SPRAY FOAM INSULATION OR MINERAL WOOL?
Mineral wool insulation is less efficient than insulating foams, particularly at extremely low temperatures. The main reason consists in air tightness. Mineral wool regardless of the installation quality, it does not form air barrier and enables free air passage through its joints. The interior air and outside air, each with different temperature, thus meet in the vicinity of the insulation inside the building structure. Vapor starts to condense, which results in moisture formation within the insulation that you can hardly remove. Wet mineral wool loses its insulating properties.
When compared to mineral wool insulation, the undisputable benefit of the spray foam insulation consists in its joint-free technology which forms consistent thermal insulation layer.
COMPARISON OF MINERAL WOOL THERMAL INSULATION AND SPRAY FOAM INSULATION
Spray foam is a unique mixture of two compounds (compound A and compound B) which - when mixed under certain temperature and pressure - produce a mixture in which foaming agents form an immense number of small air bubbles. Thanks to the foaming agents, the substance also expands to 50 - 150 multiple of its original volume and hardens into the form of solid material. Depending on the formed cell structure, we then distinguish between open cell and closed cell structure foams.
SPRAY FOAM INSULATION TYPES
No two foam insulations are the same. There are great differences among them, open cell foams have completely different parameters and mainly serve for a different purpose. Closed cell insulating foams are characterized by high stiffness and it is capable of forming moisture stop and prevents water ingress starting from certain thickness. Spray foam with open cell structure is soft, open for diffusion, and allows water vapor / vapor to pass through. These characteristics of both foam types are substantial for understanding the difference between them and their different purposes. The open cell foam should in no way be used at wet spots and it may not get into contact with water - this foam type is intended for dry interior environment.
ENERGY EFFICIENCY OF SPRAY FOAM VS. MINERAL WOOL INSULATION
As previously described, the mineral wool is not capable of stopping the air flow. Premises insulated with mineral wool can have average heat loss 30% greater. Furthermore, if the mineral wool insulation has not been performed correctly (with gaps around light fittings, joints, beams, etc.), thermal bridges start forming and these result in even greater heat losses and moisture condensation. On the other hand, the foam insulation completely fills all gaps and prevents unwanted warm air escape.
Mineral wool insulation still belongs among the most commonly used thermal insulation methods in the Czech Republic. However, the indisputable benefits of spray foam insulations contribute to growing popularity of this modern thermal insulation method to the detriment of mineral wools.