Your loft is either lined or open such that you can see the whole structure. The latter is still the most common, although more and more people are undertaking loft conversions.
Unlined lofts
This is the insulation of the ceilings of the uppermost floor from above. If your loft space is not used except for water storage [...]

Lots of different types of materials can be used to cover a lean-to roof.
Conservatories, carports and covered ways are often covered with corrugated translucent plastic sheets which allow natural light through. They are easy to fix; light in weight, making them easy to lift and manoeuvre; and require a rela­tively small supporting framework. The sheets [...]

The timber rafters of most pitched roofs measure 100 x 50mm. On roofs less than about 30 years old, the rafters are covered with roofing felt a type called reinforced (it has a layer of hessian cloth bonded into it) comes in rolls 20m long by lm wide. The fell is usually fixed to the [...]

All roof faults should be attended to immediately they are noticed. If not, the damage to the fabric of the roof will rapidly get worse and worse, turning a minor repair into a major one. This is par­ticularly true for flat roofs.
The waterproof covering is usually three layers of bituminous felt laid on the roof [...]