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Additional storeys/Extending upwards

Building regulations: new internal elements

The new elements which help to form the new storey(s) are broadly:

  • Floor & beams
  • Walls
  • Doors


Floor & beams

A floor will need to provide structural support of the room’s contents and users and the weight of the floor itself.

It is unlikely that the existing ceiling joists will be adequate to support the weight (loads) that arise from the construction, contents and use of a typical upwards extension.

To overcome this problem new floor joists would need to be installed to take these new loads. These can normally be placed between the existing ceiling joists and will probably be larger than the existing joists. If the existing walls are adequate then the new floor joists may be supported on them.

Otherwise additional support – such as steel or timber beams – should be introduced which in turn will be required to be adequately supported and provided with fire resistance.


Walls

Walls will separate the new rooms from other areas of the home. These walls may need to be load bearing and/or fire resistant.


Sound insulation

Sound insulation is required between habitable rooms. With a terraced or semi-detached house, the building control body may also ask for sound insulation between the upwards extension and the neighbours loft to be improved. If they think it is necessary the building control body may also ask for a test to be carried out, but this will depend on the neighbours allowing access for the testers. The existing party wall will need to be upgraded to provide sound insulation between the properties.


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      The Planning Portal is delivered by PortalPlanQuest Limited which is a joint venture between TerraQuest Solutions Limited and the Department for Levelling Up, Housing and Communities (DLUHC). All content © 2024 Planning Portal.