We have an 8' x 10' deck off our second-story master bedroom in Greenville, South Carolina. It is braced with 2" x 8" supports. What's a rough cost, if it's even feasible, to strengthen the deck and add plumbing to accommodate a 2-person hot tub? Plumbing access (sink, toilet) from the bathroom is close by on the same exterior wall.
Thomas O. ~ Greenville, South Carolina
Thomas, if you want to install a hot tub on your home's deck, then it is imperative that you add extra supports to the existing 2x8's that hold up the second story deck. A 2-person hot tub can hold between 200 and 300 gallons of water, which means that a full tub can weigh between 1,600 and 2,400 pounds! With all of that weight, some 8x8 posts might offer you more peace of mind while soaking in your new tub. You may also have to pour some new cement footings to support the additional weight of the tub and the new wood posts, because the existing footings were probably not designed to support a hot tub. I would consult a contractor in the Greenville area who can inspect the existing deck support and footings and then offer a plan for dealing with the added weight of a full hot tub.
When considering how best to deal with the tub's plumbing, I would avoid extending water lines to the outside of your house altogether. Even in South Carolina, outside water lines can freeze and burst during cold winter weather. It would be better if you use a hose, which is connected to a frost-free hose bib, to fill the tub. Most hot tubs are self contained units anyway, meaning that they are not permanently connected to water and waste lines like an indoor tub or jacuzzi. You simply fill the tub from a garden hose, and then use a hose to drain the water out when the tub needs to be cleaned or emptied.
I estimate that it should only cost about $500-$1000 to beef up the supporting deck structure, depending on whether or not new cement footings are necessary. I hope that you enjoy your new hot tub and best of luck with your project!