Wall Insulation: Insulating masonry cavity walls with internal dry lining

Internal block-work

Original plaster finish

Dry well adhesive

Plaster dabs

Mannok Therm Laminate-Kraft / MLK PIR insulation boards

Internal finish

Internal wall insulation is commonly used in existing buildings and in retrofit projects. The thermal performance of insulated cavity walls can be significantly improved by adding a layer of PIR insulation boards on the internal face of the walls. For masonry walls, the fixing method used will be dependent on the internal finish of the existing wall. In order for the wall insulation to be fitted correctly and achieve maximum performance, preparation of the internal surface is essential.

For walls with a very uneven surface, it is unlikely that dot and dab application of the insulation boards will be suitable, so using mechanical fixings will give the best result. This could include the fixing of timber battens on the wall surface to provide an even surface for the fixing of insulation.

For walls that are in good condition with an even surface, adhesive fixing of the wall insulation boards can be used.

For masonry surfaces with cracked or damaged plaster, it is important to ensure the damage is repaired prior to the installation of the internal insulation boards. For brick or block walls, pointing with mortar should be completed in order to prevent any air gaps and minimise thermal bridging issues.

All walls should be assessed to determine if they are suitable for dry lining prior to works commencing.

Mannok Therm Laminate-Kraft / MLK insulation boards are recommended for internal dry lining of masonry cavity walls. These high performance PIR insulation boards are faced on one side with a kraft paper facing which is suitable for adhesive or mechanical fixing methods, and plasterboard bonded on the other side to give a suitable internal wall finish.

How to install insulation in masonry cavity walls with internal dry lining

Installing the cavity wall insulation 

For new builds, the cavity wall insulation should be installed correctly according to the wall construction. Installation guides are available for cavity wall insulation:

Masonry cavity walls with partial fill insulation

Masonry cavity walls with full fill insulation

Insulating timber frame cavity walls

Insulating steel stud frame cavity walls

 

Installing internal dry lining insulation

1. Prepare the wall surface to ensure it is free from all obstructions. Remove skirting boards, picture rails and window boards, as well as any wall coverings with high vapour resistance, such as vinyl wallpaper or gloss paint.

2. Fit Mannok Therm Laminate-Kraft / MLK insulation boards against the inner leaf of masonry and hold in place using wall-tie clips or collars. Boards must be butted tightly together at corners to give a continuous layer of insulation and avoid thermal bridging issues. The insulation boards should be cut neatly to fit tight to the backs of frames, sills, cavity closers and lintels.

3. To minimise air infiltration, a continuous strip of dry-lining adhesive should be used to seal the perimeter of the Mannok Therm Laminate-Kraft / MLK boards, including around window and door openings.

4. For heavy fixtures such as wall cupboards or radiators, install timber fixing battens within the layer of insulation to carry them. Otherwise, the fixtures should be fixed directly to the masonry structure using appropriate mechanical fixings.

5. Fix Mannok Therm Laminate-Kraft / MLK insulated plasterboard to the wall with adhesive dabs and secure with 2 secondary mechanical fixings at mid height and at a minimum of 15mm from the board edge. The screws which fix Mannok Therm Laminate-Kraft / MLK to the battens should be selected to minimise heat loss: U-value calculations for the wall should account for the additional heat loss resulting from mechanical fasteners.

What thickness of insulation is required?

The thickness of wall insulation required will be dependent on the U-values you wish to achieve. Installing internal insulation impacts on the floor space of the internal rooms, so careful detailing can help minimise thickness of insulation to minimise the impact on floor space whilst achieving excellent thermal performance. See the below table for U-value results based on the wall construction shown. For project specific U-values use our free U-value calculator.

Required thickness of Mannok Therm Laminate-Kraft / MLK:

Cavity wall with internal drylining

Mannok Therm Laminate-Kraft / MLK Partial fill cavity insulation (mm)
50 60 75 80 100
Thickness (mm) U-value (W/m2K)
37.5 0.22 0.20 0.17 0.17 0.15
42.5 0.21 0.19 0.17 0.16 0.14
50.5 0.19 0.18 0.16 0.15 0.13
62.5 0.17 0.16 0.14 0.14 0.12
72.5 0.16 0.15 0.14 0.13 0.12
82.5 0.15 0.14 0.13 0.12 0.11
92.5 0.14 0.13 0.12 0.12 0.11

103mm brick outer leaf; 40 – 50mm low emissivity residual cavity; Mannok Therm Wall / MW; 100mm concrete block (conductivity as shown); 12mm plaster with dry wall adhesive; Mannok Therm Laminate-Kraft / MLK insulated plasterboard on plaster dabs. Calculations performed to BS EN ISO 6946, taking account of repeating thermal bridges.

Need technical support?

For help and advice on any of our products and how they might fit your needs please contact our Technical by Mannok team.

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  • Why Work with Mannok

    Why Work with Mannok

    At Mannok, we value the strength, skill and ingenuity of our workforce and we're committed to continual development and investment in our people to support every employee to achieve their career goals.

    We have a diverse culture, reflected not only in our business functions, but also in our people. A career with Mannok means joining a team that puts people at its core, whether it be customers, partners or employees. We offer significant development opportunities through a wide and varied range of roles and actively seek out potential.

    Mannok is an industry leader, with over 830 employees and almost 50 years of manufacturing history, supplying quality products to some of the construction and food packaging industries’ largest organisations.

    Sustainability sits at the heart of our values, as outlined in our 2030 Vision. We have ambitious targets which will see us transform from a carbon intensive business to a more sustainable pathway. In order to achieve our sustainability goals, we will rely on the commitment and support of every employee and seek to recruit those with shared values. We have built our vision on three core pillars of People, Planet and Partners, each of which are essential to the long-term success of our organisation, ensuring we continue to make a substantial contribution to the economic, social and environmental sustainability of this region for the next and future generations.

  • Benefits & Rewards

    Benefits & Rewards

    We value our people and give recognition for personal success, drive, commitment and determination. We understand that rewards are more than pay and performance related bonuses, so we have a variety of benefits to cater for the diverse needs of our people, these benefits include:

    • Attractive performance related pay scheme with annual salary review
    • Pension scheme
    • Life Assurance scheme
    • Sponsorship for professional qualifications / study leave
    • Enhanced company sick scheme
    • 30 days annual leave, inclusive of bank holidays
    • Incremental holiday allowance increase for long-term service
    • Skills Development Programme with structured career pathways linked to salary increments, rewarding multi-skilled personnel
    • Social Club
    • Discount on company products
    • Health & Wellbeing Programme
  • Professional Development

    Continuous Professional Development

    A career with Mannok offers a range of opportunities to continue learning and professional development, both internally as part of your role, and through our numerous educational and professional development partnerships.

    SKILLS DEVELOPMENT PROGRAMME

    We are changing how we develop, measure, and recognise levels of skills and competency in our business through the extension of our award-winning Skills Development Programme to every employee to enable all staff to become up-skilled and cross-skilled.

    The Programme will provide every employee with a structured development pathway and the necessary training materials to support their progression. Progress is linked to salary increases, ensuring our employees are financially rewarded for their skills and experience and are supported and encouraged to achieve their career goals.

    PROFESSIONAL QUALIFICATIONS

    At Mannok, we enable and encourage employees to progress their careers with recognised courses and qualifications in a wide range of disciplines through our range of development partnerships with some of the country’s leading educational and professional bodies. Employees have the opportunity to gain degree level qualifications and go on to become chartered in their relevant role.

  • Wellbeing

    Wellbeing & Resilience

    Here at Mannok, we recognise the importance of looking after our employees’ mental health and wellbeing, and that our duty of care goes beyond ensuring physical safety.

    We aim to create a diverse and inclusive workplace, enhance the mental and physical wellbeing of every Mannok team member and provide support to help sustain our people and build resilience into our business systems.

    We have established a partnership with local mental health charity, AWARE, and introduced a new Mental Health Charter to outline our commitment to the mental wellbeing of our employees. We have trained mental health first aiders across our business and all managers receive mental health training.

    Activities and advice on looking after your mental wellbeing are actively promoted through our internal communication channels and we provide signposting to support services available. Our digital employee health and wellbeing portal provides access to health, fitness and mindfulness classes and multiple resources to enable a tailored wellbeing platform for every Mannok team member.

Purpose

To benefit our local economy and community for the long term, providing sustainable employment opportunities and making a meaningful contribution to the economic, social and environmental prosperity of our local region.

Mission

To provide quality products and excellent customer service and to grow our business through continuous innovation, sustainability leadership and the development of our people. We are proud of our roots and are focused on the success of our local community.

Vision

To be sustainability leaders in our community and the industries in which we operate and the employer and supplier of choice.

Values

To be trustworthy
To respect people
To be committed to our community
To be sustainability leaders

  • Why Work with Mannok
  • Benefits & Rewards
  • Professional Development
  • Wellbeing
  • Why Work with Mannok

    Why Work with Mannok

    At Mannok, we value the strength, skill and ingenuity of our workforce and we're committed to continual development and investment in our people to support every employee to achieve their career goals.

    We have a diverse culture, reflected not only in our business functions, but also in our people. A career with Mannok means joining a team that puts people at its core, whether it be customers, partners or employees. We offer significant development opportunities through a wide and varied range of roles and actively seek out potential.

    Mannok is an industry leader, with over 830 employees and almost 50 years of manufacturing history, supplying quality products to some of the construction and food packaging industries’ largest organisations.

    Sustainability sits at the heart of our values, as outlined in our 2030 Vision. We have ambitious targets which will see us transform from a carbon intensive business to a more sustainable pathway. In order to achieve our sustainability goals, we will rely on the commitment and support of every employee and seek to recruit those with shared values. We have built our vision on three core pillars of People, Planet and Partners, each of which are essential to the long-term success of our organisation, ensuring we continue to make a substantial contribution to the economic, social and environmental sustainability of this region for the next and future generations.

  • Benefits & Rewards

    Benefits & Rewards

    We value our people and give recognition for personal success, drive, commitment and determination. We understand that rewards are more than pay and performance related bonuses, so we have a variety of benefits to cater for the diverse needs of our people, these benefits include:

    • Attractive performance related pay scheme with annual salary review
    • Pension scheme
    • Life Assurance scheme
    • Sponsorship for professional qualifications / study leave
    • Enhanced company sick scheme
    • 30 days annual leave, inclusive of bank holidays
    • Incremental holiday allowance increase for long-term service
    • Skills Development Programme with structured career pathways linked to salary increments, rewarding multi-skilled personnel
    • Social Club
    • Discount on company products
    • Health & Wellbeing Programme
  • Professional Development

    Continuous Professional Development

    A career with Mannok offers a range of opportunities to continue learning and professional development, both internally as part of your role, and through our numerous educational and professional development partnerships.

    SKILLS DEVELOPMENT PROGRAMME

    We are changing how we develop, measure, and recognise levels of skills and competency in our business through the extension of our award-winning Skills Development Programme to every employee to enable all staff to become up-skilled and cross-skilled.

    The Programme will provide every employee with a structured development pathway and the necessary training materials to support their progression. Progress is linked to salary increases, ensuring our employees are financially rewarded for their skills and experience and are supported and encouraged to achieve their career goals.

    PROFESSIONAL QUALIFICATIONS

    At Mannok, we enable and encourage employees to progress their careers with recognised courses and qualifications in a wide range of disciplines through our range of development partnerships with some of the country’s leading educational and professional bodies. Employees have the opportunity to gain degree level qualifications and go on to become chartered in their relevant role.

  • Wellbeing

    Wellbeing & Resilience

    Here at Mannok, we recognise the importance of looking after our employees’ mental health and wellbeing, and that our duty of care goes beyond ensuring physical safety.

    We aim to create a diverse and inclusive workplace, enhance the mental and physical wellbeing of every Mannok team member and provide support to help sustain our people and build resilience into our business systems.

    We have established a partnership with local mental health charity, AWARE, and introduced a new Mental Health Charter to outline our commitment to the mental wellbeing of our employees. We have trained mental health first aiders across our business and all managers receive mental health training.

    Activities and advice on looking after your mental wellbeing are actively promoted through our internal communication channels and we provide signposting to support services available. Our digital employee health and wellbeing portal provides access to health, fitness and mindfulness classes and multiple resources to enable a tailored wellbeing platform for every Mannok team member.