I just had a new vinyl sliding glass door installed. The door does not sit tight against the extension jamb on the top right but sits tight in other areas. There is a gap that the installer used foam to fill in, and not very well. What would be the cause of this type of poor installation. Would it be because the door is warped or the frame is out of square or just poor work? The door that he replaced sat tight and square. There is also a gap at the top of the door.
Why? If you asked the installer why there is a gap, then I am certain you would get a reason like: 'The original door was crooked' or 'The trim is wrong' or something else that puts the blame on somewhere else.
The reasons the installer would quickly provide may have a measure of truth to them. The details of a house are never perfectly straight and the trim was cut to conceal error of the original door install. Here we have a new door install and it does not fit the old trim, or the old hole, or something is somehow different or has changed over time.
The Truth: You can pay someone to do anything, but you can't pay them to care. Caring is in the person or it is not.
That's the bottom line fact. Even if something unusual happened, existed in the new door, or previously existed, the installer should have noticed the gap and spoke clearly with you about it and arrived at an acceptable solution before calling the job complete.
What to do: Monkey with it yourself, filling the gap with caulking, or adding small quarter-round or something you like better, or call another contractor.
What NOT to do: Don't complain to the guy that put the door in. He noticed the gap. He walked away from it. He didn't want to deal with it then. And if he didn't say anything, then he doesn't want to deal with it now.
What does it look like on the outside (please include a picture)?
It's possible that the new door has a narrower casing than the old door, and it is installed against the trim outside, leaving a gap at the trim inside. If this is the case, the installer chose wisely to seal the outside and leave the inside for later finishing (by you or someone else). Of course, the inside should have been taken care of, unless agreed otherwise.
To resolve this, remove the existing brown inside trim (the one with a rectangular profile and a nail showing in the picture), and see if it can be moved so that it is flush against the door but still cover the gap.
Otherwise, simply buy some more trim (door-stop moulding, quarter round), finish it with a matching brown varnish, and install it over the gap.
Or buy wider door-stop moulding and replace the existing one.
Depending on your choice of the above you may have to trim away the spray foam with a utility knife.
If you are concerned about the door being level, it's best to check with a 4ft level first, and not go by the trims and gaps: check the horizontal and the tilt.
It's not uncommon for the trim or even the house frame to be off. Also check the existing trim for tilt and plumb. Let us know (take a picture of the level) and I'll edit my answer if needed.
To check if the door itself is square, use a cabinet makers square, and that must be fixed by the installer as it affects the door warranty.
Regardless, the foam must stop all drafts and airflow, and provide a vapour barrier. These are not the job of the trim. So this may require a separate fix. You can fill the gap with more foam, but since that's messy (and difficult if already partially filled) you can also simply cover it with "technical tape" a.k.a "sheathing tape" or caulking before the trim goes on.