Yes I know it's a brand new house, what could possibly go wrong? Get an impartial professional opinion, I cannot stress this enough.
Home warranties and builder punch lists are frankly, ok, but too late when it comes to making sure you have acquired a good quality product. House builders do not like their customers to wander around the job site, some even prohibit the practice entirely and generally it's not because they are hiding something, it's because of their liability if you get hurt wandering around, they also don't want you directing the tradespeople to do different things than are called for in the contract.
A professional inspection is worth the money, especially If you cannot identify proper backing material for the shower stall, which way a joist hanger is to be installed or why concrete walls should not be honeycombed. An inspection is a quality control measure on your part and should be stipulated in the offer to purchase. There are several critical times in house construction:
1) Pre back fill: this lets the inspector examine the waterproof membrane, drainage tiles, the connections to the sump outlet and that gravel is present where it is supposed to be.
2) Framing: this is a very important step as any defects found at the framing stage can be fixed easily.
3) Pre-drywall: This step lets the inspector check the rough in electrical, the rough in plumbing and insulation, it is also the step that allows any last minute changes you want to be negotiated and incorporated into the building.
4) Punch list or pre final occupancy: Normally as a home owner this is when you will be invited in to check for deficiencies. Most owners are concerned with cabinets, flooring, doors and basically the stuff you can see. The inspector is more concerned with the quality of the installation and much less so with the actual choice of materials used. You may have a beautiful tile job in your roman bathtub if the tile is installed over ordinary drywall and not cement board, it's going to be a head ache later on.
Builders aren't trying to rip you off, but it's still your money and your house. Making sure your investment is protected is a good idea. It doesn't cost a lot, maybe $2,000.00 for the four inspections listed, but it could save you thousands of dollars over the life of the home.
Simply put, all houses have defects, drywall screws will pop, floors will squeak, hand rails will loosen, all very normal and if attended to in a timely fashion not a big deal. What is a big deal however is the quality of the work people are doing.
Home inspection is NOT a trade, we aren't carpenters or plumbers or electricians and a good inspector will not hold himself out to be, even if he is. An inspection is a systematic examination of the property to comparable and consistent construction standards. Building codes are the bare minimum and while few homes are not up to code, reliance on the code compliance inspector is not enough to ensure you get a good product. Home inspection is a quality control activity and you, as the buyer of the property, have the right to ensure you are getting the best quality job.
Horror stories abound about bad construction projects, and with some empathy for the builder, it's tough to assemble and keep the best workers in the industry, mostly because they are already busy because they are the best.
Building material itself is seldom an issue so long as it is used the way it was designed.
Your new house is a big and very personal purchase, no new house is perfect and emotion tends to magnify the scale of issues you can see. The home inspector will ensure that the fundamentals are as they should be providing you with some assurance that you have a good home for your family.