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Fire Protection to Timber Floor Construction: Knauf C-Form-Soffit Lining CF5/13


Knauf C-Form suspended ceilings.

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+44 (0)1795 424499 www.knauf.co.uk

The Knauf C-Form Suspended Ceiling system uses the minimum number of different components and is extremely easy and quick to install. The system is strong, and suitable for larger ceiling areas.

The Knauf C-Form Suspended Ceiling system can provide up to two hours fire protection and easily accommodates changes in level.

Features and benefits:

  • Recommended for large ceiling areas and long spans.
  • Recommended when creating deep voids.
  • Strong, and resistant to movement.

To be installed in accordance with Knauf’s recommendations and British Standards BS 8212-1995 and BS 8000-8:1994.

The C Form Ceiling system has been designed based on ‘self-weight’ only basis, confirmation of any additional loadings would be required to ensure system performance.

The fire resistance performances are for imperforate ceilings incorporating boards with all joints taped and filled, or skimmed according to Knauf recommendations.

General information
Specification data
Product Reference

Fire Protection to Timber Floor Construction: Knauf C-Form Soffit Lining CF5/13

Suspension system -
Suspension hangers

Knauf Soffit Cleats fixed to Knauf Strap Hangers

Knauf 25 x 25 mm Angle Sections

Knauf Soffit Cleats with Knauf 25 x 25 mm Angle Sections

Knauf Universal Brackets


600 mm

900 mm

1000 mm

1200 mm

Upper support channel

Knauf ‘C’ Channels


600 mm

900 mm

1000 mm

1200 mm

Ceiling channels

Knauf ‘C’ Ceiling Channels


400 mm

450 mm

600 mm

Connecting clips

Knauf ‘C’ Connecting Clips

To be fixed at intersection between upper support Knauf ‘C’ Channel and lower ceiling Knauf ‘C’ Channels.

Lining -

One layer of 12.5 mm Knauf Fire Panel

Horizontal board joints

To be picked up Knauf Ceiling Channels

Lining fixings

Knauf Drywall screws at 230 mm centres, reduced to 150 mm at the ceiling perimeter

Perimeter Sealing

As per required interface detail to material abutment


Consult manufacturer and insert requirements.


Taped and Jointed for a Seamless finish using Knauf Jointing Products

Taped and skimmed with Knauf Finishing Plaster

Knauf RMF [Ready Mixed Finishing] in accordance with General clauses

Standard product features

Fire resistance (BS 476: Part 22):

30 minutes.

Suspension hangers:

1200 mm.

Upper channels:

1200 mm.

Lower channels:

450 mm.

System weight:

12 kg/m².

Fixings into substrates:

Fixings are used to meet performance constraint [confirmation is required from supplier to meet ceiling specification and any additional loading].

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