Pros, I apologize for the long story, but I'm trying to give you all the facts and really want input on this issue.

As part of my stairwell remodel, I contracted to have a ventilating skylight put in at the very top for light and to expel the trapped heat.
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In addition to installing the skylight (wrapping, leak barrier, shingle repair), the contract details:
• All rough framing from roof deck to ceiling
• No interior finishes or electrical
• "Skylight tunnel will be "cased" with plywood from attic side to protect interior from attic infiltration until homeowner finishes interior"
• Estimate time of completion from start of work is: 1 day
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Monday: The assigned worker showed up a few hours late. He stayed two hours, took a lot of measurements and left saying it might rain. He brought a smaller skylight than stated in the contract: VSE 104 (approx. 22"x38") due to concerns about the nearby roof valley. Disappointing, but better than a future leak. The contract states they will either install a "VSE 106 (22"x46") or a VSE 606 (44"x46") skylight.
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Tuesday: Only an hour late, but he brought a helper. The helper cut the hole in the ceiling (see pic). The worker the framed the shaft, but didn't case it with plywood.
I asked, he said he didn't know anything about that. I showed him the statement in his copy of the contract. He sealed the ceiling hole with the cardboard box (see pic). They left early, saying it might rain.
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Wednesday: Stayed a full day - cut the hole in the roof and installed the skylight ... all dried in. The skylight is not centered, but pushed up and left ... more concerns with the roof valley. Wish the boss and the carpenter @ the pre-construction meeting would have noticed that ... bummer.
I hooked up the electrical and tested the skylight ... it works ... Yay
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Friday: He came back to case the framing with plywood (see pics) and was ready to leave.
I pointed out that the attic was still open to the house, since the plywood was cut several inches short all the way around. I asked how he was going to seal it; maybe, more plywood or trim it out? He said that he didn't have any more plywood and he had to go (it was noon). Also, when I do the interior finishing it'll be fine. I told him that might not be soon, since I have to finish other parts of my project before getting the plaster crew in here.
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Then he called the office and wanted me to pay the 2nd half of the labor and for the VELUX skylight. They wanted to charge me more for the smaller skylight than the VSE 106 in the contract. So, I told him I'd contact his office & we'd work out our discrepancies. It was fine by him and he's outta here.
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I sent an email to my contractor POC (the guy who came out when we wrote the contract) with these pictures. The worker called me back a few hours later asking why I didn't say anything when he was here (really?) and what he can do to make me happy. I told him that all I want is for the skylight tunnel to be cased as specified in the contract.
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He said it was a miscommunication. Had he known I didn't want any air from the attic to get into the house, he would have framed it differently. He said he can't come back today and asked again what he can do to make me happy. So I repeated that for me to be satisfied, the work had to be completed as stated in the contract. No go, but he made an appointment to come back, which had to be the next time I was home (two weeks later).
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That Friday evening we picked up relatives from the airport. The next morning we hauled them and the locals to a rented lake house for our annual family vacation. Guess who spent all available "spare time" hanging from a ladder? The cardboard had gaps, so I pulled it down (only held by a few tacks). I sealed the framing from the inside with plastic and from the attic with all the insulation I could stuff into the gaps.
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So my question is this: What does "protect interior from attic infiltration" mean? I took it to mean that air from the attic would not leak into the interior of the home. I didn't want the heat from the attic in the house, nor did I want to cool the attic while we were gone. The worker called it a miscommunication, so I may not understand the term "attic infiltration". Please educate me ... I have to deal with this guy again real soon.