Can You Use Expanding Foam Around a Gas Pipe? (Explained)

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You can use expanding foam around a gas pipe as it is easy to apply. It expands to fill the gap, unlike the other sealants and caulk, for this reason, most of the homeowners prefer it more. Moreover, the foam always takes the shape of the gap after it cures and thus, creates an airtight seal.

Construction foam in the cracks of the wall at the construction site

How Do I Fill the Gap Around My Gas Pipe?

There are a variety of ways you can fill the gap around your gas pipe. Here are the most popular techniques;

Opt for a Spray Foam

Even though many people prefer using Great Stuff, this is not the only brand you can use as there are also others like Loctite Tite. Most of the spray foams are practically liquefied polyurethane. This, therefore, expands to a hardening foam that fills the holes up to at least two inches.

Polyurethane is inert and also has limited to no environmental influence. It also attaches permanently. The hardened foam does give thermal insulation and is impenetrable to pests.

The rodents can not bite on through it and when you apply it well, it will leave no spaces for the insects. Great Stuff can help you keep away the pests and you may consider using it, however, it doesn’t have any pesticides.

Use a Patching Compound

This is also an amazing way to fill the gaps around the pipes. The compound you will use is a powder and it makes the rock harder when mixed with water. Trowel it in and give it one hour to set and then apply it.

Besides, it is easy to sand. You can finalize it with paint to prevent the mark created from being visible.

Use a Caulk

Consider a caulk as it can help fill a gap that is less than half an inch wide. Further, you can fill the wider openings by packing them with steel wool and adding caulking on top of it. Acrylic caulk is easy to apply and can fill small gaps which are not more than one-quarter inches.

It is also lasting, though it can shrink as time goes by. And so, this makes it ineffective for larger holes. You can wipe the area around the gas pipe using an old handheld duster or paintbrush to clear the dirt and other debris.

You can use exterior grade caulking to load up a caulk gun and apply an even cord or bead of the caulking around the pipe’s perimeter. And then clean it smoothly with your fingers.

How Do You Apply Spray Foam?

You can easily apply spray foam, though you need to be careful since it sticks on everything. Besides, it can be very hard to wipe out. Solvents also cannot dissolve the foam and in case it gets in contact with your hand, it will need mechanical removal.

Additionally, since you cannot remove it from the fabric, you can wear disposable clothing anytime you use it. You’ll get the foam in a sixteen-ounce can alongside a removable application pipe. You can fit the pipe on the nozzle, and then place its end in the gap.

Go ahead and press the trigger and fill the gap close to halfway. It will expand to finalize the task. Once you are done spraying, you can cover the pipe’s end instantly.

This will help you avoid dripping any traces of the liquid in places where you wouldn’t want to do that.

Can I Use Expanding Foam Around a Gas Pipe?

You can certainly use expanding foam around a gas pipe as it is conveniently packaged and thus also simple to use.

The foam is well formulated to be able to cure even after being exposed to the moisture which is present in the air. And unlike other sealants and caulks, this foam does expand to fill a hole or gap.

After curing, it takes the shape of the hole and then creates an airtight seal. Moreover, the best thing about it is, it does not shrink and always maintains its sealing properties forever.

Expanding foam usually performs two vital roles which include sealing and insulation to prevent extreme temperatures and moisture.

Still, it sticks to a majority of surfaces like plastics, glass, masonry, metal, and wood. It also doesn’t contain any solvents and can never crack or even dry out. It also withstands contraction and expansion without having to pull away as the common sealants do.

Can Expanding Foam Catch Fire?

Expanding foam can catch fire especially if you handle it carelessly. It is always used in do-it-yourself projects to fill and fix gaps. Furthermore, methylene-diphenyl-diisocyanate which is a propellant gas that is used to administer the foam is highly ignitable.

The gas is usually emitted from the expanding foam since it expands and then dries up. It is also heavier than air, thus, can sink and generate an invisible cloud. And in case a source of ignition is available, this gas may catch fire.

This can be with an explosive force. And because of that, your room needs to be well ventilated anytime you apply the foam. This is mostly if it is a confined area. As curing plus hardening takes place, you can still maintain the ventilation.

Make sure there aren’t naked flames like gas cookers and candles as the form is applied and also when curing.

Can I Seal Around the Gas Pipe?

You can seal around the gas pipe and different ways can help you to do so. Though some homeowners always realize whenever they try to seal their gas lines, pests often return after a while. And the sad truth is, caulk or other types of sealants from home improvement shops cannot fill the gap.

Hence leaving behind tiny cracks that can allow bugs or cold air to enter your house. Moreover, when you apply a stiffer sealant like cement, it can destroy the gas line, thus resulting in issues regarding fireplace performance and also safety concerns.

It is also advised that homeowners have an expert fireplace or chimney firm seal the gas lines.

This is because of the risky nature of the lines coupled with the very small area that should be filled. Reaching out to a professional to do the work will ensure the gap is well sealed without interfering with the gas line.

Construction foam in the cracks of the wall at the construction site

Is Expanding Foam Removable?

Expanding foam isn’t easily removable. And even though its application is very simple, it can be hard to remove excess foam after curing and expanding. This is because you’ll have to sand it.

Nevertheless, you can remove expanding foam that has not cured and is still moist and soft using a solvent. And when you try to clean uncured foam remains with a non-solvent mixture it is likely to cure it Instead of making it clean.

How Can You Wipeout Expanding Form Using a Solvent

Clear Residue With a Putty Knife

You can remove the form residue with a plastic knife alongside a dry soft fabric.

Dampen Another Cloth With Acetone

This will help you clean the foam residue lightly. Ensure you apply force as necessary and wipe the surface using a circular movement. Also, consider re-dampening the material with acetone as required.

Clear Acetone Residue Using a Fabric Moistened with water

Wipe out all the foam residue before you even apply the water. And you’ll be done.


While there are several ways that you can use to fill up an opening around a gas tube, expanding spray foam is always a great solution. It will seal the gap just as you desire and I bet you won’t regret using it.

However, ensure you are so cautious while using it to avoid fire outbreaks that may arise due to the flammable gas in the foam.