Leicester Tigers had four men in the England XV after prop Dan Cole was given a late call-up to join Ollie Dodge, Tom Youngs and Alex Shaw in action.
Dave Doherty kicked England into the lead and the visitors looked to extend the advantage only to be called back when Shaw's offload was ruled forward.
Ireland stepped up a gear in torrential rain and wing Shane Monahan grabbed the only try of the game. Ian Keatley converted.
Doherty kicked a second penalty to bring England back to within a point but Keatley made amends for two earlier misses as he bagged two penalties for Ireland to keep them on course for a Grand Slam.
England coach Redman said: "The Irish played the conditions well. We got bogged down in certain areas of the field. I thought we made a few good line breaks in the first half where a bit of patience would have brought a better result. But we coughed up too much ball in key areas.
"What we have to do now is make sure that the lessons we learn from tonight we take forward into the next matches."
Ireland Under-20s:
F Jones (Seapoint/Leinster); S Monahan (Dublin Univ/Leinster), D Cave (Belfast Harlequins/Ulster), A Wynne (Buccaneers/Connacht), K Earls (Thomond/Munster); I Keatley (UCD/Leinster), P O'Donohoe (UCD/Leinster), Cian Healy (Clontarf/Leinster), R Sweeney (St. Mary's College/Leinster), J Hagan (Greystones/Leinster), C McInerney (UCD/Leinster), A Browne (Galwegians/Connacht), T Anderson (Dungannon/Ulster), D Pollock (capt, QUB/Ulster), S O'Brien (UCD/Leinster). Reps: T O'Donnell (UL Bohemians/Munster) for O'Brien 32, R Murphy (Lansdowne/Leinster) for Hagan 78, N Keogh (UCC/Munster) for McInerney 78. Not used: G Slattery (Young Munster/Munster), D Drake (Ballymena/Ulster), N O'Connor (Belfast Harlequins/Ulster), K Tonetti (Blackrock College/Leinster).
England Under-20s:
D Doherty (London Wasps); O Dodge (Leicester Tigers), T Youngs (Leicester Tigers), A Powell (Saracens), S Kuadey (Sale Sharks); S Jewell (NEC Harlequins), D Care (NEC Harlequins, capt); C Beech (Northampton Saints), M Mullan (Worcester Warriors), D Cole (Leicester Tigers), D Attwood (Bristol Rugby), P Hoy (Northampton Saints), A Shaw (Leicester Tigers), C Pennycook (Bristol Rugby), D Tait (Sale Sharks). Replacements: M Cox (Worcester Warriors) for Attwood 40, F Neale (Saracens) for Jewell 40, H Ellis (London Wasps) for Tait 48, J Turner-Hall (NEC Harlequins) for Neale 48, T Standfield (London Irish) for Mullan 73, Mullan for Cole 80. Not used: T Mercey (Saracens), R Bolt (Exeter Chiefs).