What you see is not what...

After an epiphany a man thought of building his own house. He studied 100s of houses. Single family homes, Condominiums, Palatial homes and what not. He took notes of anything and everything he could see in a house. How the kitchen should be, how the living area should be, bedrooms, study. After months and months of research he started to build his own. He bought a land, put bricks on top of each other for walls. He carefully put the roof on. The most beautiful entrance he could afford. Just as he finished building it, the house collapsed. Alas! He never had seen a foundation.