comes from the manufacturer’s instructions, TG20 or a design, not a rule of thumb. Typical manuals space ties no more than 4 m apart vertically, often in a staggered pattern, and 2 m with a tie at every node once the scaffold is sheeted.
Why does a scaffold need ties at all?
A facade scaffold is a tall, narrow frame. On its own it would tip away from the wall under wind or an eccentric load, and its long standards would buckle under weight. Ties hold the inner standards at fixed points, which shortens the length that can buckle and stops the whole structure rotating outwards. HSE’s guidance is blunt about it: a scaffold must be braced and tied into a permanent structure or otherwise stabilised, ties must be used within their safe working load, and proprietary system scaffolds must be erected and tied according to the manufacturer’s instructions (HSE scaffolding guidance).
The NASC’s technical committee chair put it the same way when the new TG4 user guide was launched in June 2026: ties play a critical role in ensuring the stability of scaffolding structures (NASC). In the glossary, a wall tie is the assembly of anchor, tie tube or bracket, and coupler that makes one tie point.
What do tie patterns look like in real instructions?
Each system sets its own pattern, and the cladding changes it. Three published sources show the range:
| System and source | Unclad or netted scaffold | Sheeted scaffold |
|---|---|---|
| Layher Blitz 70 steel frame, German approval Z-8.1-16.2 (2 January 2025) | 8 m staggered pattern (edge frames every 4 m) or 4 m continuous, depending on configuration | The 8 m staggered pattern is not listed for tarpaulin sheeting; those configurations use a 2 m pattern at every node |
| HAKI Universal, HAKI assembly instruction (2021) | A tie on every inner standard every 4 m of height; the lowest tie no more than about 4.8 m above ground; ties that resist forces along the facade at least on every fifth pair of standards | Number of ties increased for the wind load; a separate calculation is required |
| Jamax frame scaffold, user guide 4th edition rev. 2 (28 August 2025) | No more than 4 m vertically between ties, in one of two staggered layouts, and always a tie at the top platform level | A tie at every node, no more than 2 m vertically |
Sources: DIBt Z-8.1-16.2, Annex B section B.5.pdf), HAKI Universal assembly instruction, page 26, Jamax user guide, section 6.4.
Two details recur across manuals. The tie goes on the inner standard as close as possible to the node where ledger and standard meet; the Layher approval allows a tie level to sit at most 30 cm from the node. And the top of the scaffold is tied more densely, because the top lift has nothing above it to share the load: Layher ties every standard in the top lift unless the level below is tied. For tube and fitting scaffolds in the UK, the pattern comes from TG20:21 instead of a manufacturer’s manual. TG20:21 is a paid NASC eGuide, and each compliance sheet it produces carries an illustration and the principal criteria on the front and the detailed criteria on the back (ScaffMag, April 2021), so its tie spacings are read from the sheet for that scaffold, not from a general table. Where a scaffold falls outside TG20, HSE expects the design to state the maximum tie spacing, horizontal and vertical, and the tie duty. Our facade planning guide shows where ties sit in the overall plan.
How much force does one tie carry?
More than most people expect, and far more once the scaffold is sheeted. The Jamax guide lists the load per tie point at full load and maximum wind, to EN 12810-1:
| Scaffold height | Unclad, ties every 4 m | Netted, ties every 2 m | Sheeted, ties every 2 m |
|---|---|---|---|
| Up to 10 m | 2.0 kN into the wall | 2.53 kN | 5.05 kN |
| Up to 20 m | 2.3 kN | 2.87 kN | 5.73 kN |
| Up to 25 m | 2.43 kN | 3.04 kN | 6.07 kN |
Even with twice as many ties, each sheeted tie carries about two and a half times the force of an unclad one. HAKI gives design loads for a 24 m standard scaffold to EN 12811: 8.1 kN perpendicular and 5.5 kN parallel to the facade for ties that resist sideways forces, and 4.6 kN perpendicular for the others. The Layher approval shows how much the facade itself matters: for the basic unclad configuration in the 8 m staggered pattern, the characteristic force perpendicular to the wall is 4.7 kN in front of a partly open facade and 1.7 kN in front of a closed one, because wind passes through the openings and pushes on the scaffold from behind. These are characteristic values; the approval says to multiply them by a partial factor of 1.5 when checking the anchor and the wall.
The working capacity of the tie hardware has to match. HAKI’s tie tubes, for example, are rated from 2.5 kN for the coupler-fixed steel tube to 9 kN for the 16 mm hook version. HAKI converts design load to permitted load by dividing by 1.5, so a side-force tie designed for 8.1 kN needs hardware rated about 5.4 kN; the 2.5 kN coupler-fixed tube is not enough there.
Accessories add load in one place. The Jamax guide requires extra ties to the wall wherever brackets, a gin wheel or similar equipment are mounted, and a hoist tied to the scaffold needs its own check; see scaffold hoists.
What types of tie are there?
- Ring bolt and coupler tie. An eye bolt or ring bolt is drilled and anchored into the wall, a short tie tube passes through the eye and is coupled to the inner standard, or to both standards, close to a node. This is the standard tie on system scaffolds and the one that is proof-tested.
- Box tie. Tubes and couplers wrap around a column or pier, so the tie grips the structure without drilling. Useful on framed buildings.
- Lip tie. A hooked tube catches behind a floor slab edge or a wall, often combined with a box tie.
- Through tie. A tube passes through a window or opening and is braced against the inside of the wall.
- Reveal tie. A tube is wedged across a window opening with a screw jack and the scaffold is tied to it. It depends entirely on friction, so it is easily loosened by vibration or by the window fitter. German guidance lists friction-wedged fixings in reveals among unsuitable anchors, together with tying wire, cable ties and ropes (DGUV Information 201-011, section 4.9).
Whatever the type, it must land in sound structure. The same German guidance names snow guards, lightning conductors, downpipes and window frames as unsuitable anchor points, and reinforced concrete and load-bearing masonry as suitable ones.
How are anchors tested in the UK?
The guidance is NASC TG4:25, Anchorage Systems for Scaffolding, issued in 2025 and joined in June 2026 by a pocket user guide for the scaffolders who install and test drilled and cast-in anchors. TG4 distinguishes preliminary tests, used where it is uncertain how an anchor behaves in a base material, from proof tests on the anchors actually installed. As reported by ScaffMag, TG4:25 requires a sample to be proof-tested on each project, at least 5 % selected at random, with a minimum of 3 anchors in each separate area (ScaffMag on TG4:25).
For the test load, the anchor maker Hydrajaws, writing on the code of practice for post-installed anchors BS 8539, describes proof loads of 1.25 times the working load of each anchor, at least five preliminary tests per base material, and an escalation rule: testing doubles after one failure, doubles again after a second, and goes to every anchor after more than two (ScaffMag, 2020). Germany is stricter on the sample: DGUV 201-011 asks for 1.2 times the required tie force on at least 10 % of anchors in concrete and 30 % in other materials, never fewer than five. Keep every result with the scaffold records, so the person who inspects the scaffold can see which anchors passed.
What happens when you sheet or net the scaffold?
Sheeting turns a lattice the wind passes through into a sail. That is why every manual above changes the pattern for cladding, and why HSE says never to sheet or attach debris netting to a scaffold without informing those involved in the design. When a design is requested, the request must say whether sheeting, netting or brick guards are needed. NASC publishes separate guidance on cladding, TG27:25 Cladding of Scaffolding, covering its planning, design, installation and management.
In practice the order is: decide the cladding, get the tie pattern for that cladding, then build. A scaffold that was handed over unclad and is sheeted later by another trade is no longer the scaffold that was designed. The inspection checklist treats added sheeting as a reason to stop and re-check the ties, and the article on load classes covers the other half of the design: what the decks may carry.
What does OSHA require in the US?
US federal rules tie the requirement to the scaffold’s proportions: under 29 CFR 1926.451(c)(1), a supported scaffold taller than four times its base width must be restrained by guys, ties or braces, at the spacing the manufacturer recommends or the default the rule sets, and (f)(12) forbids wind screens unless the scaffold is secured against the forces they bring. The default spacings are set out in our guide to OSHA scaffolding requirements; they are a minimum for a bare scaffold, and a manufacturer’s sheeted pattern is usually far denser.
Who may remove or move a tie?
Only a competent scaffolder, and only with a replacement. HSE says to install ties as the scaffold is erected and remove them only in stages as it is struck (the full erection order is in how to erect scaffolding), and if a tie has to come out so that work can proceed, an equivalent tie must be provided nearby. Window replacement, rendering and new cladding all need the wall face clear, so agree in advance where ties will move to and who moves them.
In ScaFix, tie points are part of the planned 3D model and parts list, so the count can be checked against the manual before the scaffold goes up.
Planning information only, not structural approval. The tie pattern and tie forces come from the manufacturer’s instructions, TG20 or a scaffold design; anchors are tested to TG4, and in the UK the Work at Height Regulations and HSE guidance, in the US OSHA 29 CFR 1926 Subpart L, decide. A competent person must inspect the scaffold before use.
Frequently asked questions
How far apart should scaffold ties be?
On most system scaffolds 4 m vertically when unclad and 2 m when sheeted, but the exact pattern is set by the system’s instructions or a design. In the US the default maximum is 20 ft or 26 ft vertically and 30 ft horizontally.
How many scaffold ties per square metre?
None of the manuals or guidance above sets a ratio per square metre. The count follows from the vertical and horizontal spacing in the manual, the TG20 compliance sheet or the design, and it rises sharply once the scaffold is netted or sheeted.
What is the 4:1 rule for scaffolds?
Under OSHA 1926.451(c)(1), a supported scaffold taller than four times its base width must be tied, guyed or braced. The first tie goes at the 4:1 height, and the top tie no lower than that ratio from the top.
Can you tie a scaffold to a downpipe or window frame?
No. Downpipes, window frames, snow guards and lightning conductors cannot carry tie forces; anchors belong in reinforced concrete or load-bearing masonry.
How many scaffold anchors need a pull test?
Under NASC TG4:25, at least 5 % of the installed anchors, chosen at random, and never fewer than three in each separate area. Failures increase the sample.
Do I need more ties if I add debris netting?
Yes. Netting and especially sheeting raise the wind force on every tie, so the pattern must come from the instructions or design for the clad scaffold before the netting goes on.
Sources
Primary sources used for this article, with the date each was read.
- HSE: Scaffolding (construction safety topics) (read 23 October 2026)
- eCFR: 29 CFR 1926.451 General requirements (scaffolds) (read 23 October 2026)
- NASC: new TG4 user guide and poster (22 June 2026) (read 23 October 2026)
- ScaffMag: New NASC TG4 guidance targets anchor tie safety on site (read 23 October 2026)
- ScaffMag / Hydrajaws: The importance of installing and checking scaffold ties (2020) (read 23 October 2026)
- NASC TG27:25 Cladding of Scaffolding (read 23 October 2026)
- DIBt approval Z-8.1-16.2: Layher Blitz Gerüst 70 Stahl (2 January 2025).pdf) (read 23 October 2026)
- HAKI Universal assembly instruction (HAKI AB, 2021) (read 23 October 2026)
- Jamax user guide, 4th edition rev. 2 (28 August 2025) (read 23 October 2026)
- DGUV Information 201-011 (January 2023) (read 23 October 2026)