When a test demonstrates that the sound insulation between new dwelling-houses, flats or rooms for residential purposes does not meet the performance requirements of Section 0 of Approved Document E, appropriate remedial treatment is needed. This Information Paper describes how to rectify faults that can cause the sound insulation to be lower than typically expected. Its advice is intended for developers, builders, designers, and others concerned with rectifying defects that cause poor sound insulation. 4 pages.