A cedar deck can increase your home's value if the project is executed well. The value added by a deck is influenced by factors such as location, materials, and craftsmanship. In regions with warmer climates, decks are particularly desirable, enhancing outdoor living spaces.

The key to getting the most value out of your investment, both in terms of home value and personal enjoyment, is to make sure your deck is built to exacting standards. You should consult with a professional deck builder to get the best results and the highest ROI.

For a 12x20-foot (240-square-foot) deck, you can expect to pay between $7,200 and $14,400. This cost is based on a general price of $30 to $60 per square foot. The final price will depend on factors such as the decking material, design complexity, deck type, location, and local labor costs. Keep in mind that add-ons will increase the total; for example, adding an under-deck drainage system to a deck of this size could cost an additional $7,700.

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. 

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.