Ultimately, overapplication of stain can compromise the deck's appearance, durability, and longevity. It may result in an uneven finish, with excess stain pooling, dripping, or drying into thick patches. It can also obscure the wood's natural grain and texture, detracting from the desired aesthetic. Moreover, excessive staining may not fully penetrate the wood, leading to poor adhesion and premature wear. Additionally, thick layers of stain are prone to peeling, cracking, and blistering as they struggle to bond with the surface. 

Decks require several inspections during and after the building process, but the specifics vary depending on where you live. Most areas mandate that decks comply with local building codes and safety regulations for the foundation, framing, and structure. Some pros recommend a footing inspection, which verifies the depth, width, and location of the various footings to ensure they offer enough foundational support.

Pressure-treated lumber is one of the most affordable types of decking upfront. This material is widely available, so you can usually find pressure-treated lumber at almost any local home improvement store you visit. Keep in mind that wood requires a lot of upkeep with repainting and restaining, so any kind of wood may be more expensive in the long run than something like PVC decking.

It is possible to build your own deck, but it’s typically better to leave the work to a decking professional. Decks can be exceptionally complicated, especially if you want a wrap-around or second-story deck, and you don’t want to risk making an expensive or dangerous mistake. It’s usually better to hire a decking pro who can pull permits and build a structurally sound deck that will last for decades and provide the maximum return on investment.