Under pressure from the off, Slough never got into the game and found themselves three down at half time.
Slough improved slightly in the second half, but were still by far the lesser of the two teams on the pitch as Billericay ran riot with a six goal haul.
Matt Murphy was guilty of missing two good chances for the Rebels, and Seedel also fired a half-chance wide.
Armstrong scored first for the visitors, slotted home after Parkin had made a good save.
Ten minutes later it was 2-0 after Michael Murphy was dispossesed, and Wareham received a pass to score.
A minute later Matt Murphy fired a good chance straight at goalkeeper Mel Capleton when in lots of space
Instead, after 37 minutes Dormer was unmarked to meet a cross and make it three for the Essex side.
Slough began to show frustration, with Saulsbury cautioned for unnecessarily kicking the ball away right in front of the referee.
Minutes into the second half, Matt Murphy headed wide from close range, and Slough were punished further on 53 minutes when a good passing move opened the Slough defence for Armstrong's second.
He added two more in the closing stages with the Rebels rearguard looking shell-shocked.
Slough had further chances through Murphy and Seedel, but the game petered out and Eddie Denton was left to reflect on a bad day at the office.
Billericay Town Line up
Capleton, McSweeney, Price, Sappleton, Trott (c), Dormer (Oxby), Game, Hunter (Cousins), Wareham, Armstrong, Gallacher. Subs not used: Elder, Kerrigan, Forbes.