Polyurethane foam or expanding foam: what can it be used for?

If you often hear about polyurethane foam and you don’t really know what it is, or what it can be used for, here is a little post that can tell you more about it.

All about polyurethane foam

Also called expanding foam, polyurethane foam is a versatile product widely used by DIYers and various building craftsmen. It effectively allows caulking, gluing, fixing, soundproofing and insulating different materials such as plastics, bricks, concrete, metals and plaster. On the other hand, it does not adhere to glass, Teflon, polypropylene, silicone and polyethylene.

Even if it comes in liquid form, polyurethane foam becomes a semi-rigid foam and expands as it dries. This occurs when in contact with water or under the influence of air humidity. This is why it is often advisable to have a water sprayer handy when using this foam, which can be used to lightly dampen the target surface. This chemical reaction of expanding foam is called “polymerization”.

The expansive power of polyurethane foam is significant. To illustrate this, know that half a liter of this product in liquid form can give 20 liters of foam. In addition, this product offers high insulating power. 1 centimeter of foam is effectively equivalent to 40 meters of concrete. Given the important qualities of this product, it is more than necessary to use it wisely, in the right doses and with great care. To protect yourself from the projections of this foam during its application, for example, you must wear suitable goggles.

The main uses of polyurethane and expanding foam

Usually presented in the form of a 500 or 750 ml aerosol can with a multi-position or upward-facing valve, polyurethane foam can be used in construction and renovation, both indoors and outdoors. It can be used, among other things, to plug a pipe passage, to fill the remaining spaces of a window frame, to fill the grooves of electrical ducts, to seal the floor joists as well as to protect a roof from the wind.

It is recommended to use it when the temperature is between 10 and 30°C. And before any use, it is important to shake the container vigorously several times in a row in order to heat and homogenize its contents. At the time of application, the surface should be wetted with a little water. The valve must then be positioned at the target location. Keeping the head of the container down, you have to press lightly on the tip.

The cavity should not be completely filled as the foam will expand. Filling it halfway is more than enough. It is also better to proceed in small doses in order to judge the sufficient quantity. Even if it appears that the visible part of the foam is quite dry, it is better to wait 12 hours to make sure that the core is too. Finishing consists of cutting, coating and painting the foam.

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