A mix up in the Boro defence after 14 minutes saw the loose ball picked up by an East Thurrock forward but his shot hit the top of the crossbar and over before Robbie Norris went close at the other end shortly after.
On 23 minutes Romford went ahead when a pinpoint long ball by Jack Barry found Miguel Lopes Dematos who coolly slotted home under the onrushing keeper for a half time lead.
A good save by Davis Boateng in the Romford goal was followed by another East Thurrock chance blazed over.
After 74 minutes Nick Reynolds was unlucky with a shot that he bent a little over the bar, but Boro went further ahead five minutes from time when a lovely control and turn from Dematos set up an attack down the left that ended with David Ottley heading in a cross from Ryan Imbert.
ROMFORD: Davis Boateng, David Ottley, Jamie Dicks, Jack Barry (c), George Woodward (Yusuf Bello 60), Archie Barnes (James Ishmail 60), Taj Hussain (Abs Seymour 60), Jordan Thomas (Nick Reynolds 60), Miguel Lopes Dematos, Robbie Norris, Hugo De Jesus (Ryan Imbert 60)
UNUSED SUBS: Aaron Omand, Matt Toms
SCORERS: Miguel Lopes Dematos 23, David Ottley 85
MATCH REPORT BY PHIL REDWIN