Many building decisions will be taken away from you when planning your works extension. The architect will advise you on what designs will be allowed by your local planning and building regulation department. However, once the broad outline of the extension has been agreed there are many decisions to be made.

Within the extension tips section there is advice on...

Potential high costs that need to be considered and possibly avoided when you design your extension.
Other general tips and considerations when you design your building.
A comprehensive list of areas you need to consider for the building, electrical, joinery and plumbing in planning and designing your extension, so that you know all the decisions that you will need to make during the work. For example, ask your architect for advice on the size of the ceiling joists. If the correct size is fitted alterations and developments can be made in the future with minimal costs and work.