Are timber frame swings strong enough for adults?

You can probably guess what the answer to this question is going to be:

It depends!

There are no specific design standards for adults as there are for children (up to 14 years old), because adults are expected to be able to think for themselves and weigh up the risks of what they are doing.

Obviously, if you are providing a public playground for adults you are subject to the whole gamut of health and safety legislation. But if you want to make a swing in your back garden on which you can gently oscillate away the pressures of the day, then common sense, and some understanding of the risks involved will help to ensure that your dreams (and yourself) don’t come crashing down.

What is the weight loading for a timber swing frame?

You may be surprised to learn that simply hanging weights from a swing to test its loading ability does not tell the whole story. It can in fact be frighteningly misleading. The loading on a swing when in use is dynamic, not static. Suppose you are swinging from 30° back to 30° forward. At each point of that arc, the loading on the frame is changing, both in direction and intensity. And if you swing to 60° (or go mad and make it 90°) the figures will increase dramatically.

You therefore have several factors at work in your efforts to support this dynamic loading: the size of timber used in the leg assemblies; the size of timber used in the top bar; and how they are fixed together. Also how it is secured to the ground.

And that’s not all. The length of the top bar, and the positioning of the suspension points along its length also play a part. If all the weight is suspended from the centre point of the bar it will support less than if the weight is divided in two and suspended close to the leg assemblies at each side.

So the answer is: better to over-specify. You won’t regret have a frame that’s too strong, but you might regret it if it is not strong enough.

Can I make a timber swing for adults?

Let’s start with what not to use when making a swing suitable for adults.

Many swing kits use 70mm diameter timber for the legs. While this may be acceptable for small children it is not advisable for teenagers and definitely not strong enough for adults.

100mm timber legs are a far better option, both for longevity and strength, and, depending on other factors, would be better able to cope with light adult usage.

The optimum timber size for adult usage would be 150mm. When concreted into the ground, either directly or by the use of galvanised steel leg supports, these timbers would cope with responsible adult usage.

Then again, how heavy is an ‘adult?’ No-one can give you an exact loading figure for your frame, and no-one can tell you how much a ‘standard adult weighs!’ We don’t come in standard sizes do we!

What is the best timber size for a swing top bar?

Again, this depends on the length of the top bar, where the suspension points are, and the type of use proposed. For a single, double or triple swing, a 100mm top bar is adequate for children’s use. You can get an idea of weight loading by bearing in mind that a popular manufacturer of domestic swing seats allows a weight limit of up to 50kg per child. That’s about 7st 12lb. To increase that would require the use of commercial type swing seats with chains rather than ropes. A heavy duty top bar for these would be 120mm timber, again, for garden use only. The optimum timber size (recommended for adult use) would be 150mm.

Can I make a double swing for adults?

It is more fun to have two or even three swing seats on the same top bar, but be careful if you want to cater for older teenagers or adults. The watchword is: increase the timber size as you go longer. And to go ultra secure, use an extra pair of legs to support the top bar between each swing seat.

What swing seats are best for adults?

The best swing seat would be rubber with metal inserts for strength, and definitely go for chain suspension, not rope. And go large… you don’t want anyone getting stuck between the chains!