A range of fine textured, medium density, load bearing blocks, suitable for facing and general purpose applications. The blocks consist of a specially formulated mix which reduces the block density producing a solid block under 20 kg unit weight.

The blockwork provides excellent levels of sound insulation between buildings and adjoining rooms. It can be used in cavity party wall constructions in dwellings, satisfying the specifications for lightweight blockwork in accordance with Building Regulations Approved Document E.

The blocks are medium grey in colour with a fine textured surface. Lignacite GP blocks have a scratched surface. There is a slight colour difference between the traditional block and this block. Lignacite GP has a striated face, providing an enhanced key for plastering and rendering. It is available in 100 and 140 mm solid form only.

Thermal bridging can be improved using approved junction details and PSI (Ψ) values, which can be accessed at www.cba-blocks.org.uk. U-values for wall constructions using Ash GP blocks to satisfy the requirements of Building Regulations Approved Document L can be found in Section 9 of Lignacite’s Design Guidance document (www.lignacite.co.uk, via the ‘Technical’ tab).

Features and benefits:

  • Good surface key for the direct application of plasters and renders.
  • For use internally and externally above and below ground.
  • High levels of air tightness, sound insulation and fire resistance.
  • Provide a strong background for holding fixings.
  • Over one-third of the materials come from sustainable sources.
  • Contains high quantities of graded wood particles.
  • 0.01 road miles associated with each metre of Ash GP produced.
  • Credits available under BREAAM and Code for Sustainable Homes.
  • CE marked to BS EN 771-1:2011.


Lignacite blocks are suitable for use in commercial and housing projects. Fair-Faced and Paint-Grade blocks can be used to construct internal walls in commercial, industrial and leisure buildings. The blocks can be used for the following:

  • The inner and outer leaves of external cavity walls.
  • Internal walls including fire break walls.
  • Separating walls including those conforming to Robust Detail specifications.
  • External and internal walls below ground (3.6 N/mm² blocks can be used in both inner leaf and internal walls; 7.3 N/mm² blocks to other locations).
  • Infill units to beam and block flooring.

The blocks can accommodate drylining, dense plaster, finishing coats and external rendering. Movement joints should be considered in accordance with PD 6697 at approximately 6 m spacings. In areas of concentrated stress, such as those above and below openings, consideration should be given to the use of bed joint masonry reinforcement.

The mortar type for work above ground level should be designation (iii) / Compressive Class M4. Stronger mixes may be used only with the permission of the designer. Stronger mixes may also be required for work below ground in accordance with PD 6697.

Related literature

The following content references this product:

Standard product features

Technical characteristics:

  • Face size: 440 x 215 mm.
  • Dimensional tolerances: Category: D1.
  • Net dry density: 1450 kg/m³.
  • Thermal conductivity: 0.47 W/m·K at 3% moisture content (Internal use). 0.51 at 5% moisture content (External use).
  • Moisture movement: <0.7 mm/m.
  • Reaction to fire: Class A1.
  • Configuration: Solid blocks: Group 1.
  • Specific heat capacity: 1000 J/kg/K.
  • Water vapour diffusion coefficient: 5/15 μ (Tabulated value from BS EN 1745).

NBS Specification

NBS Create logo
This product is associated with the following NBS Create clause:
45-80-50/300 Aggregate concrete blocks

Product specification

An important note about specifying



Lignacite Ltd


+44 (0)1842 810678

Product reference

Ash GP

Mean unit strength

[3.6 N/mm²]
[7.3 N/mm²]
[10.4 N/mm²]

Manufacturer details

Norfolk House,
High Street,
Suffolk, IP27 0AX
Tel +44 (0)1842 810678
Fax +44 (0)1842 814602
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