Hi there!, i really need some advice. I am converting my integral garage into a kitchen extension. The existing kitchen floor is a concrete base and the current garage floor needs raising to this level. My buiding regs officer says i need to insulate the new floor with kingspan, but i am really unsure of how to tackle it because the garage floor slopes down towards the up and over door. I was originally thinking of using leveling compound but then i thought of using timber joists and packing it up at one end, but the probem being the joist would only be about 30mm leaving about 18mm for a floor board...this would obviously bow when walked on. Has anyone got any advice of what i could do to get a smmoth transition between the existing floor and new floor.