Extensions
If digging through solid floors may require you to move out temporarily Generalextensions http://www.simplifydiy.com/building-works/extensions
Building Regulations For Extensions
As is fashionable these days a conservatory added to extend a kitchen generally has no door or partition and is therefore falls into this category http://www.simplifydiy.com/building-regulations/extensions
Loft Conversions
Regulations permissions for extensions http://www.simplifydiy.com/building-works/extensions/loft-conversions