You can build an outdoor kitchen on a deck, but you should choose composite decking since it's more heat-resistant. Metal deck materials like steel and aluminum are also good choices because they're less flammable than wood. You should also consider the weight of the kitchen—make sure your deck can support it and any appliances you plan to use. You should consult a structural engineer to confirm exactly how much weight your deck can safely support when building an outdoor kitchen. 

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. 

Ideally, a gate should be able to swing both in and out. However, if it can only open in one direction, it is generally best for it to swing inward. This is often the safest option, especially for deck gates near steps, as you'll want the gate to swing away from the stairs. An inward swing also prevents the gate from opening into a public space, like a sidewalk, and can be more convenient when carrying heavy items like a wheelbarrow into a garden.

There are exceptions, however. The layout of your property may require a different approach. For example, if your property is on a slope, the gate may not be able to swing inward. You should also ensure the gate can open fully without colliding with any objects or blocking access to other areas. For a backyard garden gate where public access isn't a concern, the direction it swings is largely a matter of personal preference. Finally, always check your local building codes, as they may have specific requirements for which way a gate must swing.

While experienced DIYers may take on the challenge, hiring a licensed professional is often the best route, especially for larger or elevated structures. A local deck contractor is typically the best pro for the job, as they have specialized experience and are knowledgeable about local building codes, ensuring your deck is built safely and designed to last. Other professionals who can build a deck include general contractors and carpenters, who may be more readily available in some regions.