<span style="font-size: 10pt">Swedish prefabricators of domestic buildings need to become more effective and efficient; the aim of this paper is to investigate the usefulness of rule-based IT support tools for this purpose. The current sales and design process at a Swedish timber volume element prefabricator is presented. The process was mapped and the early design phase was evaluated regarding information management and standardisation. It was found that information management during early design is often ad hoc and person dependent; therefore searching for information that could lead to reuse of past solutions is rather time demanding. There is a need for standardisation to promote reuse due to a mentality of designing one-of-a-kind buildings. Knowledge-based engineering is seen as an enabler to enhance the current situation and an IT support approach is suggested. A demonstrator stair tool is tested, which lets the seller discuss needs with the customer and then use the tool to assess cost and manufacturability. If design flaws can be found early on, waste activities downstream can be reduced. Standardisation could be realised through modularisation, which the implementation of an IT support tool could gain from.</span>