Brad Ling put Glen Golby’s side ahead on 30 minutes when his cross deceived Sam Roach in goal before floating into the net.
Forward James Peagram then doubled the lead for Barking on 42 minutes to cap a fine first-half for the hosts.
John Bricknell, who had a spell with ‘Side a couple of seasons ago, made it 3-0 from the spot in second-half stoppage time for Barking’s third.
There was still time left though for ‘Side to grab a consolation through new signing Ryan Bonju, who grabbed his first goal for the club.
'Side: Sam Roach, Jak Mochalski, Jimmy Nottage, Danny Blake, Maxwell Amoako, Connor Mitchell (Fionn Glancy), Michael Ademiluyi, Jason Ajoodha (Ryan Bonju), Luke With, David Laird, Jason Fontaine.
Subs not used: George Lutaaya, Marvin Birch, Kobie Ambrose