At lunch, England were 427 for five, with Root 185 not out and the fit-again Ben Stokes unbeaten on six.
Root's Test-best 200 not out against Sri Lanka at Lord's two years ago remains his lone double century at this level.
But it was nightwatchman Woakes who did most to frustrate Pakistan in Saturday's first session with a boundary-laden 58.
The Warwickshire all-rounder was the dominant partner in a fifth-wicket stand of 103 with Root.
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The two senior batsmen had shored up an otherwise fallible top order by playing commendably straight.
But although sent in as a nightwatchman, Warwickshire all-rounder Woakes is no mug with the bat.
Two not out overnight, Woakes -- who has scored nine first-class hundreds -- was soon demonstrating a fundamentally orthodox batting technique.
When Rahat Ali, one of Pakistan's trio of left-arm quicks along with Mohammad Amir and Wahab Riaz, dropped short, he was cut for four by Woakes.
There was a brief hold-up when Woakes was struck on the right arm by Rahat.
But when Amir, who appeared to be struggling with a niggling injury, dropped short outside off stump, Woakes uppercut him for six high over third man.
Meanwhile a single off Rahat saw Root to 150 in 269 balls including 18 fours.
The Yorkshireman had batted for six hours without giving a chance on Friday but on 155 he had a reprieve when an outside edge off leg-spinner Yasir Shah just carried to first slip.
Woakes's 104-ball innings, which included eight fours and a six, ended when he chipped a return catch straight back to Shah to leave England 414 for five.
That gave Shah then-innings figures of one for 139 in 38.4 overs -- a marked contrast to his man-of-the-match return of 10 for 141 during Pakistan's 75-run win in the first Test at Lord's last week.