A deck is typically attached to a house and accessed via the back door. Decks are usually constructed from wood or composite materials. A terrace, on the other hand, is a raised platform that can be attached to or detached from the house and is typically made from a hard-paved material, such as paving stones. Terraces can be built on the ground or on the roof of a home.

Before installing a deck, you must build a base for the deck to rest upon, often made of compacted soil or gravel. While gravel is an optional material, it helps with drainage. Some contractors also recommend installing a weed control membrane, which helps provide a solid foundation for the frame. In the case of an elevated deck, a pro will often lay down a concrete slab as a foundation. 

Whether you need a permit depends on the deck design and local regulations. Most areas mandate a building permit if the deck is over a specific height or if it's attached to a pre-existing structure. Shorter, freestanding decks may not require a permit, but you should check with local zoning ordinances and your homeowners association for specifics.

Yes, pressure washing a wood deck can be a good idea as it effectively lifts ingrained dirt, mold, and mildew, improving the deck's appearance and longevity. However, it must be done carefully, as it's easy to damage the wood, especially softwoods. To pressure wash safely, use a lower pressure setting and a wide, 40-degree fan pattern nozzle (often white). Keep the nozzle at least a foot away from the wood surface and maintain constant motion, avoiding hovering in one spot to prevent gouging.