Two oak trees spaced three meters apart at the back of the garden, children asking for a swing since spring: we know the scenario. Before rushing to buy rope, it’s better to lay down some technical foundations. Installing a swing between two trees requires checking the strength of the trunks, choosing the right attachment system, and planning a safety perimeter that is often underestimated.
Choosing the trees and checking before installation
You don’t hang a swing on just any tree. The first instinct is to observe the bark and trunk at chest height. A tree with cavities, mushrooms at the base, or bark that is peeling off in patches is not a reliable candidate.
The diameter of the trunk is as important as the species. Hardwoods (oak, beech, maple) handle dynamic loads well. Young softwoods or trees with soft wood (poplar, willow) bend more and deteriorate poorly under repeated stress. A trunk with too small a diameter will not withstand the jolts of a child swinging at full speed.
Spacing is also checked. If the two trees are too close, the crossbeam will be short and the swing will lack amplitude. If they are too far apart, the beam will need to be oversized to avoid sagging in the center. The right gap is one that allows the beam to rest securely on each trunk without excessive overhang.
For those who want to delve deeper into the complete method and make a swing between two trees with a detailed guide, strap attachment techniques deserve special attention.
Strap or bolt attachment: which method for the crossbeam
This is the point that divides DIY enthusiasts the most. Two approaches coexist, and the choice depends as much on the health of the tree as on the expected load.
Ratchet straps or wide textile straps
The strap wraps around the trunk without piercing it. A protective layer (piece of rubber, old inner tube, distribution board) is placed between the strap and the bark to prevent abrasion. Protecting the bark prevents the strap from digging into the trunk over the seasons.
The advantage: no injury to the tree, easy disassembly in autumn. The downside: textile straps loosen over time and with humidity. They need to be tightened at least once per season, and the seams should be inspected before each use.
Through-bolt attachment
A galvanized bolt passes through the trunk and holds a metal support on which the beam rests. The attachment is stiffer, but it creates a wound in the living wood. On a healthy tree, healing occurs in a few years. On a weakened subject, the hole becomes an entry point for fungi.
- Use stainless steel or hot-dip galvanized bolts to avoid corrosion from sap contact
- Drill a diameter slightly smaller than the bolt so that the tightening is firm without splitting the fibers
- Never use a too-short lag screw: the penetration into the wood must be sufficient to withstand dynamic loads
Feedback varies on this point: some arborists categorically discourage drilling, while others believe that a single well-placed bolt causes less damage than a strap that rubs for years.
Safety zone around the swing between two trees
This is the blind spot of most tutorials. You install the swing, test it, the children are delighted, and no one measures the free space around.
Plan for at least two meters of clear space all around the structure is the recurring recommendation from playground manufacturers. Two meters without a wall, without a fence, without garden furniture, without another low tree. This buffer zone absorbs lateral falls and jumps at the end of the swing.
The ground matters too. Grass absorbs better than hard soil, but less than a layer of wood chips or sand. Avoid slabs, fine gravel (which can be thrown), and concrete. A shock-absorbing surface under the swing reduces the severity of falls, especially for children under six years old.
Neighborhood rules and prior declaration for a garden swing
Few DIY guides mention this, and it’s an oversight that can be costly. The French Civil Code does not set any specific minimum distance for a swing from a fence. However, judges can sanction abnormal disturbances to the neighborhood: repeated noise, impacts on the shared fence, visual nuisance.
In practice, avoid installing the swing less than two meters from the property line. If the swing set is massive or covered (with a protective roof, for example), the local urban planning regulations may require a prior declaration. Before pouring concrete or erecting a large structure, a visit to the town hall clarifies the situation.
Mounting the seat and choosing the rope or chains
The crossbeam is in place, the attachments are solid: the seat remains. Two options dominate for suspension.
- Polypropylene braided rope resists UV and moisture but heats up when in contact with hands in the summer. A comfortable diameter for children’s hands is preferred
- Galvanized chains offer superior durability and do not loosen. The risk: fingers getting caught between the links. Plastic sleeves on the chains solve the problem
- Natural hemp rope has a pleasant appearance but deteriorates quickly outdoors. It is suitable for occasional use, not for a permanent installation
For the wooden seat, choose a sufficiently thick board, sanded on the edges, treated for outdoor use. The holes for the rope should be drilled at a good distance from the edges to prevent the wood from splitting under tension.
Last often overlooked point: test the swing yourself before allowing the children to get on. An adult weighs more, which allows checking that the beam does not sag abnormally and that the attachments hold under a load greater than expected. If everything remains stable after a few minutes of vigorous swinging, the installation is ready.