"Above code" means that the house is beyond the requirements set by your state and local governments. It means that the house is more safe and has more features than required. He's trying to sell you on the idea that this house isn't a basic model, but something special.

"Code" in this context means the rules and regulations for building a house or a building. So something "meets code" if the builder followed all of the rules. For example, say there's a rule that water pipes have to be a half a centimeter thick. If you do that, you've done what the code says. If your pipes are all 1 cm thick, then you are way above code (because you are very safe). If your pipes are thin, then you'd be below code.