Does polyurethane foam insulation have a long service life?
Again, such statements cannot be called absolute.
First of all, only with polyurethane foam with a closed-cell structure can we talk about a long service life. Cheap open-pore paints that are applied from the outside and exposed to most common atmospheric moisture (even discounting the possibility of direct precipitation) are unlikely to last very long. In terms of hygroscopicity, they are no better than the same mineral wool, and talking about decades of operation is at least naive.
The most terrible enemy of polyurethane foam is the ultraviolet component of the solar spectrum .
Second, even with high-quality closed-cell polyurethane foam, the UV component of the solar spectrum will always result in a shortened service life. The material undergoes deconstruction, becomes brittle, brittle, and begins to succumb to wear and weathering. Even the highest quality polyurethane foam systems can lose up to 1mm in thickness per year due to exposure to sunlight. This is one of the disadvantages of polyurethane foam and must be taken into account when planning an insulation project.
Thirdly, the not very durable material may be due to incorrect proportions of components, violation of spraying techniques (this is often the mistake of many "offices" working in this field, such as the use of low-voltage equipment to apply the outer layer to the walls ). This again emphasizes the right choice of contractor.
But in general, if all necessary conditions are met, then we can safely say that polyurethane foam is indeed the champion among all wall insulation materials. The proof is in the demolition of old houses in Northern Europe that were 50 years old or more - where the polyurethane foam insulation remained intact and retained its essential qualities.