There are two things that home insurance is designed to protect. The structure of your home, the buildings and its contents. You can either have separate cover for each or combine both into one policy.
Buildings cover extends to the walls, windows, roof etc and also covers permanent fixtures and fittings such as baths, toilets and fitted kitchens.
A simple way to know which is which is to imagine you tipped your house upside down and shook it, what falls out would generally be considered as the contents