Heat rises, and an under-insulated roof space is the largest single escape route in most houses. Upgrading loft insulation is one of the cheapest ways to reduce heat loss, but it only works properly when the rest of the roof is set up to cope with it, which is exactly why we fit it alongside roofing work rather than treating it as an unrelated product.
The reason is simple. Better insulation makes the loft colder, because less heat leaks into it. A colder loft is more likely to see condensation forming on the underside of the roof unless the ventilation path at the eaves is open and working. Insulation stuffed tight into the eaves blocks that path, and the result is damp timber, wet insulation and mould in a roof that never leaked.
We survey the roof space, check the existing depth and condition, confirm ventilation and eaves detail, deal with any damp already present, and install insulation to a consistent depth with the ventilation path preserved. Where a re-roof, roofline renewal or repair is also happening, it is all handled by the same team on the same visit.