Renovation at the cottage and wondering if this is blåbetong? The root cellar seems to be constructed partly of some kind of concrete hollow block and then something more compact. Difficult to drill into, so there seems to be a lot of stone. I haven't drilled into the hollow blocks. Built in 1927. Are there Geiger counters available for rent, or companies that come out to measure? The cottage is in the forest in Västernorrland, so I guess there aren't many companies that check this in such a remote area, so the fastest solution is a radon puck and wait 3 months?
Blue concrete/lightweight concrete is really easy to drill into, so if it doesn't go easily with the drill, it's not lightweight concrete. Blue concrete is dark blue-gray. Very characteristic color. Unfortunately, color is difficult to judge on the computer screen, but the first image is questionably blue enough. Additionally, it looks like plaster, or is it painted directly on the blocks?