The hidden problems associated with spray foam insulation in roof spaces
Accurate inspections:
Spray foam creates a thick, continuous layer that completely obscures the underlying roof structure, including trusses, rafters, and sheathing. This makes it very difficult for surveyors to visually inspect the condition of the wood, identify cracks, rot, or other signs of damage. For example, if there is a roof leak behind the spray foam insulation, it many situation it would not be seen.
Trapped moisture and condensation:
Spray foam, particularly closed-cell varieties, can create a barrier that traps moisture within the roof cavity. This can lead to condensation buildup, especially during cold weather, potentially causing timber rot/decay, mould/mildrew growth, rust and corrosion with metal components and potentially structural issues
Ventilation issues:
Spray foam's ability to seal air leaks can come at a cost. It can also restrict proper ventilation in the roof space. This lack of airflow can further exacerbate moisture problems and contribute to:
Improper installation:
Applying spray foam correctly requires trained and certified professionals, as improper installation can significantly increase the risk of problems and cause difficulties for surveyors to evaluate properties. This includes overspraying, use of wrong spray foam types to even the thickness of the foam applied. Improper installation in turn can lead to uncontrolled condensation and damage to the roof.
Removal difficulties:
Removing spray foam, if necessary, is a complex and expensive process, often requiring specialised equipment and expertise. This can be a major drawback if you need to make repairs or modifications to your roof in the future.