Having a gap between a structural header and a window casing (or door) is actually a desirable thing, It means any sag in the header will not immediately affect the window, The trim on the inside should easily cover the gap. You did install flashing on the outside, right? The siding will cover that.

When we purchased our house the basement was carpeted and the owners said they had a fan on because the carpet was damp as they had shampooed it. We didn’t think much about it until we purchased the house and at certain times of the day and night there would be this stench. We ended up ripping out all the ceiling and wall drywall and found that the Septic O Pipe was leaking that runs the width of the house. So every time a toilet was flushed it was dripping . We changed the pipe and now it’s gone. We also had a really bad smell in one closet in the basement, we pulled that apart and didn’t find anything , then we ended up pulling the landing off the staircase and there was a cavity where one of the previous owners had put a new landing over an old landing, there had to have been 100 dead mice in the cavity, it was so gross my husband almost passed out when he pulled it apart. Now we have no mice or gross smells. It’s really a buyer beware on some things, this stench was probably there for many years and the owners didn’t know what it was so they just lived with it. Never know what behind drywall.

Mightyanvil, Thank you so much for your response. The smell you describe is pretty right on, and it is definitely coming from the attic. We have gable end vents, 6 roof vents, but only 3 soffit vents, and they are all in one small spot. Our house has no overhangs except in our patio area and that is where the one and only soffit is. The smell comes down through the attic trap door. How can I fix this? any ideas? My husband wants to use a sealer around the trap door, he thinks that will stop the smell from coming down into our living area. I want to make another insulation blanket to lay over the trap door in the attic. We had one but the guys who did the insulation used it to add to the insulation when they were up there. I thought the blanket worked great. My concern is why are we smelling wet insulation? We have no roof leaks. When I look up there I do not see condensation. Do I need to put a fan up there? How could I do that safely? Thanks for your help.

pander, You are absolutely correct. A professional door installer would make sure the installation of the new door is both level and plumb, regardless of the out of square opening. And remember the manurfacturers warranty becomes void when the unit is improperly installed. If you've already paid for the job, then its' a matter of whether or not the dealer you purchased from will stand behind his installers. You definitely have a good reason to expect a proper installation. Thats what you paid for! Good Luck All the best, The PorchGuy