house - single story or attic development

Hi,

I am at the very early stages of deciding on which type of house to build.I'm looking t havng between 200 and 250 square metres of floor space.My question is do I go for a smaller footprint and develope the attic into living space (probably making walls a little higher than normal) or do I make the house larger and have all living space on the ground floor.Any of you know which of these options is the cheaper one in general?

I would appreciate any,pitfalls comments or advice posted.

Thanks.

I would think that the one and a half story would be cheaper to build (less roof and foundation etc.) and cheaper to heat. It also leaves you with more garden space as the footprint is smaller.