Hot Tubs & Decks 2022 – The Complete Guide

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hot tubs and decks

Decks have a lot of uses for their space, including gatherings, grills and the ever popular hot tub. Not every deck is capable of having a hot tub installed or mounted, though, and a lot of considerations need to go into the planning.

If you plan to put a hot tub on your deck, though, you are in the right place. In this article we will cover deck construction and hot tub installation, weight limits, plumbing and answering your questions along the way.

Why Hot Tubs and Decks Go Hand in Hand

One of the great things about decks is that they are so versatile. But what makes hot tubs such a popular option? Let’s take a look at the top reasons.

  • Easy access. Having a deck leading to your hot tub allows you to walk out of your door and directly to your hot tub without having to cross your lawn.
  • Keeps things clean. Decking provides a barrier from ground-level contaminants getting into the hot tub offering less cleaning and maintenance in the long run.
  • Install on any level. Ground level decks, raised decks and even second story decks can all support hot tub installation.
  • Year round use. With a hot tub installed on your deck, your backyard space becomes usable at any time of the year.
  • Great for gatherings. While a new deck is cause for celebration and entertaining, nothing completes a great summer evening gathering like finishing the long day in a hot tub.

Buyer’s Guide: Choosing the Right Hot Tub for Your Deck

buyers guide hot tubs and deck

Before you start building your deck you need to plan for your hot tub installation. Assuming you don’t already have a hot tub/spa or are looking for an upgrade, here are some consideration factors to think about before you buy.

Hot Tub or Spa?

Most people use the terms hot tubs and spas as the same thing. In effect they are, but when shopping through a dealership you want to use the right terminology so you end up with the right product. Both options heat water but only a spa has water-circulating jets.

Insulation Factor

Because your spa will be on a concrete slab or elevated off the ground, insulation becomes a much larger factor. You want closed-cell “full” foam insulation to help prevent heat transfer loss and sound dampening.

Size Considerations

Hot tubs and spas come in many sizes, shapes and depths. You want one that your family can fit into comfortably, but also one that fits your budget. The best option is to test them in person. Get in one and see how much room you have to stretch out and relax. 

Install Method and Location

Installation is also critical. Hot tubs are large, bulky items and will need to be delivered to you. Set up and install can be a DIY project, but it is worth the extra fee to have the delivery drivers bring the spa close to its final installation area so you have less work to do when the time comes.

Warranty

Warranty coverage is also important, but you need to be cautious. Some brands and manufacturers will require professional installation for the warranty to be valid. Others may require shipping and return of the spa for a warranty claim. Make sure you understand the warranty details before you buy so you don’t get stuck.

How Much Weight Can a Deck Hold?

Full of water, a hot tub or spa can end up weighing as much as a small car. You need to ensure that your deck build can handle the weight. You will see a lot of builds with the hot tub off the deck and on a concrete slab for this very reason.

For example, a spa 8 foot wide with full water and 4 or 5 people inside can weigh over 7500 pounds. You will need to consider joist and beam strength, post and footing size and other deck-weight distribution factors. A standard deck cannot support the weight of a spa without reinforcement.

However, if you are building your deck with the spa in mind, things are a bit easier. Professionals will use calculators designed for these specifications. You will almost certainly also need a permit for the install.

On average a standard deck is designed to hold 40 to 50 pounds of dead-load weight per square foot. Dead load weight is the weight of objects that are stationary. Live-load is the additional weight of moving things, like people.

How to Reinforce a Deck for a Hot Tub

how to reinforce a deck for a hot tub

If your deck is off ground level and you want to install your hot tub on the deck, you need to add structural support beams. You also need to get the spa on the deck, which may require removing railing, using a lift or hiring a professional to perform the installation.

Assuming your deck is already built, you will need to plan for the weight, size and installation location of the hot tub. In most cases, decks are built around a hot tub that is installed on a level concrete slab. This minimizes the actual weight on the deck and gives you more freedom for installation styles.

The reinforcement of the decking goes far beyond just adding a few pieces of lumber. You need to consult your permits, use weight distribution calculators and find out how large your beams need to be, the new joist spacing requirements and other factors, such as the type of hot tub you are installing.

Once you have the dimensions and weight analysis results, you need to add structural supports, footings, beams and joists to accommodate the weight you will be adding. Most raised decks will have a more normal installation of joist and beam spacing everywhere else and only be reinforced where the hot tub is located.

Can you Put a Hot Tub on a Deck?

Setting the hot tub or spa on the deck is also a viable option. Again, the deck structure and support needs to be in compliance with all codes and capable of holding the extra weight.

If you decide to place the hot tub on the deck instead of building the deck around the hot tub, you need to ensure the deck is level, sturdy and within specifications. You also need to account for water damage, connection locations and power supplies. We will cover these in more detail further below.

Spa positioning on the deck needs to follow the “measure twice and cut once” rule. Once installed and connected, it is difficult to move the spa to a new location. Think about viewpoints, from inside the spa, and also from inside the house looking out into the yard. Clearance and view are just as viable as support and weight limits.

Installing a Hot Tub on a Raised Deck

installing a hot tub on a raised deck

Raised decks are among the most common found in the country and account for most hot tub installations as well. A raised deck is any deck 30 or more inches off the ground. It is still advised to use a concrete slab to place the hot tub on, but this isn’t always viable.

Just keep in mind the additional live and dead weights and your deck construction needs and you will be fine. The biggest concern will be the location of the spa and access to the connections and power supplies. 

Framing and Spans

The first step is to determine where your spa is going to be placed. This will tell you where the most support needs to be when you frame your deck. Footing and framing will be critical around this area and you need the proper spacing for the posts to support the beams and joists.

Once your frame is set you need to add the proper beams, which should be double layered instead of single to help prevent sag and cracking over time. Using two 2×6 or 2×8 boards is better than using a single 4×6 or 4×8, for example.

The width of the board will tell you the strength (in feet) for the spacing. On a standard deck with 50 pounds per square foot, you want to space your beams the number of feet equal to the number of inches of width. For example, a 2×8 beam can span 8 feet.

For the spa or hot tub installation location, though, this span will be smaller. Depending on the calculation you made based on weight and size measurements, this can be anywhere from 2 foot to 8 foot spans.

You will also need to properly span your joists around where the spa will set. Additional weight means a smaller span distance (on center) for each joist.

If you are setting the hot tub on the deck, you can now place your decking boards. If the spa is going to be built into the deck, it is time to place it now, then add the deck boards.

Footing and Posts

The footing and post placement is the most crucial of the entire build. It is recommended to use 6×6 posts for all raised decks up to 6-foot off the ground and 8×8 posts for heights greater than 6 feet.

The footing should be reinforced concrete that extends to at least 1 foot below the frost line or into the bedrock (whichever comes first). The hot tub location area needs additional footings and posts to support the weight. It is recommended to place supports at the four corners, middle of the four edges and in the center of the hot tub location.

Lift Out Hatches and Access

The hot tub will have water connections, power supply connections and a service panel. It is important that you accommodate these areas when laying your deck. The most common option is to install a lift out hatch where these panels are located.

With a lift out hatch you can remove a section of the decking to gain access to the panels or connections without having to crawl underneath or remove a permanent section of the deck. Hot tubs installed on top of the deck don’t normally have this problem, but placement and positioning of the tub are more critical.

Frequently Asked Questions

faq hot tubs and decks

In this section we will answer some of the more common questions about hot tub and deck installation. If you have further questions or concerns, please use the comment section found below the article.

Q. How thick should my concrete slab be for hot tub installation?

  1. It is recommended that you pour the slab at the same time you pour the concrete for the footing and posts. The slab should be a minimum of 3.5 to 4 inches thick to accommodate the weight of a standard 4-person hot tub. Larger tubs or bigger capacity tubs may require thicker slabs.

Q. How can I measure everything before I buy?

  1. The best method to ensure a seamless and easy install is to buy the hot tub first. Once the tub is delivered you can take exact measurements that aren’t available online or seen in the showroom. If this is not possible, the best option is to contact the customer service or technical support for the company selling your chosen hot tub. Get exact dimensions from the manufacturer, just double check before you put the hot tub in place.

Q. Do I need a permit to install a hot tub?

  1. In most cases because of the load and weight limits of a standard deck, you will need to get a permit to add a hot tub. If you are building the deck alongside the spa install, you will need a permit for that, as well and can get one permit to cover both applications.

Q. How do I know how much water weight my hot tub can hold?

  1. If you already own the hot tub look inside the water pump panel. The specifications label is generally located there. It will tell you all of the weights and measures you need. If the label is missing or cannot be read, you can get an estimate with simple math.

Measure the length, width and depth of the tub and multiple these three numbers together (in feet). This will give you the volume of the tub in cubic feet. Multiple this number by 62 (pounds per cubic feet of water) to get the weight of the water that your tub can hold.

Conclusion

Hot tubs and decks are a partnership as old as time. Installing a hot tub on your existing deck will require new beams, joists, posts and footings. However it can be done. Building a deck around a hot tub is a more DIY friendly method as long as you also build the concrete slab for the hot tub to rest on.

There are many factors and considerations that go into adding a hot tub or spa to a deck and hopefully this article has answered your main questions. If you need assistance in installation or getting quotes, check out our free app to get in touch with licensed professionals in your area.

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AUTHOR

Nora has more than 5 years experience in the floor covering industry, acquiring vast knowledge about installation and material selection. She now enjoys working as a writer and an interior decorator. Her work has been featured in The Spruce, Homes & Gardens, Southern Living and Real Homes. See full biography here.

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