Replacing the entire base of a roof versus replacing parts of the roof
If a 4 foot by 16 foot patio roof is being re-roofed (repair of roof all the way down to base, inspection, repair of sub-floor, installation of bitumen, installation of flashings, etc) and it turns out the entire floor base needs to be replaced (versus small parts being replaced), would that lead to "redefining" the original scope of the work? If so, how much larger of a job would this be?
We've had a revised estimate submitted and want a fair outcome for both the contractor and us. We have a job underway mid-stream. We originally got 3 bids (checked, references) and took the most expensive, knowing we wanted it done right and the contractors recommendations.
If it were a new work scope, does $1,000, $2,000, $4,000, $6,000, $8,000, or $10,000 sound like a better very high level ball park to be in (we have three 4 by 16 foot patios and the entire cost of this job's already been agreed to)?
Just want to look at this from both our sides and see what reasonable range would be, if it's an enhanced job? My impression going in was replacing the whole base would be more materials and not an enhanced/new scope of work, curious about any thoughts? Thank you,