There are lots of Kingspan insulated plasterboard thicknesses to choose from. We stock Kingspan Kooltherm K118 boards that range from 32.5mm to 72.5mm. The board that you should choose depends on the constraints of your project. You might need to choose a board that is thin enough to fit alongside a build-up of other materials. Other people just need the board itself to fulfil their project requirements. Always consult with a professional if you are unsure.