Please avoid weedkillers. They are highly poisonous and can get into the water table.
I have problems with weeds growing in between my paving slabs and find that pouring boiling water on them, and then adding salt, (as cheap as you can find), is very effective.
The reason I asked the question was because we are having a new fence fitted and the old fence is covered in ivy. To dig out the root I am unable to do due to my health and age, hence the question for something I can put on the root to kill it.
JK: I agree. NO weedkiller!
IFF only people would think through what happens to any liquid when poured on to the ground. It, and all the chemicals in the solution, have an often-negative, cumulative effect on our one-and-only environment.
As we can see with fossil-fuelled stinkers, the pollution in the atmosphere cannot be 'turned off'.
We have to live with it all.
BJS, my neighbour has just had the fence between our gardens replaced. As part of the prep work, the fence blokes dug out the ivy roots and back filled the holes. It might be worth asking about if you can afford the extra cost.