Roof Ventilation Vital for Slate Longevity
Good ventilation is essential for slate. Moisture build-up under the slate will cause it to fret, crumble or de-laminate.
We have 120 year old Welsh slate at our warehouse that has been removed from a well ventilated roof and the slate is still sound and "rings true". This slate has years of working life ahead of it.
By comparison a similar aged Welsh slate laid on boards with no under-surface air movement is badly decayed and shows signs of delamination. We keep both as a demonstration of the importance of ventilation.