Bauschaum: Dangerous for the health?

PU foam has a reputation for being extremely harmful to one's health. Whether this is actually true, which substances in the construction foam are dangerous and which health risks can exist, read in this article.

Questionable ingredients

Ingredients in PU foam that may raise health concerns include:

  • isocyanates
  • MDI
  • diamines

Risks due to isocyanates and MDI

Isocyanates are considered potentially carcinogenic in science. Among the isocyanates, especially a substance is particularly dangerous - the MDI (methyldiphenyl isocyanate).

Concrete evidence for a carcinogenic effect of MDI does not yet exist. Only one animal experiment showed an increased cancer rate in the experimental animals when inhaled respirable MDI.

However, such respirable forms of isocyanates are no longer released into the air by construction foam once it is cured. The risk therefore exists only as long as the construction foam is not yet fully hardened.


Diamines are also suspected of causing cancer. Diamines can form when already cured building foam comes into contact with moist air. However, there is no concrete evidence of a risk of cancer, but only a scientific guess.

In practice, this risk is low because PU foam usually has not open contact with the ambient air. In this case, it would decompose by contact with UV light within a few days. Airtight completion of all joints would be a way to reduce such a risk - in practice, however, such a thing is hardly realizable.

Other health hazards

The only other danger that comes from PU foam is its highly irritating effect on the skin and mucous membranes. The effect is further enhanced by the high tack of PU foam, as it is usually difficult to remove from the skin.

However, simple protective measures already help:

  • Use of the construction foam only for the designated purposes
  • Always observe the manufacturer's safety guidelines
  • Use only in sufficiently ventilated rooms
  • Wearing long-sleeved clothing that covers the entire body
  • Safety glasses and protective mask

Tips & Tricks

Instead of using the gloves supplied with the package, use sturdy and well-protective gloves that are suitable for construction work.