Soft foam insulation is preferred by contractors due to easier installation, its clean finished appearance, and less irritation compared to traditional fiberglass insulation. It is growing in popularity to for many residential and smaller commercial properties where its smaller diameter piping systems are more easily covered by foam.  Soft foam is substantially better as a covering for smallest diameter pipe fittings such as vent lines or drains.

However, soft foam insulation has significant drawbacks not immediately apparent, not well known, and certainly not advertised.  In many cases, it will produce far greater damage to cold water carrying pipe in comparison to fiberglass insulation – as this gallery demonstrates.

While the thickness and appearance of soft foam insulation would suggest superior resistance to moisture migration, moisture inevitably reaches the cold pipe surface.  Soft foam insulation naturally degrades over time; a problem accelerated by the higher temperatures of any hot water system.  Seam sealants offer varying levels of strength and weaken with age to produce extended separations of its edges.  As the material itself degrades, it becomes harder, less flexible, and more brittle – which then leads to shrinking and cracking.  The resulting cracks and openings then allow further moisture infiltration.  And when covered by vinyl, any indication to a problem becomes hidden view.

Furthermore, as the foam deteriorates its produces a weak acidic condition solution which further increases external pipe corrosion.  Opening soft foam insulation and finding it seemingly bonded to the pipe itself is a common indication to this even.  Whereas insulation failure generally has no corrosive impact against copper pipe, as it does for steel pipe, the production of acidic conditions by the degradation of soft foam insulation presents a significant threat to copper piping.