I've lived in two underpinned houses. The first was underpinned while we lived there. Done on our insurance. No problem selling it on, no hike in our insurance premium. The house we currently own was underpinned about ten years before we bought it. The only potential downside is that you are usually tied to the insurer who was insuring the property when the underpinning was done so you can't shop around. However, I recently checked with a specialist broker and he said our current premiums were no higher than normal market rates.