To divide a property into multiple units you must obtain planning permission. If the property is a listed building it is probable you will require listed building consent, and should therefore contact your local planning authority for advice before you start work. Works to a listed building that affect its special historic character without consent is a criminal offence.
When converting a house into flats it is important that you understand that you will need to comply with stringent sound insulation requirements. All dwellings for residential use must meet Document E sound regulations. This regulation states that the separating floor (floor between two separate dwellings) must achieve sound insulation figures of 43dB for airborne sound and 64dB for impact sound
Building Control will expect you to demonstrate compliance with Document E 2003 by undertaking an independent sound test to prove that you have met the standards for sound insulation. These sound tests must only be carried out by either UKAS or ANC approved Acousticians. If the sound tests are not carried out by approved Acousticians, then Building Control will not accept the sound test and it would need to be repeated at considerable expense.
In the case that the flat is in a conservation area and your proposal involves an element of demolition then you may need to apply for planning permission for relevant demolition in a conservation area and you should contact your local planning authority for advice.
The conversion can’t be signed off by the council until it has a successful sound test and failing to comply with sound test regulations can be extremely expensive.
At JCW we supply a range of soundproofing solutions suitable for meeting acoustic requirements when converting a property into flats. Call us on 01204 548 400 for more information.