The laying of a laminate or hardwood floor in place of carpet results in more impact noise (footsteps, dropped items) travelling into the floor. These noises can quickly become an annoyance for downstairs neighbours, often without the upper property being aware of it.
In response to a growing number of complaints about noise from laminate flooring, the Scottish Executive, through the Department for Environment, Food & Rural Affairs (DEFRA), commissioned Napier University to undertake research to investigate the problem. The research A guide for noise Control from Laminate and Wooden Flooring shows that removal of carpet and underlay on a basic timber floor could result in a 21dB increase in sound transmission. The problem is proportionately worse in Scotland than in the rest of the UK due to the higher proportion of flatted properties (some 40%) and the higher proportion of properties with timber joist party floors.
The Scottish Government leaflet Noise - Guidance on Home Improvements includes information and advice on the effects of hard flooring.