GR 38 provides guidance to builders and homeowners carrying out installation works to reduce indoor radon levels in older homes. It describes the different construction features found in older properties and explains how commonly used radon remedial measures can be tailored to suit older buildings, including those that are listed buildings or located within conservation areas. This Good Repair Guide supplements the guidance given in Good Repair Guides 37/1, 37/2 and 37/3. Contents: Background Construction features and their impact upon radon solutions Other issues References