injected spray foam insulation

Injected polyurethane foam

Synthesia Internacional is a manufacturer of polyurethane systems for construction and industry. The best known polyurethane applications are by projection (projected polyurethane or spray foam) and by injection.

Polyurethane systems are the result of the reaction between two chemical components. Polyurethane is a versatile material with countless applications. Today, we are going to talk about injected polyurethane in the construction sector: this polyurethane foam is applied in situ. The components are mixed directly on site and the result is injected through a series of cavities to the building element that we want to insulate. Once injected, the foam expands resulting in a rigid and durable insulation system.

injected polyurethane foam

Properties of injected polyurethane

Thermal insulation

The cell structure forming the polyurethane foam combined with the gas retained between these cells makes thermal conductivity of injected polyurethane be very low. Or, in other words, injected polyurethane is an optimal thermal insulation.

Acoustic insulation

Injected polyurethane contributes to reduce noise pollution. Low density injected polyurethane and open cell foams are the most suitable for acoustic insulation, and may have an absorption coefficient of up to α = 0.5.

This allows the injected polyurethane to be a solution against extreme noises. In this case, it increases the acoustic insulation of the building for frequencies between 7 and 9 dB, while dampening the vibrations produced by sound waves.

Waterproofing and moisture control

Closed cell injected polyurethane is one of the best materials to meet the degree of impermeability of façades established by regulations, the maximum requirement of protection by the regulations.

In addition, injected polyurethane also acts as a moisture regulating membrane, being at the same time water impermeable and vapor permeable. The degree of water vapor permeability can be reduced by increasing the density of the foam and the contents in closed cell, thus adapting to the climatic conditions of each building.

Behavior against fire

Although many people may think the opposite, polyurethane is safe in all its applications. The polyurethane insulation systems manufactured by Synthesia Internacional have obtained from Euroclass E to C, which certifies a range of good behavior against fire.

On the other hand, since the insulation is only one of the elements of a construction part- for example, of a facade – the reaction against fire of the constructive assembly will depend, among other factors, on the covering material that is applied


Thanks to its hygrothermal properties, injected polyurethane meets the requirements of legislation to guarantee indoor air quality inside buildings. Another great advantage in the field of health, compared to other insulators such as mineral wool, is that injected polyurethane does not release fibers, nor is it attractive to rodents, insects and other living beings that could damage the insulation.


In addition to the fact that its use contributes to reduce energy consumption in buildings, polyurethane waste can be reused as a load in high density panels. Moreover, the polyurethane systems made by Synthesia are free of CFCs and HCFCs, a clear indicator that they are 100% safe for the environment.

Mechanical resistance

Injected polyurethane has a high resistance against most chemicals. If we talk about materials used in construction, injected polyurethane supports most of the strong mineral acids and solvents used. It is also resistant to mildew and to the action of the roots, which makes it exceed the useful life of the building as it is a rot-proof material, stable against detritus, odorless and resistant even in the most aggressive industrial environment.


Adherence is one of the main competitive advantages of injected polyurethane compared to other insulating materials such as mineral wool, which can present settlements and detachments. Thanks to its physical properties, polyurethane foam completely adapts to the surface to be covered, creating a layer of continuous insulation, rigid and fully adhered to the walls of the element, without the need for auxiliary elements.

injected spray foam insulation


Injected polyurethane is easy to apply in areas with difficult access, which explains the rise of its use in the renovation of buildings that do not have any thermal insulation.

The most common application is the injection of polyurethane in the air chamber of facades: with a minimum of injection openings, the polyurethane foam accesses each corner of the air chamber, so that the wall is perfectly isolated and repaired. This function of “wall repairing” or stabilizer is due to the fact that polyurethane foam expands and gets into the cracks that have been caused over time.

Synthesia Internacional injected polyurethane systems

All the aforementioned characteristics make injected polyurethane systems an optimum solution for insulation, whether in new or in existing buildings. The Phono Spray I-905 System is an example of this.

Did you know that there are also different injected polyurethane systems for industrial applications?


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