I'm in an area of high radon and living in a pre-1980 house not designed or built with it in mind. Got tested for it and it was off the chart all over the house, so contacted a local company who ended up fitting 3 active sumps. This has brought the levels down to a fairly stable 30-35 bq/m3.
My question is, how realistic is it to get it below that figure by doing things like sealing floor cracks. I know that the floors in most of the rooms have cracks in them, but is it pointless if the areas underneath the internal walls are letting in gas. The guy who fit the sumps had a smoke device which demonstrated how the gas enters the room and I did notice that in a new bedroom with a modern well laid floor, plus a radon barrier and passive sump beneath it, the smoke was entering where the the floor met the wall.
I have read the reducing radon below 30bq/m3 is difficult in most circumstances so should I just leave well enough alone?
You could install a (hrv) heat recovery unit , and it will pump fresh air in and extract stale air out. Only problem its more suited to a well sealed house, but would help alot.