Can You Fill An Inflatable With Expanding Foam?

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Even though inflatables are meant to be filled with air, it is possible to fill them with expanding foam. The foam will have the same effect on the inflatable as air pressure, albeit with some differences.

For instance, deflating your inflatable product may be difficult because of the rigidity of the foam, so easy storage may be compromised.

Even so, there are several upsides to using expanding foam to fill an inflatable. For one, there is increased buoyancy if the inflatable is a boat or another water vessel. Also, the foam adds protection to your vessel against sharp objects, which translates to fewer punctures.

Even so, experts argue that expanding foam should not always be the first option to repairing an inflatable.

How Do You Use Expanding Foam?

As its name suggests, expanding foam has expanding properties, which is why it is used in the place of air at times.

Basically, it has polyurethane components that react when they come into contact with air, causing the liquid to expand. Some foams can expand up to 150% of their original volume.

Expanding foam is especially good for repairing leaks that a puncture may have caused. To use it, you should make a hole or two at the bottom of the inflatable.

Ensure that the gap is smooth so that the foam does not come out as you try to put it in. Also, the hole should be on the complete opposite side of where the valve(s) of the inflatable is located.

The location of the holes vis-à-vis the valves enables the latter to release extra air and pressure as the vessel expands. The expansion process takes a while, so you should let the inflatable sit a while without interfering with the process.

  • When the valves stop releasing air in the form of foam, you will know that the process is complete.

As for how much foam to use to have the desired effect on the inflatable, it will depend on the size of the inflatable. For this, you ought to do your research so that you don’t put too much foam or too little of it.

The good thing about the packaging is that they come in pressurized cans with straws to make it easy to spray through gaps.

Take a look at this YouTube video that shows how to use expanding foam.

Advantages Of Filling an Inflatable with Expanding Foam

While expanding foam may not be the best alternative to air pressure when it comes to inflatables, it has some advantages. For one, it does a good job when you need to repair a leak fast enough.

As we’ve mentioned above, it has impressive expanding properties that will fill your inflatable in a short time.

Also, it forms a layer on the inflatable that protects the vessel from the effect of sharp objects, especially while in water. Therefore, you will rest assured that your inflatable will make it out of the water unscathed.

Additionally, the foam promotes the insulation properties of an inflatable. This is especially useful on a vessel like an inflatable hot tub because you don’t want to lose the heat of the warm water.

What’s more, it improves the buoyancy of a water vessel for a better fishing or kayaking experience.

What Do You Look Out for In Expanding Foam That Fills An Inflatable?

Type/ brand

Some brands require special training to use with accuracy. Brands that contain rapid-expansion foam are meant for pros who have training on using them safely. As a layman, you ought to go for the consumer-friendly foam that is easy to use to avoid making a bad situation worse.


Choose the size of the can according to the size of the inflatable you intend to fill. If the inflatable is relatively big, getting small cans would mean that you’d need very many of them, which can be cumbersome. Thus, it would be prudent to also go with relatively bigger cans of expanding foam.


There are different brands of expanding foam in the market, each with its own price. The good thing about that is you can always find one whose price range is within your budget. Even so, keep in mind that sometimes, the cheaper a product is, the lower the quality.


As with any other product, it is important to check the quality of the expanding foam before you purchase it and use it. Mostly, it will depend on the inflatable you intend to fill.

Some inflatables will require foam of excellent quality for it to work, and others will be just fine with regular quality foam. It is vital that you do your due diligence.

Ease of use

Remember that a small mistake when filling an inflatable with expanding foam can cause a huge mess. Therefore, it is prudent to go for one that has clear instructions that you can follow easily.

Also, remember to check the expiry date before using the foam.

What Are the Limitations of Using Expanding Foam to Fill Inflatables?

While it has upsides, expanding foam comes with disadvantages too. For one, they can be quite pricey. At times, the total cost of the foam and the delivery cost can be enough to get a new inflatable product.

A solution to this would be taking your vessel to dealers who will do the filling for you at a lower price.

Also, the foam tends to absorb water. Thus, it can get quite heavy, messing with the ease of moving it or even its buoyancy in water. For this reason, it may be better to use it on inflatables that hardly come into contact with water.

The foam can become relatively rigid when it has it has settled in properly. This can make storage difficult, which beats the whole idea of inflatable products.

If you intend to deflate and store your inflatable item often, then you may want to steer clear of expanding foam.

Additionally, the contents of the foam may make it a risk factor, especially where fire is concerned. As the contents make most types of foam inflammable, it is wise to use it away from sparks or any form of fire.

Final Words

Using expanding foam is one of the ways you can fill an inflatable. Expanding foam does impressively well in repairing punctures and preventing air leakages.

Some of the advantages of using expanding foam are that it increases buoyancy, fendering, and insulation of the inflatable.

However, using expanding foam is not always the best option. This is because it absorbs water, makes an inflatable too rigid to deflate and store, and it’s relatively pricier than other options.