The paper describes a tool for generating plans for the construction of a building. The application is implemented in GCLA, together with a simple constraint solving system. The main idea is that experiences from other plans are stored in methods; which are a systematic way of grouping activities together as higher level activities that can solve more complex tasks. Activities are entities that perform some action on a model of the real world, called the global state. Activities have preconditions, i.e. starting conditions, some representation of time and resource consumption, and postconditions, i.e. how and what to change in the global state. Scheduling activities amounts to allocating resources and placing the activities in time. The goal of the planning process, i.e what we want the planning process to achieve, is represented by a geometric model of the changed global state, i.e. a design of the specified building that one wants to build. To create plans, the system is divided into two main phases; the choice-of-method phase and the scheduling phase. In the choice-of-method phase suitable methods are chosen based on experience from the past. Such methods already exists in the building industry, although not in an explicit formal representation. Then the scheduling phase allocates resources and places the activities in time by reasoning about the activities' change of the global state. The goal of the planning process is that the objects of the specified design should be produced and represented in the global state. The user can change most of the behaviour of the system by indicating what he wants it to do. He can change activities, their preconditions, calculations and postconditions, he can change methods, or add or remove activities to them, he can change resources etc. By this flexibility, the user can form his system to reflect his own preferences about how to plan and what to plan.