Blueboard is a type of drywall or plasterboard sheet that is approximately 7.5 mm thick that is used to line the external walls of a building as a type of cladding. It is typically nailed or fixed to a timber or steel frame which provides the structural support. It is named after the blue-coloured paper covering, which serves as plaster or renders adhere. It's made from two thick sheets of paper sandwiched between a layer of gypsum and another sheet of paper to create it.
The acoustic ceiling tiles are installed on a light-blue board. It's a type of drywall plaster that can protect against scrapes and dents when used alone. Blue board may also conceal seams or joints between wall panels. It's not waterproof or water-resistant, so it could potentially be destroyed to do this. Builders appreciate working with it since it is lightweight, quick to install, and only needs plaster and tape on the seams instead of joint compound.