Where and When to Use Expanding Foam

Expanding foam is a hugely useful tool for contractors with many potential uses. Primarily, it is great for closing gaps, helping to improve insulation for buildings.

Here at Fastbuild, we sell a range of building supplies in the UK, including expanding foam. Here, we look at its many potential uses to help you on your next job.

What is Expanding Foam?

Expanding foam is a substance made up of various chemicals, including polyurethane. It usually comes in a can, which is either:

  • Gun grade - to be used with a foam gun.
  • Handheld - comes with its own disposable nozzle.

As its name suggests, the chemical compound comes out of the can as a foam and then creates a reaction, causing the compound to expand. Some expanding foams can expand up to 30-60 times their liquid volume, although do check with the specifics of your product.

Types of Expanding Foam

Standard B3 expanding foam is the most common type of expanding foam. There are other types of foam on the market which act in similar ways but have different properties. An example is firestop - FR or B1 foam - which is fire rated.

When choosing an expanding foam, ensure you have the right product for your job.

Expanding Foam Tape

There are some other products on the market that have similar names to expanding foam. Examples of this include expanding foam tapes and expansion joint fillers.

Note that these products are very different to expanding foam in a can, and as such have other properties and uses not discussed here. Make sure you’re using the correct product for your project.

Expanding Foam Uses

Expanding foam is a hugely versatile product that is incredibly useful for construction. Here are some of the circumstances where expanding foam should be considered.

Filling Gaps

Buildings rely on a lot of large, solid components which can’t always connect fluidly. To ensure standards regarding insulation and moisture ingress are met, expanding foam can be used internally and externally to close small gaps.

Common instances where expanding foam could be used include:

  • Gaps around the edges of walls.
  • Filling holes made for pipes.

Window and Door Insulation

Insulation is hugely important for homeowners, keeping buildings warm during the winter while also reducing energy bills.

Windows and doors are often the primary culprits for heat loss. Expanding foam can be used to fill the gaps around window and door installations, helping to reduce heat loss in these areas and improve overall insulation.

Pipe Stabilising

Similar to windows and doors, plumbing is another feature that can leave small gaps. When installing plumbing, expanding foam can be used in holes to seal pipes in place, stopping any rattling.

Where Not to Use Expanding Foam

Expanding foam is not a miracle cure. While it is hugely useful, it should not be used to solve all problems.

One such example is electrical boxes. Expanding foam shouldn’t be used in these locations as it could cause jams that would be expensive to repair.

Likewise, expanding foam shouldn’t be used for structural repairs, as expanding foam doesn’t have the strength for these kinds of jobs. If there are cracks in masonry, these may need helical stitching bars.

Here at Fastbuild, we supply everything you need for your next job at unbeatable trade prices. Why not take a look at our range and see for yourself?

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