3. A good pressure washer
You need something that's rated over 1500 PSI, with 1800 to a maximum of 3200 PSI being ideal, the more pressure you have, the better the foaming and cleaning power will be. Water flow is also important, so make sure your machine has at least 7 to 8 litres per minute flow too. A hose that's 8 to 10 metres long is handy so you dont have to carry the machine around as you apply the foam. Attach the gun/Cannon to the machine with the right adapter and you’re ready to foam.
We’ve used a Gerni brand "125 Classic" pressure washer that’s rated at 1800 PSI in our videos and images here.