A portable classroom, (also known as a demountable or relocatable classroom), is a type of portable building installed at a school to temporarily and quickly provide additional classroom space where there is a shortage of capacity. They are designed so they may be removed once the capacity situation abates, whether by a permanent addition to the school, another school being opened in the area, or a reduction in student population. Such buildings would be installed much like a mobile home, with utilities often being attached to a main building to provide light and heat for the room. Portable classrooms may also be used if permanent classrooms are uninhabitable, such as after a fire or during a major refurbishment.