Firstly determine whether a root barrier is necessary. There is really only one bamboo we grow which we would absolutely recommend a root barrier and that is the fast and furious Arrow Bamboo.
The other 'Mid bamboo' will never require containment by root barrier as they have very little spread.
Our 'Tall bamboo' will only need a barrier if you are planting right up against a fence or a shed etc or next to decking or a patio If you can leave a minimum gap of 40cm you will have room to prune any unwanted spread. And pruning really is straight forward, it's generally a once a year job in early summer, check if there is unwanted spread and if so chop it off with secateurs or a spade.
Bamboo roots will not cause problems against brickwork or concrete, so if you are planting up against a wall a root barrier won't be necessary.
It can be hard to picture what root barrier actually is, here are some images to help.
Root barrier is made from heavy duty HDPE plastic, supplied on a roll, it is 60cm wide and 2mm thick.
Here you can see the top of the root barrier, once installed. These images show the barrier raised quite high above ground level. In the UK just slightly above ground level is sufficient.
To install the root barrier,
Find someone young and energetic to dig the trench!