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The details in this section have been developed for internally insulated cavity wall construction. The introduction document "Limiting Thermal Bridging and Air Infiltration Acceptable Construction Details" provides practical information with regards to implementation of these details onsite. This guide should be read in conjunction with these details.

Section 3 shows the use of internal insulation on masonry walls and is similar thermally to Section 6. It is not a typical construction method and is provided for information purposes only. As a result psi values have not been provided for the section and the y-value of 0.08 should not be claimed for these details as a stand alone construction. The appropriate psi values to be used are those provided for construction with internal insulation in section 6.

The details are indicative. They focus on the issues of thermal performance and air tightness. Other issues are not considered fully. Insulation thicknesses for the main building elements have not been provided, as these depend on the thermal properties of the material chosen, as well as on the desired Uvalue.

Masonry materials shown on the drawings are blocks and bricks. Other masonry materials, including precast and in-situ concrete, may be substituted without loss of thermal performance or increased technical risk. The use of thermally resistant materials, beyond that depicted, will naturally increase the thermal performance of the building fabric.

All materials and workmanship are to be installed to Technical Guidance Document D ‘Materials and Workmanship’.

Due to the practicalities of fixing insulated dry lining to blockwork, insulation should be installed in accordance with manufacturer's specifications.

All details are shown with a brick or block outer leaf for simplification. However other types of masonry materials may be used as a substitution, such as blockwork with render, precast and in-situ concrete, tile hanging or weather boarding without loss of thermal performance or increased technical risk. All external cladding systems should be proper materials as defined in Part D.

The suitability of full fill construction depends on the site exposure and nature of the outer leaf. Further information is given in BR 262 “ Thermal Insulation: Avoiding Risks” and relevant Irish Agrément Board certificates.

Technical Guidance Document B and Supplementary Guidance to TGD B provides guidance in relation to the provision of cavity barriers in air cavities, cavity barriers within combustible insulation layers and fire protection of structural elements.

These diagrams illustrate good practice for design and construction of interfaces only in respect to ensuring thermal performance and air barrier continuity. The guidance must be implemented with due regard to all other requirements imposed by Building Regulations.

The 2021 edition of the ACDs updates the drawings to take account of industry practice. The performance requirements remain the same as for the 2011 edition.

internal wall intro