The paper discusses practical problems encountered during efforts to reduce radon concentrations in houses. The 10 problems identified represent only a few of the many daily problems encountered by diagnosticians and mitigators. Nonetheless, they are some of the current common problems that need to be considered and hopefully resolved in the near future. The 10 problems are: inconsistent sub-slab aggregate, hidden pathways to chimneys, variations in porosity of concrete/cinder block and block coatings, access to radon entry surfaces, diurnal/seasonal variation in radon concentrations, impact of radon-in-water on radon-in-air, sealing the top row of concrete blocks, insulating half-basements, sealing large thermal by-passes, and coping with direct rock exposure.