Lignacrete Block range

Lignacrete blocks are BSI Kitemarked and certified to BS EN 771-3. They are also Category 1 masonry units manufactured under a BSI certified Quality Management System, which is BS EN 9001 compliant.

Lignacrete blocks are medium grey to buff in colour. They are capable of being finished with all recognised treatments, including plaster, drylining and render, as well as cladding treatments. Paint Grade blocks can be directly painted.

Lignacrete can be considered for use in the following locations:

• The inner and outer leaves of external cavity walls
• Internal walls, including fire break walls
• Separating walls, including those conforming to Robust Detail party wall specifications
• Below ground
• Infill units to beam and block flooring
• Vertically reinforced walls – using hollow blocks

For walls that are to be directly decorated, Paint Grade blocks should be specified.

Specification & Application

Table Note:
(1) Airtightness results for painted walls are based on the use of Paint Grade blocks and standard emulsion paint.
(2) Hollow blocks are produced in 7.3 and 10.4N/mm² strengths.

Lignacrete blockwork provides excellent levels of sound insulation between buildings and adjoining rooms. It can be used in cavity and solid party wall constructions in dwellings, satisfying the specifications for dense blockwork in accordance with Building Regulations’ Approved Document E. It can also be used to construct party walls meeting Robust Detail specifications (e.g., Robust Details E-WM-1, 3, 16, 18 and 19). The Weighted Sound Reduction Index (Rw) values of various Lignacrete wall constructions are shown in Table 3.

Table 3 – Sound Reduction Values

Weighted Sound Reduction Index: Rw, (dB):

Lignacrete blockwork provides excellent levels of sound insulation between buildings and adjoining rooms. It can be used in cavity and solid party wall constructions in dwellings, satisfying the specifications for dense blockwork in accordance with Building Regulations’ Approved Document E. It can also be used to construct party walls meeting Robust Detail specifications (e.g., Robust Details E-WM-1, 3, 16, 18 and 19). The Weighted Sound Reduction Index (Rw) values of various Lignacrete wall constructions are shown in Table 3.

Where a higher level of sound insulation is required, Lignacrete blockwork can be used in conjunction with a number of acoustic lining treatments, installed to one or both sides of the wall. Blockwork of 100mm and 140mm thickness has been tested and has resulted in specifications that are capable of achieving in excess of 60 Rw (dB).

Table 4 – Lignacrete Wall with Acoustic Linings

The thermal resistance values (m² K/W) for Lignacrete blocks are shown in Table 5. For solid blocks, the values are calculated by dividing the block thickness by its thermal conductivity (W/mK).

Table 5 – Thermal Resistance Values

Presented in the tables below are the U-values for a range of wall constructions based on 100mm Lignacrete blocks with full and partial cavity insulation. The outer leaf is facing brick, but a rendered block outer leaf will usually achieve at least the same U-value.

Full Cavity Fill and 100mm Lignacrete Blocks

Partial Cavity Fill and 100mm Lignacrete Blocks

Our manufacturing plants operate to a BSI certified Environmental Management System (EMS), which complies with ISO 14001. Lignacite Ltd also meets the requirements of BES 6001 – Framework Standard for the Responsible Sourcing of Construction Products (Certificate No: BES 580823).

This independently awarded Responsible Sourcing Certification confirms that we procure products responsibly and sustainably. This will allow credits to be gained under environment assessment schemes such as BREEAM.

Lignacite Ltd operates a BSI Certified energy management system in accordance with ISO 50001. (Certificate No. ENMS 751020).

Compliance with ISO 50001 is a valuable tool in helping to manage energy use and includes the following outputs.

• A policy for more efficient use of energy
• Fix targets and objectives to meet the policy
• Use data to better understand and make decisions about energy use
• Measure the results
• Review how well the policy works, and
• Continually improve energy management

Key environmental performance data (in accordance with EN 15804+A2 and ISO 14025/ ISO 1930) can be found in the EPD for Lignacrete blocks.

Environmental Data Summary

Source – This data was taken from the EPD for the 7.3N Lignacrete solid block. EPDs for other Lignacrete blocks are available. Click here for all EPDs.

The declared unit is based on 1m² of 100mm thickness blocks.

The Life Cycle Stage (A1-A3) refers to the extraction, processing, transportation and manufacture of materials and products up to the point where they leave the factory gate to be taken to site.

The notation ‘e’ is an abbreviation for tonnes of carbon dioxide equivalent.

The design of walls using Lignacrete blocks should be in accordance with relevant design standards, including BS 8103: Part 2 and BS EN 1996-1-1 and the requirements of the Building Regulations.

Vertical movement joints should be considered in accordance with masonry design codes and the recommendations of Published Document PD 6697, at 6.0-8.0 metre spacings. In areas of raised stress, such as above and below openings in external walls, the blockwork may need to be reinforced to restrain movement.

When properly constructed, the durability of walls built using Lignacrete products will match that of walls of traditional masonry and will fulfil their intended function for the life of the building in which they have been installed (typically 100 years).

The blocks themselves will require no maintenance. Maintenance for walls will normally include the replacement of sealant in movement joints and at junctions / openings. Repointing for walls that are exposed to the elements may be necessary towards the end of its service life.

Under normal conditions, wall ties should be embedded 50mm into the mortar on each leaf, staggered in alternate courses and spaced in accordance with the following.

Table 6 – Wall Tie Spacings

Drylining

Standard plasterboard can be fixed with adhesive dabs or onto timber battens or metal studs.

Plaster

Dense plasters can be applied using either 1:1:6 cement:lime:sand or 1:4 ½ masonry cement:sand or 1:5 ½ cement:sand and plasticiser. It is advisable to use a bonding treatment prior to applying cement render plasters.

Lightweight plasters should be used in accordance with manufacturer’s recommendations. Suitable plasters include British Gypsum’s Thistle Carlite Bonding coat.

Finishing coats include British Gypsum’s Thistle Multi-Finish.

Rendering

It is advisable to apply a bonding treatment to the wall such as Rendaid. Traditional renders should be applied in 2 coats with the first coat applied to a greater thickness than the top coat. The first coat should be 8-12mm thick and the top coat 6-8mm. The first coat should be slightly stronger than the second coat. Render designation iii/M4 should be used e.g., 1:-1:5-6 cement, lime sand or 1:-4-5 masonry cement, sand.

Builders considering the use of proprietary render systems must exercise caution to accurately adhere to the render manufacturer’s design and specification instructions. Detailed guidance is also published in the NHBC Standards, Chapter 6.11- Render. Strictly adhere to the specific application instructions, paying particular attention to prevailing weather conditions and the minimum recommended thickness of single coat renders.

For detailed advice, refer to Lignacite’s Sitework Guide and the Material Safety Data sheet.

• Block packs may be stacked on firm and level surfaces to a maximum height of 2 packs. Consideration of handling equipment's suitability for site terrain and safety limits should also be given. Hand-operated pallet trucks may not be suitable unless pallets specific for this purpose are used and loads do not exceed the limits of the pallet truck or its operator(s). Care should be taken when opening packs that are wrapped or banded to ensure that items do not fall or otherwise endanger persons handling the blocks or those nearby.

• Handling of blocks should be undertaken in accordance with HSE Construction Sheet No. CIS77 ‘Preventing injury from handling heavy blocks’ (Construction Industry Advisory Committee) and in accordance with the Manual Handling Regulations 1992 (as amended). This concludes that there is a high risk of injury to individuals who repetitively manually handle blocks in excess of 20 kg. Where practical, mechanical handling equipment should be used to transport block packs to the area of work.

• Blocks should not be installed if the temperature is at or below 3°C and falling.

• Blocks should always be laid on a full bed of mortar and vertical joints solidly filled.
• For walls built fair, sample panels are recommended and should be built prior to commencing block laying. This will serve as a benchmark for defining and specifying the quality of work required.
• Please note that for Paint Grade products, colour consistency is not guaranteed. It is advisable to view sample panels at a distance of approximately 3m from the wall in good natural light.