6.4 Timber and concrete upper floors

6.4.4 Fire spread

Adequate fire resistance and fire-stopping shall be provided by floors between homes and at penetrations. Upper floors shall be constructed to ensure structural timber is located away from heat sources.

Floors and ceilings should:

  • comply with the relevant building regulations and Technical Requirement R3
  • be in accordance with the design
  • have adequate fire-stopping
  • be able to resist the passage of smoke when the fire-stopping has been installed.

Timber

To counteract fire spread:

  • combustible material should be kept away from heat sources
  • structural timber should be separated from sources of heat in accordance with Chapter 6.8 ‘Fireplaces, chimneys and flues’.

Ancillary products

Where ceilings of intermediate floors in houses or compartment floors in flats/apartments are perforated or penetrated by services such as recessed light fittings (downlighters); ceiling-mounted air valves, vents and extractor fans and pipes, the floor construction should still achieve the required period of fire resistance.

When installing such ancillary products and/or services including their fire-stopping elements and intumescent seals used to maintain the fire resistance of the floor, one of the following should be met:

  • a satisfactory fire test evidence and/or extended field of application reports that support the use of such product/systems in the particular type of floor being considered, or
  • products and systems with a satisfactory assessment by an appropriate independent technical approvals authority accepted by NHBC covering the particular type of floor being considered, or
  • a proprietary floor system with satisfactory assessment by an appropriate independent technical approvals authority accepted by NHBC which includes the use of specific floor type and ancillary products which has been demonstrated to be satisfactory through testing and assessment, and are to be used within the limitations of the certification.

Last updated: 2nd January 2024

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