Never again have a problem finding reliable builders that will help you build a good house. Either it be a loft conversions or just a simple single storey house extensions. It is very important to have a good builders in your arsenal.
Extend your home in Barnet by starting finding an experienced local architect. Get an architectural consultancy, they will prepare the drawings and any planning permission.
A perfect solution if you space, as bungalows often sit on sizable plots. Extending a bungalow will be still possible even if it sits on a smaller piece of land.