Firstly, they come in two types: Venting – which can open or Fixed – which can’t. Secondly, you don’t usually need planning permission to install a skylight – which is good news!
Skylights can come in a huge range of sizes, however if you opt for a larger skylight, but this will mean that the installer may need to cut one or more the rafters in your roof. This is perfectly ok for conventionally framed roofs. HOWEVER, a truss style is engineered to carry load, cutting the roof members could affect the structural integrity of the roof.
Skylights are available in different materials; however we do suggest that you chose glass. This may be the more expensive option, but it is much more durable than plastic and has often been made specifically to offer more strength and resistance to UV rays. Plastic must be coated in a special film to protect against UV rays, but it doesn’t stop the plastic from potentially warping.