Roofline Closure Brochure

External Wall Insulation Systems Roofline Closure Systems for PAS 2035 Projects

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Roofline Closure Systems

Roof Line Closure Systems Background In August 2024, the UK Government announced that Roofline Closure Systems could be used in PAS-compliant retrofit projects, subject to specific conditions and design principles. This decision by the Department for Energy Security and Net Zero marked the end of a four-year period during which these systems were prohibited in projects funded by public money or requiring a third-party warranty. PAS 2035:2019 stipulated that "metal or plastic cappings and trims shall not be used" at roof interfaces with eaves and verges, a restriction reiterated in PAS 2030:2023. The original ban stemmed from widespread industry failures linked to traditional verge trims, which had been used for the past 40 years. As a result, the only allowed method for protecting the top of external wall insulation, where the existing roof overhang was insufficient, involved extending the roofline - an approach that typically increased costs and complexity.

The Challenge In certain situations, such as with mid-terrace properties, extending a roof on its own is either impossible or highly impractical. This can lead to complications with neighboring property interfaces, aesthetics, planning approvals, rainwater drainage, and other issues. Prior to the recent policy change, these challenges often resulted in properties with inadequate roof overhangs being excluded from retrofit programs, as they were typically more complex and costly. Consequently, many households missed out on the benefits of essential insulation measures.

Industry Response The National Insulation Association (NIA), the Solid Wall Insulation Guarantee Agency (SWIGA), and the Insulated Render and Cladding Association (INCA) formed a working group to develop practical solutions for reintroducing appropriately designed closure systems. Collaborating with the Government, BSI, the Retrofit Standards Task Group, and Trustmark, the group established new Design Principles and an updated Weathering Guide, titled “External Wall Insulation Specification for Weathering and Thermal Bridge Control Guide, August 2024.” These documents outline how Roofline Closure Systems can be effectively incorporated into retrofit designs while meeting the compliance requirements of PAS 2030/2035.

Roofline Closure Systems

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Roof Line Closure Systems for PAS Projects Roofline Closure Systems have been approved by DESNZ specifically for PAS projects.

These systems are designed to offer versatile and robust protection for External Wall Insulation (EWI) systems, should a roofline extension not be an option.

Design Principles Roofline requirements vary significantly within a scheme or property, requiring multiple solutions. Since standard details cannot cover all scenarios, a set of Design Principles has been established.

These principles are a support tool for the roofline closure details documented in the External wall insulation specification for weathering and thermal bridge control guide 2022. It is recognised that the documented details are not exhaustive and therefore these principles are designed to be used to develop new Roofline closure solutions that comply with the PAS 2030 2019.

1. Redundancy of seals At least two lines of weathering protection are required.

Sealants shall not be employed to provide the primary barrier to water penetration.

Additional redundancy can be achieved with an additional trim or suitable membrane.

All joints must have a double seal to comply with the PAS requirements.

Protection afforded to the top of the EWI system must include a secondary waterproof membrane and/or flashing that tucks under the existing sarking felt.

Overhang must be appropriate for exposure zone, (40 mm moderate or sheltered exposure – 50 mm severe or very severe exposure) based on the BRE wind driven rain map in BR262 Thermal insulation: avoiding risks – Appendix A:WP2 / (publishing.service.gov.uk)

2. Gable-to-Eaves Junctions Must be achieved with overlapping, prefabricated units/connectors Site fabrication is not permissible though minor site trimming is permissible.

Any joints between the primary and secondary seal must be staggered by 100 mm.

Insulation to be maintained in corner of gable wall up to level of loft insulation as per Retrofit Designer requirements.

3. Gable Apexes Formation Must be formed using prefabricated elements Site bent flashing can be utilised however secondary lead/lead replacement flashing required over the apex.

Site-formed mitre joints using two separate profiles are not permissible.

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4. Jointing Pieces/Connectors Must incorporate an under- or over connector that extends min. 40 mm on each side of the joint.

Connectors must be sealed to both sections of the metal profile (roofline closure, etc) using proprietary sealing tapes or proprietary sealants that must extend for the full width of the trim. joints between the primary and secondary seal must be staggered by 100 mm.

5.Any Lead Flashing: If using lead as a solution the maximum length in a single piece should be 1200 mm and overlaps should follow best practice.

Ensure health and safety requirements are complied with Control of lead at work(Third edition) - Control of Lead at Work Regulations 2002 Approved Code of Practice and guidance(hse.gov.uk) If Lead replacement flashings are used, these should be securely fixed in accordance with the manufacturer’s recommendations.

Loft 6. or Soffit Roof Insulation / Roof Overhangs

A minimum 40 mm (50 mm for high exposure) is required, if less then trims/flashings should be embedded into the masonry, or below the cement pointing at verges and sealed.

Any joints between a primary and secondary layer of redundancy must be overlapped by a minimum 100 mm.

The sand and cement fillet should be replaced with a suitable flexible mortar.

7. Weathering Protection Details The installation of the weathering protection details must be separately included within the EWI system holder training that is provided to registered EWI installation contractors.

8. Minimal Thermal Resistance

In all cases there should be continuity of the roof insulation and the insulated roofline closure solution to provide a minimum “thermal resistance of 0.6m2K/W (and ensure no thermal bridging).

Important Note: Roofline closure details that do not meet the requirements above are not acceptable Underfloor Insulatio for use with any funded or private schemes.

Roofline Closure Systems

Second Line of Protection To enhance the protection of the EWI systems, our Roofline Closure Solutions incorporate a second line of defence through membranes or secondary flashings fully in line and compliant with the design principals detailed above.

Minimum Line of Protection Suitable Base Materials Minimum Aluminium specifications 1050A –Other higher grades are acceptable – 3000/5000.

Minimum Stainless-Steel specifications 304 –Other higher grades are acceptable –316.

Minimum Thickness 1.2 mm aluminium with a tolerance +/-10% to be used for trim widths up to 160 mm.

For trim widths over 160 mm or trims to be used in exposed areas, minimum 50 mm overhang from face of render system, 1.5 mm aluminium must be considered for added strength and stability.

Front face of roof flashing will now be a minimum of 40mm deep.

Coating Requirements Polyester Powder coated aluminium must have a minimum coating thickness of 40 microns to BS or Qualicoat standards and Powder Coaters must be BS or Qualicoat approved applicators.

Pre-coated aluminium must be polyester coated on both sides and the thickness must conform to EN 13523-1.

In areas exposed to severe wind driven rain (Zone 4 of BRE wind driven rain map) or directly facing the coast, a marine specification coating should be considered.

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Survey Conducting a comprehensive survey is essential to determine the suitability of the Roofline Closure System for each specific property.

Click here to download a copy of the survey - LINK Accurate measurement and documentation of the existing roof overhang are crucial as they determine the required specifications for the system. Additionally, assessing the substrate's condition is essential to ensure it can support the installation, especially when using grind-in flashings.

Survey & Criteria

Relevant Considerations

Determine compatibility with the existing roofline and substrate.

Existing Overhang

Ensure the overhang is uniform across both the eaves and the verge.

Rafter Positioning

Rafters may need to be enclosed, navigated around, or modified as necessary.

Substrate Condition

When considering grinding in, ensure the substrate is stable and can withstand the process without damage.

Existing Insulation & Potential Cold Bridging

Ensure continuity of roof insulation with each detail installation, maintaining a minimum thermal resistance of 0.6m²K/W to prevent cold bridging.

Corner Details

Confirm how the eaves and verge will intersect to ensure a cohesive and functional design.

Existing Features

Elements such as corbels and quoins will need to be considered, as they may prevent these details from being installed. This could necessitate site-specific designs in accordance with the Roofline Closure principles.

Ventilation

Roof ventilation must not be obstructed/restricted when installing Roof Closure Systems.

Roofline Closure Systems

Installation During installation, a checklist form must be completed to document how the Roofline Closure System principles are being adhered to. Photographic evidence of the various installation steps is also required, and this information must be submitted to apply for a project warranty.

DESNZ will be observing and monitoring installations that are using this newly introduced method – SPSenvirowall are fully supportive of DESNZ and the new measures and will provide what assistance we can to help all parties to ensure full compliance and to avoid any potential future issues.

To help support and guide installers with the latest updates to PAS, we offer a one-day PAS2035 & Refurbishment training course at our four branch locations. The all-new course can be viewed and booked online here: https://spsenvirowall.co.uk/training_course/

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Details 13 details have been agreed by PAS DESNZ for Roofline Closure installation.

The detailing shown is indicative and can be modified and updated within agreed parameters to suit specific project requirements.

Drawing Location Examples

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Benx Lonsdale Chambers Lonsdale Street Stoke-on-Trent Staffordshire T: 0845 519 8641 www.benx.co.uk