AIM Soffit Liner Building Boards

AIM Soffit Liners offer excellent impact resistance and are used to provide an insulated external lining to soffits and an internal lining for walls and ceilings, especially where robustness is required.

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  • Mineral wool insulation backed boards 1200 x 600mm
  • Foam insulation backed boards 2400 x 1200mm
  • Manufactured from insulation slab bonded to fibre cement board, suitable for exposed and semi exposed applications
  • Available faced with UHD decorative rock fibre board, suitable for fully exposed exterior cladding
  • Surface of facing and Lamella rock wool insulation comply with Class O of the Building Regulations
  • High compressive strength
  • Thermal and acoustic insulation
  • Thermal conductivity of Lamella rock wool is 0.044 W/mK
  • Thermal conductivity of CRR Mineral Wool is 0.036 W/mK
  • Thermal conductivity of Extruded Polystyrene (80 > 120mm) is 0.034 W/mK
  • Thermal conductivity of Expanded Polystyrene is 0.038 W/mK
  • Thermal conductivity of Phenolic Foam is: 0>25mm 0.023 W/mK, 26>44mm 0.021 W/mK, 45mm+ 0.020 W/mK


Choice of Insulation

Compression Resistant Rockfibre (CPR)

High density acoustic grade resilient rock fibre insulation slab.

Extruded Polystyrene (XPS) 

Small closed cell extruded polystyrene for optimum insulation, high compressive strength and resistance to moisture.

Expanded Polystyrene (EPS)

Versatile expanded polystyrene for optimum value and light weight.

Phenolic (PHN)

Phenolic foam has very low thermal conductivity and excellent fire resisting properties (Class O).


AIM Speedline Soffit Liners may be fixed directly to concrete or masonry using suitable steel fasteners; the fixings supplier should be contacted for advice prior to installation, especially if a hard concrete has been specified.

Alternatively treated timber battens can be fixed to the concrete first and the AIM Soffit Liners then fixed to the battens. The battens should be fixed at 300mm centres for Compression Resistant Rockfibre and Lamella Soffit Liners or 400mm centres for XPS, Phenolic and EPS, running down the length. The battens must provide at least 75mm bearing.

The units are mechanically fixed to the battens by rust proof steel screws. The screws should be installed with a controllable speed screw gun and not overdriven, to prevent undue compression of the insulation backing.

Fixings are set in at least 50mm from the board edges, at the four corners of the board and at 600mm maximum centres. Lamella Soffit Liners must be fixed through the high density “ribs”, located at each end of the board and at the centre.

Where the AIM Speedline Soffit Liners are being attached to a framed backing, such as in the situation where they are being used to form a soffit under a trussed eave overhang, the framing must allow fixings at the centres specified above. Where this is not possible, or where there are problems with level alignment, a sub framing system needs to be used.


The facing of AIM Speedline Soffit Liners can be painted without any special priming using an alkali resistant paint or emulsion. Two coats of paint will usually give a satisfactory finish. Suitable paints are: Acrylics, Chlorinated rubber, Epoxy, PVA, PVC, Polyurethane and Silicate.

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