Vermiculite For Your Pool Base: Pros, Cons, and Everything Else You Should Know

So, you’re thinking about installing a swimming pool in your backyard. Of the many types of pools you can install, you’ve landed on a vinyl liner pool. Great choice! However, one major decision still remains before you can begin the installation process: What pool base do you want? Vermiculite is one of your options.

But if you’re going to choose vermiculite, you’ll want to first know everything about it, including the pros and cons and how it compares to concrete or grout, amongst other things. So, let’s dive in.

Main Takeaways

• Vermiculite is a pool base that is made up of vermiculite and Portland cement mixed with water.
• Vermiculite is durable, insulating, comfortable, and manages moisture, but it is difficult to install, porous, and slightly more expensive than other pool base options.
• The process for applying vermiculite for your pool base includes mixing the vermiculite with water and applying it with a trowel, starting with the deep end.
• Grout is the most durable pool base option, sand is the most budget-friendly, and vermiculite is the most comfortable.

What Is Vermiculite for Your Pool Floor?

Vermiculite is a natural mineral that expands when heated. However, when it comes to pool construction, we generally use a mixture of vermiculite mineral and Portland cement. When mixed with water, this mixture forms a smooth, durable base. Due to its durable and insulating qualities, it makes an ideal base for a vinyl liner pool. All in all, vermiculite is a long-lasting and stable pool foundation and the main alternative to a grout/concrete pool base.

Pros and Cons of Vermiculite as Pool Base

So, why should you pick vermiculite? To make a well-rounded decision on what to use as your pool base, you should weigh both the pros and cons.

Pros of Vermiculite as Pool Base

Here are the main advantages of using vermiculite as a pool base for your vinyl liner pool.

Durability

Vermiculite is mixed with cement, creating a very durable and long-lasting base that can withstand general wear and tear, including some ground movement and any temperature fluctuations. If you apply and mix it properly, you are not very likely to come across any structural issues.

Insulating

Vermiculite is naturally insulating, meaning it can help maintain a consistent water temperature for your pool. The naturally insulating properties reduce heat loss, which can help save money in the long run.

Comfortable

One of the main reasons pool owners and professionals opt for vermiculite over grout or concrete is that this material is smooth and non-abrasive. Vermiculite is much softer and more comfortable for swimmers, making it an excellent choice for swimmers with sensitive feet.

Cons of Vermiculite as Pool Base

Here are the drawbacks to using vermiculite as your pool base.

Installation

Unfortunately, vermiculite can be difficult to apply. To mix and apply it properly, you’ll likely need to hire a professional who knows what they’re doing. There are a couple of different issues that make vermiculite relatively difficult to work with. First, once applied, removing or reshaping it is difficult if you make a mistake. But this shouldn’t be an issue if you apply it correctly in the first place. Second, vermiculite is a rather lumpy material, so it’s difficult to smooth and level it properly in the first place.

Porous

Another disadvantage of vermiculite is its porosity. Due to its porous nature, vermiculite absorbs water, which may ultimately lead to the liner floating if not properly managed.

Cost

Vermiculite offers many benefits as a pool base, but it is certainly NOT the most cost-effective option. It is a bit more expensive than other pool base choices, such as sand or grout.

The Process for Applying a Vermiculite Base

Unless you have experience with vermiculite already, I wouldn’t recommend applying the vermiculite as the pool base yourself. More likely than not, you’ll need to hire a professional to take care of the entire pool building process for you. But just because you won’t be doing it with your own hands doesn’t mean you shouldn’t be ignorant of the process. Understanding the process for applying a vermiculite base allows you to better understand how construction is going and keep an eye on everything. Here are the key steps involved in applying a vermiculite pool base.

Step One: Site Prep

Of course, first things first, before you can apply the base, you’ll need to prepare the pool site by excavating the area to the depth and shape needed to create the pool. Make sure the base is clean and solid.

Step Two: Mix the Vermiculite

It is important to get the right mixture of vermiculite and water to get a thick, mud-like consistency. If you add too little water, the mixture will be too dry and difficult to smooth out. If you add too much water, the base will be too soft. Mix the vermiculite and water thoroughly to ensure everything is properly distributed.

Step Three: Apply the Vermiculite

And now for the hard part! Start with the deepest part of the pool, working your way up to the shallow end so that you can back yourself out without stepping on the still-drying vermiculite mixture. Use a trowel to spread and smooth the mixture, working your way up. Make sure to apply the vermiculite in even layers, around 1 to 2 inches thick.

However, as you trowel and apply the vermiculite, the important step is to smooth and shape it as you go. Pay attention to creating a consistent slope and ensuring the surface is even. Remember: vermiculite is pretty difficult to reshape, so work quickly and evenly.

Step Five: Allow to Dry

Once applied, you should allow the vermiculite to dry overnight before continuing with the pool building process.

Step Six: Perfect the Base

The next day, before you continue with installing the vinyl liner, sweep up the pool base to get rid of any loose vermiculite and other debris that might show underneath or (god forbid) tear the liner. Fill any holes and smooth any bumps. Ensure the vermiculite base is as smooth as possible!

Grout vs. Sand vs. Vermiculite for Vinyl Pools

Vermiculite is a popular choice as a base material for a vinyl pool, but it’s not your only option. You can also opt for grout or sand. Let’s compare these three options so that you can make an informed opinion on which pool base material is best for you.

Grout

Grout is the most durable and solid surface you can choose for your pool base. It is resistant to damage from pool equipment and heavy use. It is also better at keeping any groundwater away and does not need any floor repairs whenever you replace the liner (which is sometimes the case for vermiculite) due to the sheer durability of the material. However, it’s worth noting that grout may need maintenance to repair cracks.

Sand

Sand is the most affordable option for a pool base, making it a great alternative to grout or vermiculite for pool owners on a budget. It is the easiest material to work with, reducing installation time and labor costs. However, on the flip side, sand is a soft material that may shift and settle over time, potentially leading to an uneven pool floor, which may require more maintenance than grout or vermiculite.

Vermiculite

Vermiculite is a great option for pool owners looking for a soft, cushiony surface for swimmers. It is insulating, helping to maintain a more consistent water temperature. While it may be more challenging to apply than grout due to the consistency, as long as you hire a pool professional familiar with the material, you shouldn’t run into issues during installation. Compared to grout, one disadvantage of this material is that vermiculite is porous, which means groundwater may come in, causing the liner to float.

Frequently Asked Questions

How long does it take for a vermiculite pool base to dry?

Vermiculite takes around 8 or more hours to dry. Typically, you will allow the material to dry overnight before continuing with the pool installation process.

What is the best material for the bottom of a vinyl pool?

The best material for a pool base is grout/concrete or vermiculite. Both are durable and much more suitable for creating the base for your pool than the third option, sand.

Choosing Vermiculite as Your Pool Base

As you can see, vermiculite is a great option as a pool base for your vinyl pool. Whether you go for vermiculite, grout, or even sand is ultimately up to you, your budget, and your priorities. If you pick vermiculite, hire a professional who’s worked with the material before for the best results!

Do you have any more questions regarding the installation process for a vinyl swimming pool? Let me know.