I need a bit more ventilation in my loft without doing anything which will require building regs. The enclosed area is about 12 x 14 ft, and is in use for a model railway room. Local inspectors have frowned on similar usage near by and declared it to be habitable. Are there any window products or vents which can be fitted between the rafters without cutting into the structure (i.e. removeable if we sell the house). The rafters are at nominal
16 inch centres (they vary by as much as an inch.)TIA