Insulating Hot water pipe

[Deleted 206958]

Hello,
I would like to insulate hot water pipe behind some boxing that was done many years ago. Any advice as to how i will go about it. I have already insulated in areas i can reach.

 

[mfarrow]

Fill the void with expanding foam.

 

[Charnwood]

How long is a piece of string.

Some pictures might be useful. Until then only you know how accessible/inaccessible the area is.