If you buy something through our posts, we may get a small commission. Read more here.

How To Pour A Concrete Slab For A Hot Tub

by Lianne Jones June 09, 2022

How To Pour A Concrete Slab For A Hot Tub?

Hot tubs are very popular among people who want to relax after a hard day at work.

A concrete pad is one option for a spa base. Concrete is a sturdy material that lasts a long time.

However, it takes skill to install properly, and if you move your hot tub, you may have to redo the installation.

Depending on where you live a  permit may be needed if you want to make any changes to your house or yard including installing a concrete slab.

Before starting to build a hot tub, you should make sure that you have built a strong foundation for it.

You should also take the time to do some research about the type of hot tub that you want to buy.

When considering a hot tub, you may also want to think about getting a portable model if you plan on moving it around often.

A portable hot tub is easier to move than a permanent model because it doesn't require any plumbing. It also means if you ever move home you can take it with you. 

If you decide you want a permanent installation read on to find out how to approach the project. 


Choosing where to place your hot tub is crucial as once it's installed it's very difficult to relocate if you are choosing a concrete base.

Hot tubs should ideally be placed near a drain because they need to be drained regularly.

Placing them too far away from drains can cause overflow problems. You should also make sure the area is level before choosing a spot.

Hot tubs also need electricity to generate heat. Placing them too far from your home may limit your options and increase the cost of powering them.

Make sure you choose a location that provides enough power for you to use your hot tub without having to worry about running out of energy.

If you are uneasy about installing a hot tub yourself you could consider using a professional installer who will always make sure your hot tub is placed safely and correctly.

You should remember that bare ground cannot support the weight of a hot tub so you shouldn't place a hot tub on grass because it could sink into the earth.

You must install the hot tub in a concrete vault if you want to use it safely. For concrete installations, you should use a 4-inch thick reinforced concrete base that supports up to 120 pounds per square foot.

If you’re wondering how you will get your hot tub into your yard do not fear, your hot tub can be delivered by forklift.

We recommend measuring the distance of your hot tub before it arrives. You should also walk the path that your hot tub will travel during transport to make sure there is room to geth through.

Make sure you  measure side yard distances, gates or doors. Obstructions such as trees or shrubbery should be considered to. 


You should place hot tubs in shaded areas away from direct sunlight but in a warm place.

Cold areas tend to freeze water and windy areas blow air over the spa, making it uncomfortable to use.

You could try placing your spa near barriers like solid baffles or fences to create a windbreak.


Before pouring concrete, check the area for potential issues, such as holes or bumps. Fill them in if needed.

Look for tree roots and large rocks and ensure you them before pouring. Make sure the area is flat and smooth before you start. 

The next step is to make sure all of the space is clear for construction purposes (This means removing any trees/shrubs from around).

It‘s important not just because you can get damaged during installation, but also due to roots getting into concrete. You don’t want any kind of tree root coming through our flooring. 


The next step is to start excavating.

Step 1

Dig down to four inches. If you find the ground is extremely hard, dig up to ten feet deep.

A shovel or an excavator should suffice. Don't dig into the soil any deeper than four inches. 

Step 2

Two-by-fours are used to make the frame for the concrete. This makes sure the frame is strong enough to hold up the wet concrete.

Two-by-fours should be cut to make a frame for the wet concrete to go into.

Lumber should be arranged so that the boards overlap. Inside the frame, there should be space for the wet concrete.

Step 3

Measure the frame from each corner and then adjust it until everything is square by measuring from corner to corner.

Ensure the measurement is precise. Make adjustments if their not. 

In this step, the top of the frame should be levelled. It’s important to maintain a slight slope so water is able to flow away.

A concrete slab slope is typically 1/4" per linear foot. The slope should run away from any structures. You can Insert stakes to [revent movement. 

Step 4

Drive wooden stakes every 2 feet apart, and attach them to the frame with 1.5-inch screws. Recheck levels, and square as you insert each stake.

Pouring And Filling

Pouring And Filling

Screed boards are used to smooth out the surface of the concrete before pouring the hot tub form.

A screed board is a long wooden plank that is laid across the top of the concrete slab. The screed board helps create a flat surface for the concrete.

You can use pre-made concrete to save time. However, if you want to buy it separately then remember that concrete sells by the yard.

If you don't know how to figure out how much you need, call your local concrete supplier or you may end up ordering too much concrete, however, it's better to have a little extra than run out halfway through the project. 

Step 1

You need to pour the slab all at once and then tamp it down.   Remove the concrete around the edges. Use the screed board should be used to level a concrete floor.

Step 2

You should place the screed board on the edge at one end. Then two people move the screed board back and forth across the concrete, smoothing out any bumps or unevenness.

After the concrete dries,  remove the screed board and clean up the edges.

Step 3

Use a bull float to smooth the top of the concrete.  Use a 14-inch hand trowel to trowel the surface. Concrete slabs should always be troweled before being edged.

Step 4

Remove the screws and pull the wooden stakes out of the ground. Tap the top of the boards with a hammer to loosen them.

Use a circular saw to cut off the ends of the 2x4s. Use a cordless drill to drive screws into the concrete.

Installing The pavers

You'll want to use at least 2 inch thick pavers. You should dig out an area around the base, level it off, and compact it in the steps above.

Your hot tub will sit on top of this base. Layout yout six inches of gravel, then one inch of sand, then the stones.

Finally, join the pavers together with sand. Pavers are made by mixing sand, gravel, cement, water, and other materials together.

You can expect this process to take a while but the end result will be beautiful foundation for your hot tub!

Less Permanant Options

A less permanent solution is a pre-fabricated spa pad like the Ezy Pad or Handi-pad.

These are pads made out of squares of plastic designed to be strong enough to support the hot tub. They are also modular and come in different sizes. 

It’s worth remembering the smallest available size is 8 by 8 feet, so if you have a smaller hot tub, there will be some exposed plastic around the edges, however, these pads are easy to install and do not require any cutting or shaping of your lawn.

However, you should be aware that they are easily seen when installed, and may not appeal aesthetically to you or your neighbours.

Spa pads are a relatively new invention. They are very easy to install and they are also fairly cheap. They also last for quite some time before needing replacement.

These are great for people who need to travel often, but they do not want to spend much money on a hot tub.

You must use a perfectly flat surface to install a prefabricated spa, otherwise, the plastic might warp and cause problems.


Hot tubs vary in price but on average a  tub should cost around $5,000-$7,000. Inflatable hot tubs cost about $400-$1,500.

Entry-level hot tubs cost around $2,000-$6,000. Value priced hot tubs cost about 3,000-$4,000.

Premium hot tubs cost about 8,000-$11,000 and Luxury hot tubs cost about 11,000-$18,000.

Decking Surround 

Once you’ve installed your hot tub you may want to think about its surround.

A sturdy wooden frame is a simple and effective option and is made of two by fours sandwiched together.

It is an easy-to-make, inexpensive and attractive,  and is a good way of keeping your bathtub off the ground.

Make certain the vertical supports are strong enough to support both the full tub and the people using it. 

This is also a great way because you can raise the tub if one corner starts sinking.

Check the supports first before installing your hot tub and make sure the supports are sturdy enough to hold up the weight of the hot tub.


Installing a hot tub can be an exciting project, with the right tools and knowledge you could be relaxing in your bubbly tub sooner than you think.


Leave a comment

Comments will be approved before showing up.