At its most basic, a deck is an extension of your house. You open your door, walk outside and there you are in what feels like an outdoor room.

But let’s be real: Some decks have become much more than that — a manifestation of the homeowner’s aesthetic taste, desire and ego laid out over vast expanses of wood (or products meant to look like wood), stone and lighting. Some decks could be mistaken for helipads if helipads had pergolas and open-air kitchens.

Any deck that aspires to be more than something that leads into your yard does not come cheap. Even the most basic wooden deck — one now seen as passé — can cost about $10,000. At the upper ends, decks can cost well beyond $100,000.

Pete Ciaraldi, a deck contractor outside Boston, said he recently installed a multilevel, well-lighted deck that cost $148,000 in Wilbraham, Mass., a modest suburb of Springfield. What surprised him wasn’t the price of the deck — he puts in lots of expensive decks — but that the house it is attached to is worth only $485,000.