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How to use expanding foam

How to use expanding foam

Posted on 15 November, 2021

Expanding foam is a popular product when sealing and insulating cracks. This can be particularly useful when remodelling homes or constructing new buildings. Expanding foam can be used in basements as well as doors or windows to prevent drafts, with its weather-resistant nature making it useful throughout the year. However, it is vital that you understand how best to apply expanding foam so there aren’t any major issues.

Clean the surface before starting

There are a few steps you should take before using expanding foam. Firstly, double-check the expiry date on the expanding foam. If you have just bought it, then it should be fine however if it is out of date then it will perform poorly or in very rare situations there is a risk of an explosion. Secondly, ensure that the area in which you are using the product is very clean. To do this, use a dry paintbrush to remove any dust or dirt. If you do not do this it could impact the effectiveness of the foam. The foam also needs moisture to expand and therefore it is a good idea to spray some water onto the area.

Be careful with expanding foam

Expanding foam can cause irritation to your skin and consequently, it is important that you wear gloves to protect your hands. You may also want to consider wearing a long-sleeved shirt or jumper, trousers and protective goggles or glasses. Windows should be opened to promote ventilation however if this is not possible you may prefer to wear a mask that can prevent you from breathing in the fumes. Shops tend to sell specific respiratory masks for this purpose.

Applying the foam

The surface should be moistened before applying the foam. After spraying the first layer of foam mist with more water and repeat this process to ensure that the foam hardens effectively. Then leave the foam to cure and this usually takes around an hour depending on the type of foam you have used. Make sure you read the instructions. After this remove any of the excess foam that is no longer needed. A hacksaw is a good option to do this. The final step required will be sanding the area so that you can plaster or paint over the foam.

Where shouldn’t you use expanding foam?

When attempting to remove drafts and improve insulation you may be tempted to use the foam around electrical sockets or lights. However, we would advise against this as when foam expands it could potentially find its way around the wires and create problems. For instance, lights can increase the chances of fires starting as if they radiate heat it could lead the foam to overheat.

Additionally, you will want to use the right type of expanding foam when working with windows. Low expansion foam will provide insulation whilst also allowing you to open and close your windows. Conversely, high expansion foam can expand and grow much larger and consequently, this can add pressure to the windows making them more difficult to open and close.

Finally, please consider where you are applying the expanding foam. It must be applied away from a spark or open flame. Some expanding foams contain compressed gas which can be highly volatile and explosive. As such, ensure that you don’t smoke or have your oven or stoves on when using the foam. Candles should be put out and windows can be opened so that fresh air can flow through easily and increase ventilation.

Will I need anything else when applying the foam?

Once you have removed the excess foam and sanded the area you may want to remove any foam that has accidentally become stuck to other parts of the wall or objects nearby. The foam is incredibly sticky and therefore the best option is to use a solvent such as acetone. For the best results use this when the product is still foamy.

Whether you are new to DIY or an experienced hand we have plenty of products and tools that can help you insulate your home or complete your project. Therefore, if you have any questions regarding expanding foam whether that be when or where here at BC Profiles we are happy to help and provide you with the answers.

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