If you are looking for ways un which you can expand the size of your home then you may consider extending your garage. If you have a garage attached to your house, you may quite easily be able to incorporate it in to your home to either add another room or enlarge an existing room such as a kitchen.
When it comes to extensions you first need to check if you require planning permission. If you do then you will need plans drawn up to show exactly how you are going to be extending the space. This will usually need the expertise of an architect.
Once you have obtained that you can start to get the building work underway. If you wish to build on top of the garage you will need to ensure that the foundations are deep enough to allow for that otherwise you may have to remove the garage and start the building work from scratch. This will cost more but does allow you the option to build on the top later on if needed.
You will need to decide how the front of the garage will look. It may be that you keep the front section as a garage still but incorporate the rea of the garage in to another room.