Hi All, we have a roof that's has the horrible spray foam insulation on the slate tiles. We Also have the traditional 50mm loft insulation and recently tried to get it upped to 270mm. The loft insulators refused to lay the additional insulation siting condensation and ventilation. Unfortunately wife was in the house at the time and let them leave. I have checked and the eaves are well ventilated into the loft space. Would it still be sensible to add additional insulation bearing in mind the sprat foam has a higher chance of rotting the timbers?