Probably will help if you clarify who owns what and type of builder.

Who owns the lot?

Custom home plan or builder's plan?

Small builder who does a few houses per year or large tract builder?

Fixed price or Cost Plus contract?

We own the lot. Mid size builder, custom home plan. Cost plus.

Do you have an architect involved in this project?

Meet with the builder face to face as soon as possible. Meeting in person is very important for disagreements, as you don't want any misunderstandings.

Hopefully it isn't a sign of poor management and/or low quality subs, but you should have a gut feeling about this if you did your research and picked the right builder.

We rented a mile away while building. I can't imagine not being able to walk through at least once a day for a custom home. I designed all the details/finishes in the house, so I was the one person who knew all the details. I also speak a couple of languages, so could talk to the subs directly with nothing lost in translation! I stopped in every morning to answer any questions from the subs working that day and then stopped in again after they left to see what was done. Any errors were caught the same day and usually fixed by my builder the next day. I basically "worked" as the designer for our build ... our builder was great and it was a good partnership.

Photos would help clarify a lot. Jobsite & plans. 1% garage floor slope is perfect.

Focus on gathering information first. A casual onsite walk thru with the builder at this point.

That might be weekday business hours.

An ask about the front porch might help. Patio dimensions vs footings. Is the concrete to wood intersection flashed or do they have a water pathway strategy?

1% slope can be adequate if it's a good straight pour and it doesn't settle. You have to broom/squeegee to the doors anyway in snow country. No to concrete on wood. That's a code violation and it will eventually rot.

There have been times when I have visited my project's construction site to observe the work in progress. I have seen work that is not completed and it has looked questionable to me. So I ask about it. Most of the time it looks questionable because it is not completed and there is nothing wrong. Rarely is there something actually wrong.

On one particular project of mine I observed a garage wall that had two door openings in it that lead into the house. One door opening had the header located just above the door opening, and the other door opening had the header located just under the top plate. Both acceptable ways to frame an opening. When I inquired about the difference, the builder went into a long explanation that included uneven snow loads. wood species, house color, sun angle, airspeed velocity of an unladen sparrow, . . . until he could no longer keep a straight face, and confessed it was two rough carpenters that properly framed the openings two different ways.

1.) A 1% slope is 1/8" per foot. That is adequate, maybe even a tiny bit too steep. So if you have a 24' deep garage, sloping towards the overhead door, that would be a 3" rise. Also, realize that 1/4" per foot is for your plumbing pipes, and when you have 3"+ size of pipe, you can reduce pitch to 1/8" per foot and still move effluent along. Water will move on your slab with less than 1/8" per foot, you don't need to have a waterfall, just direct the water where you want it.

2.) A porch concrete slab is typically always against the rim board/joist (wood framing). If it is not, then you will need a step or 2 or 3 right out your door, but there are egress restrictions on steps, landings, and heights when exiting the front door. So typically, the porch concrete slab is set no more than 7 3/4" below the threshold height of the front door, putting it against wood. What is of concern is that a waterproof membrane is applied to the wood framing that the concrete will touch. As far as the porch being built larger than the plan shows, more info would be needed, but a simple question to the builder should answer that. If you are worried about snow depth, a porch is usually covered, and, if it was a critical issue, then it should have been addressed during design for the entire house, not just the porch.

3onthetree, you've never poured concrete, have you? There are ways to detail flush entrances without relying on flashing that sheds water to nowhere.

@Seabornman Huh? Yes, you want my resume? Maybe look at some section details of porches so you understand the heights and how the framing sits on a foundation wall. And the OP does not say it's a flush entry, but either way, waterproof membrane over the wood, period. Waterproof membrane is not flashing, the membrane protects the wood from moisture. Flashing is what would be directing water away from something, you know.

3onthetree, I'm not hiring right now, so I don't need your resume. Cold concrete up against wood, waterproofing or not, is a recipe for condensation and rot.

Monday morning fits @Seabornman? Wood is against concrete in many acceptable scenarios. No code provision preventing that. 90% of the users on this website can walk out on their front concrete porch and see it is above the floor framing.

"90% of the users on this website can walk out on their front concrete porch and see it is above the floor framing."

Maybe in Arizona. But where I live it rains and is humid and, without a lot of attention to detail, the framing will rot out. Maybe not within the contractor's warranty period, but it will rot out. It's fairly easy to do it right.