Polyurethane Roof Insulation
This method of roof insulation involves the professional spraying of a rigid http://www.simplifydiy.com/walls-and-ceilings/ceiling-insulation/roof-insulation
Loft Conversions
A loft conversion can add a considerable amount of floor space to your home but bear in mind that some of the walls and ceilings will usually be sloping to fit beneath the roof so you will not have full head height across the whole room http://www.simplifydiy.com/building-works/extensions/loft-conversions
SimplifyDIY Glossary: Q-R
A sloping roof beam usually timber forming the carcass of a roof http://www.simplifydiy.com/glossary/q-r