The closer your hot tub is to your house the more likely you are to use it, but can you install one on a deck? What about an elevated deck? As a general rule of thumb if your deck is raised a couple feet or less off of the ground it should support about 100 pounds per square foot. If it can’t there are options like adding additional support beams underneath it. Let’s learn more about how to install a tub on your deck. 

How to Determine if Your Deck Can Support a Hot Tub

First you’ll need to know how much your hot tub weighs. Here are some rough estimates: 

• A small 2-3 person tub weighs about 600 lbs empty, 2,575 lbs with water and 3,000 lbs occupied.
• A medium hot tub weighs in around 750 lbs, 3,700 lbs filled and 4,420 with people.
• A large 6-8 person tub weighs 800 lbs empty, 4,300 lbs with water and 5,500 lbs with people. 

Next you’ll need to calculate your deck load capacity. Your values are: 

1. The weight of your empty tub: 1 gallon of water = 8.34 lbs
2. The average weight of a person: 185 lbs and the square footage of your tub. 

With these values you’ll then use the following formula: 

[Weight of Hot Tub + (Number of Gallons of Water x 8.34 lbs) + (Number of People Spa Can Seat x 185 lbs)] / # of Square Feet = Pounds Per Square Foot.

If you’re building a new deck, then you’ll want to ensure it can support the weight; if you’re working with an existing deck, you may need to build an additional support system. We recommend having a professional contractor inspect your deck to determine if it can handle the tub. The contractor will look at the structural integrity and make sure that the structure can support it.

Considerations for Installing a Hot Tub

A flat, level surface such as a concrete slab is the ideal location for a hot tub. If you’re building a new deck, the slab should be formed and poured at the same time as your concrete footings. A 3-1/2 to 4 inch slab is usually sufficient, however larger tubs may require something more substantial. If your tub will be on a concrete slab, the electrical wiring must be run in conduit and placed before the concrete is poured.

You’ll also need a nearby electrical source to power your tub and a licensed electrical contractor to do the work. Since water and electricity never mix, a ground-fault circuit interrupter (GCFI) is also a must-have. Some smaller spas can be plugged into a GFCI-protected 110v/20-amp outlet but larger units usually require a 220v/50-amp connection to work properly. A nearby emergency shut-off is also usually required.

Don’t forget about the water! Especially if you’re planning to put your tub on a second-floor deck, consider how you will fill and drain it. Do you have a spigot nearby or will a garden hose be able to reach it? And where will that water go when you drain it (considering that most tubs need to be drained approx. every 6 months). 

Owning and maintaining a hot tub can seem overwhelming, but we’re here to help so you can enjoy all of the relaxing benefits of having one. Give us a call with questions at 970-879-4390 or contact us here.