Expanding Foam 101 | How and When To Use Expanding Foam

Posted on 07/04/22

Using-Foam

Expanding foam is the ultimate tool for both trade professionals and DIY enthusiasts alike. Ideal for use on a variety of projects, expanding foam can make quick work of multiple jobs – from door installations, to filling gaps in the home as a barrier against insects and pests. However, though versatile, the product isn’t suitable for all projects, and can be messy and even dangerous if not used correctly. Here’s how and when to use expanding foam, so you can make the most of it year-round. 

What Can Expanding Foam Be Used For?

Packaged in a pressurised can, expanding foam is a liquid that has a thin straw applicator (or sometimes a nozzle) attached to its opening, enabling you to apply it into tight gaps and cracks. The foam expands almost immediately once released from the can, before hardening once dried. 

Commonly used for sealing gaps and holes that may present around pipes, expanding foam can also be used:

  • As a way of keeping your home more energy efficient by applying into cracks

  • As adhesive for outdoor landscaping projects

  • As a means of keeping pipes quiet if they knock when water flows

  • As a use for artificial flower arrangements.




Whatever your reason for using expanding foam, be sure to follow the manufacturer’s instructions and guidelines it comes with to ensure you’re kept safe.

How To Use Expanding Foam 
Here’s a step-by-step guide on how to using expanding foam: 

Step One

It’s important that the area is clean before using the foam, so first, use a large, dry paintbrush to sweep away any debris or dust in and around the space you’re working on. Once clean, spray the area lightly with water – the foam needs moisture to cure evenly, so a little water will help. 

Step Two

Before applying expanding foam, make sure you put on protective gloves – the product can be extremely irritant to skin, so gloves are essential. You should also use this time before application to read the manufacturer’s instructions. 

Step Three

Next, you’ll need to attach the nozzle or straw that comes with the can, before shaking the can thoroughly. Then, hold the can upside down and insert the nozzle or straw into the gap or area that needs to be filled. Carefully, apply the foam – remember that the foam will more than double in size once it has been applied. 

Step Four

As soon as you’ve applied the foam, use your water again to mist the area. If you’re applying multiple layers of expanding foam, you’ll need to apply water between each layer to help it adhere. Once done, leave the foam alone, giving it time to fully cure – this generally takes around an hour, but results will vary.

Step Five

Once the foam has fully cured and dried, you’ll need to trim off the excess. Using a hacksaw, carefully cut off any excess foam. 

Step Six

Finally, using sandpaper, sand down the foam to give it a smooth finish. The area is now ready to be plastered over or painted over if necessary. 


Some Handy, Helpful Tips 

Here’s some advice to follow when using expanding foam. 

Always…

  • Use a solvent to clean away any foam that spills or drips:

Expanding foam can be messy to use if not applied correctly, so it’s always a good idea to keep a solvent such as acetone nearby, to put on to a cloth to clean away any spillages as soon as they’re made. 

  • Check the expiry date of the product before use:

Expanding foam is a product that performs best when in date, so make sure the can you’re using is fresh and not expired. 

  • Clean the applicator properly after use:

If you don’t use an entire can of expanding foam, you can save the rest to use on a different project at a later date, but you need to ensure you clean the can and applicator properly before putting it away.  

  • Wear appropriate PPE:

Though expanding foam is non-toxic once cured, the product can both irritate the skin and release gases during the application process – these may cause symptoms for those who suffer from allergies or respiratory problems. Make sure you’re not only using the foam in a well-ventilated area, but that you’re also wearing the correct PPE (personal protective equipment) when doing so, such as long sleeves, gloves and protective eyewear. If you’re applying expanding foam in an area that isn’t well-ventilated, you should be wearing a mask. 

Never…

  • Use expanding foam near an open flame:

Until it’s fully cured, expanding foam is flammable, not to mention the compressed gas within the can itself being highly explosive, too. Be sure to never apply expanding foam while smoking or near any spark, and keep the entire can far away from open flames. 

  • Use expanding foam around outlets: 

Expanding foam enlarges very quickly once released and applied, and can therefore fast surround wires once it’s been distributed. This can not only be dangerous, but can also make rewiring jobs extremely difficult for you in the future.   

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