Thermal Liteblock – Roadstone solution to Part L

Thermal bridging is one of the key factors which need to be addressed for improved energy efficiency performance in the design and construction of new buildings. All thermal bridges must be minimised to reduce heat loss through cold bridging. All major junctions between building elements (floors, walls, roofs, windows and doors) must be built in compliance with the Acceptable Construction Details (ACDs).

Roadstone is proud to introduce the Thermal Liteblock system for use with traditional masonry wall construction. This system combines the Roadstone Thermal Liteblock with the Roadstone concrete block range, which when used in accordance with the Acceptable Construction Details (ACDs), achieves Psi values equal to or better than the standards set out in TGD Part L 2011.

Roadstone have thermally modeled all relevant details in appendix D of TGD L 2011. From this extensive research Roadstone are now in a position to provide detail solutions that comply fully with Psi value requirements outlined in TGD L 2011- Appendix D.

What is the Roadstone Thermal Liteblock?

Roadstone Thermal Liteblock is manufactured in Ireland, achieving Thermal conductivity (Lambda λ) values less than 0.33 W/mK, using a special mix which includes light weight aggregates. This mix produces a concrete block with excellent insulation properties, while maintaining structural strength and allowing for traditional construction methods to be used.



  • The Roadstone Thermal Liteblock is required only in key locations in conjunction with the Roadstone Concrete Block range (See Roadstone Standard Construction Details*).
  • The Roadstone Thermal Liteblock system is a very cost effective solution and can result in significant savings in the overall build cost.
  • Robust and durable concrete block with a minimum compressive strength of 7.5N/mm2.
  • Roadstone can provide Standard Construction Details* which are proven to comply with the Psi value requirements and facilitates ease of compliance with TGD L 2011.
  • Roadstone Thermal Liteblock is unique in colour to enable traceability on site. Photographic recording of the Thermal Liteblock built on site can then form evidence of compliance for the Assigned Certifier, Architects, Engineers and BER assessors.
  • Reduced Thermal Bridging resulting in reduced heat loss, and lower heating bills.
  • Excellent thermal conductivity (Lambda λ) value less than 0.33 W/mK for masonry block.
  • CE marked– manufactured to the requirements of I.S. EN 771-3 to System 2+.
  • Suits traditional construction methods familiar to Irish and UK designers and builders.
  • Roadstone Thermal Liteblock is a concrete block and provides excellent adhesive properties with traditional mortars and renders.
  • Improved (y) value calculations are achieved when using the Roadstone Thermal Liteblock system.
  • When a full building specific (y) value calculation is carried out using the Psi Values incorporating the Roadstone Thermal Liteblock, improved (y) value of between 0.03 and 0.06 can typically be achieved.
  • Compliant U-values are achieved without having to provide a cavity in excess of 150mm.


For further information or to receive a Technical Guide on Roadstone Thermal Liteblock please submit this Contact Us form.

Alternatively contact the Roadstone Head Office – 01 4041200 and a member of our Thermal Liteblock technical team will help with your enquiry.