Basic Information

When building a treehouse a security system is required to move between the trees in order to knot beams and nail the boards. The security system needs to contain a horizontal security line of calculated and tested strength - sufficient to hold three or more people.

There are different systems possible such as ratchet straps or steel cable systems. A system should be checked for strength, length of fall and impact when falling before use. The most commonly used system by participating organisations is the use of ratchet straps without any wear with a lashing capacity of 5000kg.

Do not simply copy such a system but check this with your permits and insurance.

Security Line

Further Information

Details about the Security Line System

The choice of which security system should be based on the durability, costs, strength, length of fall and ease of installation. Of these all but the costs influence (the uncertainty of) the strength of the system.

A system that has a short durability, for example, creates more doubt in the strength of the material. This can be countered by replacing the material within short intervals. This will, however, increase the costs.

The strength of a system should be adequate and in line with your insurance guidelines. A standard industrial safety factor is 7. It should be noted that with ratchet straps it is explicitly said not to use these for safety securing. If your insurance guidelines are strict, as is the case in the Netherlands, steel cable systems are therefore a preferable option.

The costs over time for the two mentioned systems are similar; the costs for steel cables are higher initially but the replacement costs are much lower, since the durability is better for steel cables compared to ratchet straps.

The length of the fall in the system should be limited and accounted for in the strength calculation. It should also be taken into account that the shock on the person should be not exceeding the maximum load a human body can withstand.

The ease of installation is important for two reasons. Firstly, a user-friendly system is preferable for practical reasons and ease of use. Secondly, it improves safety since an easy to use system has a much higher chance of being constructed according to the necessary guidelines. An installation using the necessary guidelines is paramount for the safety of the system.

Security Line Spreadsheet


CVJM-Akademie gGmbH
Institut für Erlebnispädagogik
Im Dru­sel­tal 8
34131 Kassel

Tele­fon: + 49 (0) 561 30 87–506
Fax: +49 (0) 561 30 87–501

Funded by Erasmus+ "Youth in Action"

The website and the content was developed in the project "Treehouse Camps - a Method to Strengthen Key Competences and Integration in Youth Work".

Project duration: September 2018 - August 2021