Do I Need A Mat Under A Hot Tub?(Guide)

Do I Need A Mat Under A Hot Tub?

Do I Need A Mat Under A Hot Tub?

A Hot tub mat is one of the essential accessories to have in your hot tub. Hot tub mats are a type of cushion that is made out of polyester fabric.

They may also be called hot tub pads, often used to prevent slipping and the risk of injury when getting out of or going into a hot tub.

Yes! You can use a Mat or a ground cloth to create a level surface for it to sit on. You can also use a Mat to protect the bottom of the hot tub from getting scratched or scraped by your patio, deck, or ground surface. Your hot tub may come with a Mat as standard equipment, but purchasing one is a good idea if it doesn’t.

The mat size you need depends on the size and shape of your hot tub.

You can buy custom fit mats in some retail stores that sell hot tubs, or you can buy universal fit Mats that may or may not work for your hot tub, particularly if you have a unique or odd-shaped unit.

There are only two rules when it comes to using a Mat.

First, always make sure that the Mat is always flat and level. The floor of the tub should be perfectly flat. Second, place the Mat on the ground.

Never place your hot tub on a Mat directly on the floor of your patio, deck, or ground surface.

This could damage your hot tub and may also cause uneven heating and temperature distribution inside your hot tub. Make sure you have enough room for the Mat to sit flat and level on the ground.

What Kind of Base Do You Need Under a Hot Tub?

Base AlternativesFeatures
Existing Patio-Concrete, Masonry, stone or brick and wood
An Existing Deck-A wooden deck, cedar, vinyl and masonry deck.
Concrete Base-6″ ,8″
 A Dimensional Concrete Pad-5’x5′,  6’x6′,8’x8′
 Paver Stones-6″x6 ,  8″x8″12″x12″
A Dimensional Concrete Pad With Pavers-5’x5′ ,  6’x6′

Do I Need a Mat Under My Lazy Spa?

Yes! If you have a vinyl liner or gunite pool (concrete), you need a Mat because there is less friction between the pool floor and the Mat.

The Mat will keep you from damaging your liner or concrete by slippage as you move in and out of the pool.

If you have a tile or pebble-tec pool or concrete deck attached to the inside of your pool, you should be fine without a Mat.

Here are three alternatives to a mat

Pool Liner Or Gunite

You can use a pool liner with the cross pattern, but on purpose or by mistake, you will only scratch your liner if careful.

This is also one of the reasons a pool Mat is recommended – To protect your concrete, and it’s easier to mop the floor than to clean the scratches from an already damaged cement pad.

Tightly woven rug-like material -Tightly stretched and nailed down at all four corners of your Spa area (on the ground).

This will work better than a tarp, but it will only last for a while. The Mat will last longer if it is tightly stretched and nailed down at all four corners of your Spa area (on the ground).

Do I Need A Mat Under A Hot Tub?

Sit On The Sides Of Your Spa And Do Not Walk Around Your Spa Or Use The Steps.

This works well if you don’t get in the pool often and don’t want to spend much money.

What Do You Put Under a Spa?

Putting a Concrete Pad/Slab under a Spa would be best. Concrete is porous, which means it can soak up the excess water from a pool or Spa so that your flooring and the surrounding area stay dry.

A concrete pad can also provide a lot of warmth to a Spa or pool water for an added thermal effect.

The concrete pad is frost-resistant, so you won’t need to worry about melting it with the sun in your backyard.

Finally, a concrete pad will last for years of heavy usage and abuse, making it worth the expense over other materials like sand or gravel.

You can build a concrete pad or order a pre-built one from your local home improvement store. The concrete pad should be 4 inches thick and large enough to accommodate the entire Spa or pool.

The best way to ascertain if you need a concrete pad is to measure the space inside your pool.

Consider the overall shape of the Spa before you decide on the final size of your pad.

A rectangular shape will work well with a concrete pad, while a circular shape may require that you build two larger pads with the same diameter.

What Level Does a Hot Tub Need to Be?

Multiply the result by 2.4 if the hot tub has seats or 4.8 if the hot tub doesn’t have seats. The result is the estimated number of gallons the round hot tub will hold.

Example: If the square hot tub has seats, the result is 31 gallons. If it doesn’t have seats, the result is 62 gallons. The approximate hot tub capacity is 62 gallons x 2.4 gallons per gallon = 143 gallons.

The user can calculate the amount of hot water needed for each guest by dividing the total amount of hot water needed by the capacity. The result is the approximate number of gallons needed for each guest.

Example: If a guests bathe in a 20-gallon hot tub and fill it to 80% capacity, the result is 20 gallons x .82 gallons/gallon = 17.8 gals/guest (17.8 gallons per guest).

Hot tub manufacturers use an industry standard to determine how much water each guest needs.

Manufacturers determine the gals/guest or the number of adults needed by multiplying the average size (adult) in inches by 100. The result is their weight in pounds.

This result should be divided by two because each adult will need a temperature setting of 103° to 104°F and a water volume of 52 gals per hour.

Example: If a guest is 6 ft. tall, multiply 6 ft. (adult average) by 100 = 600 lbs. divided by 2 = 300 lbs./hr.

Now that you have calculated a guest’s temperature load and energy-heating volume and capacity, you can determine how many adults the hot tub needs to accommodate.

The number you get is the approximate number of adults that will be in the hot tub at a time.

Example: If the guest was 6 ft. tall, multiply 6 ft. x 300 lbs/hr = 1800 lbs. divided by 2 = 900 lbs./hr.

Using these formulas, users can determine how many adults they will accommodate in their whirlpool spa.

How Much Slope Is OK For the Hot Tub?

The slope of your hot tub is essential for maintaining a healthy and relaxing Spa experience, but too much slope can wreak havoc on your body.

According to Tifosi’s Creative Hot Tub Solutions, a ½” (1.27cm) slope in an 8′ (2.44m) run is ideal.

If your hot tub has a slope that’s higher or lower than ½” (1.27cm), you must adjust the jets so that they consistently pressure the water.

Otherwise, high-pressure jets (made for cold water) will push against hot water and create an uncomfortable pool effect.

In contrast, low-pressure jets will cause water to dissipate more quickly than desired and create a soft, inconsistent feel throughout the Spa.

Water temperatures vary from person to person, so what’s optimal for one person may not serve your needs. So, measuring your water temperature and adjusting it accordingly is essential.

Using Tifosi’s Jet Controller, you can easily adjust the water temperature of your hot tub so that it matches your heat preference.

You can perfectly match the water temperature in your Spa with Tifosi’s Jet Controller, which allows you to control the jets on a per-jet basis.

For example, suppose you have some jets in the middle of the tub that deliver hot water to your skin but others on either side that produce freezing water.

In that case, you can set these two jets to operate at different temperatures to deliver consistent and pleasurable water flows.

How Do You Pour a Pad for A Hot Tub?

Spread and level an inch of fill sand in the bottom of the pad forms– Fill sand is made of tiny granules, which will help the pad to drain and stay firm.  

– Fill sand should cover all the edges of the forms.

Pour a depth of 2 inches of water into each form and move back about 4 feet away– You need to keep plenty of space around your tub for easy access later on if needed.  

– Once the water level reaches about an inch from the top, stop pouring and add concentrate by hand.

– Add enough water to dampen the sand so you can easily form the pool into perfect spheres.

– When you finish pouring, move back a few feet away and blot up any excess water.

Connect your hose to a pump and one end to the form with the hole.– Carefully fill the hole in this balloon-shaped form with the concentrate by hand,  

– Slowly fill the rest of the forms using pumps attached to hoses connected to your fixture (s).

– You may have to refill some of the forms twice.

Set up your Pool– Fill the holes with concrete as you fill them with water, and pour it over smooth siding or even on top of the decking, whatever is easiest for your setup.  

– Once you finish lining the bottom, cover your work with a tarp to protect it from heavy rains or snow melts coming off roofs.

– Once all the holes are filled with your concrete, pack the sand back into the forms and let it dry for a few days.

How Much Does Pouring a Concrete Slab for A Hot Tub Cost?

When you pour a concrete slab for a hot tub, you’ll need a sub-base (this is just dirt), tampers, and steel forms.

The total cost would be between $500 and $2,500, depending on the size of the hot tub, how much it weighs, and the level of finish you want.

Here’s the breakdown:

Sub-Base: $500 – $1,500. The sub-base is just dirt, so it’s inexpensive. You can buy a small lot of topsoil at a nursery and spread it out over your sub-base.

Topsoil has intact clay, forming an almost impervious surface that you can mold into a shape to support the tub.

Form: $250 to $1,000. These steel forms go for about $600. They cost so much because the forms are reusable.

You would need a dozen to make a hot tub big enough for six adults. If you don’t want to reuse the forms, you can buy just enough to complete your project.

These are heavy and awkward things to work with and would cost around $250 per form.

Concrete: $250 to $1,500. The total cost of the concrete will vary depending on the quality and amount you mix.

For a high-quality concrete with a low water-cement ratio, you’ll need about 3 cubic yards for a 10′ x 10′ slab.

The cost per cubic yard would be about $120. This will give you a rough surface that is easy to finish with sand and sponge, but it won’t be smooth or glossy like professional concrete slabs.

Tampers: $100 to $300. You’ll also need a minimum of two tampers for a 10′ x 10′ slab. They are long metal rods that you use to press down on the forms, so the concrete has something to rest on so it hardens.

You’ll need at least two because you may mix up too much or mix the concrete in a way that doesn’t work well with one tamer.

If you have a former hot tub still in good shape, you can use its form to weigh it down.

Spackle: $10 to $10 for a gallon. You’ll need one gallon for every four cubic yards of concrete you mix.

This is called the makeup water, and it helps the concrete slump into a smooth shape and prevents air pockets from forming.

Sand: $3 per bag. You’ll need a few bags of sand to finish the surface so it is smooth.

Sponges: $3 per sponge. You’ll need a few buckets of sponges to finish the surface with. This will give you a reasonable, not glossy, finish.

Miscellaneous: $50 to $200. You may need other materials such as powdered limestone for water-cement ratio, gloves, aprons, shovels, wheelbarrows, cement mixers, or other forms.

Will My Concrete Patio Hold a Hot Tub?

Yes! Cement is porous, so it can absorb water over time. But the hot tub will not negatively affect your patio’s structural integrity.

It is possible to have a hot tub on a concrete patio, provided the cement has been properly mixed and cured.

Since no cement materials are present that would hinder its ability to hold water, you can expect your patio to be an ideal location for a hot tub.

On the other hand, wood decks are not compatible with hot tubs.

The wood in a typical deck will eventually expand and warp as it absorbs water, while any moisture absorbed by your patio will remain.

As a result, the wood will become susceptible to cracks, gaps, and other defects that could be dangerous for you or your guests.

It would be best if you also kept in mind that the hot tub will add additional weight to your patio.

If you have a smaller hot tub, this may not be an issue, but if the hot tub is large and heavy, consider reinforcing your patio’s foundation before setting up the Spa.

This is particularly important if your patio is on a hill or softer ground since the extra weight could cause your patio to sink or shift over time.

If your patio is made of concrete, the hot tub can’t roll or shift during its operation. But if you have a wood deck, you should use caution when using the hot tub for a family gathering.

If your guests find even the slightest crack on the wood deck, they may slip and fall, resulting in serious injuries.

How Do You Prepare the Ground for A Hot Tub?

  1. Remove all plants and shrubs.
  2. Apply a layer of mulch on the ground, approximately 10cm deep. This will keep weeds at bay and retain moisture in the ground.
  3. Pour water over the hot tub site to flatten out any bumps in the ground. This also helps remove any debris or grass clippings that may be present on top of the surface.
  4. Lay the hot tub on its side in its intended location. The ground surface needs to be below the level of the tub when it is filled with water. The tub can sit directly on the ground, or you can use a gravel bed or another suitable area for sitting on.
  5. Excavate an area around the tub to create a solid 3-4″ foundation of compacted soil around the hot tub. This will help ensure that your hot tub is stable and doesn’t sink over time.
  6. Lay the hot tub onto the foundation of compacted soil and level it.
  7. It’s a good idea to drive a few metal stakes around the edge of the hot tub to help keep it secure in its position while you fill it with water and cover it with dirt.
  8. Fill your hot tub 2/3 full with water, let any air bubbles escape and then pour out your water.
  9. Cover the hot tub with soil and level it. Water will still be in the tub, and the dirt keeps that water in place.
  10. Add more soil to cover the tub until you have a mound of dirt around your tub about 2 feet high. You may need to remove some of this dirt once you are finished building your deck and leveling it out on top of the ground.
  11. Finally, you may wish to install some landscape fabric or weed block under the tub to prevent weeds from growing under the tub.

You can leave this in place once your hot tub is installed or remove it and add mulch after the ground settles and you are sure everything is coming up well.

  1. Now, you can move on to building your deck.


Hot tub matting is a quick and easy way to cover your hot tub while maintaining its appearance. It’s also relatively inexpensive, so it’s worth considering if you have the time and space.


Hi! I' am Tom. I was a manager in one of the biggest stores for over 10 Years, am also an SEO by night. I don't like to call myself a blogger; they are very analytical, do email marketing, and know all SEO stuff. I faced many questions from customers about different products, and there was hardly any help on the internet. After learning all the things about these products as a manager the hard way, I decided to start a blog and help other people.

Recent Posts