In this article
The aluminium skin rarely decides the U-value: the insulation and the brackets behind it do. Its fire class belongs to the product as tested, and above 15 m the whole build-up counts.
Five systems sold under one name
Industry guidance describes each of them[5][7][10].
| System | How it is built | Typical use |
|---|---|---|
| Profiled sheet | Roll-formed and self-supporting, used as a single skin or as the outer sheet of a built-up system [5] | Industrial walls and roofs |
| Standing seam | Long sheets on clips or halters, seamed by machine, mostly in aluminium [5] | Roofs, usually in long lengths to avoid end laps [5] |
| Rainscreen panels and cassettes | Water-shedding flat panels, planks or cassettes on brackets [5][7], with a cavity that can be ventilated and drained [7] | Architectural elevations |
| Composite panels (ACM) | Two aluminium sheets about 0.5 mm thick bonded to a lightweight core, 4 to 6 mm overall, the core depending on the fire classification [5] | Rainscreen |
| Fabrications and flashings | Cappings, fascias and bullnoses of 1 mm or more, flashings under 1 mm [10] | Edges and openings |
Insulated panels with an aluminium outer sheet exist too, especially as standing seam, but the usual skin of an insulated panel is coated steel[5]. When a drawing just says “aluminium cladding”, ask which of the five it means before pricing.
Fire: what TGD B 2024 asks of the wall
TGD B 2024, Volume 1, applies to works commencing on or after 1 May 2025, with transitional arrangements for some projects that had a planning application made or a fire safety certificate granted by 30 April 2025, tied to the external wall structure being erected by 30 April 2028 [1]. For any height or use, it asks for appropriate consideration in choosing external wall materials, and warns that combustible cladding framework, or combustible insulation used as over-cladding, may present a risk[1]. The detail then turns on the height of the topmost floor.
- Below 15 m, Table 19 applies to the outermost material. A single-storey building needs Class B-s3, d2 within 1 m of the relevant boundary and none beyond it. Multi-storey offices, shops, industrial and storage buildings need B-s3, d2 within 1 m and C-s3, d2 beyond[1].
- Above 15 m, the class applies to the whole wall build-up and to elements fixed to it: B-s3, d2 for offices, shops, industrial and storage buildings, A2-s3, d2 for flats, residential and assembly buildings. Insulation in drained or ventilated cavities should reach A2-s3, d2 or better[1].
Where products cannot meet Table 19, the route is a full-scale BS 8414 test assessed against BR 135, with the system built matching the system tested and certified as such[1]. Roof flashings, membranes, seals, fixings and window frames are among the items excluded from the over-15 m provision[1].
In a ventilated façade, compartmentation should be maintained to the inside face of the outermost element wherever a compartment wall or floor meets the external wall, and open-state cavity barriers are acceptable if appropriately tested[1]. Industry guidance treats site-installed fire stops and cavity barriers as part of every metal rainscreen[7]. Roofs are simpler: BROOF(t4) coverings are unrestricted, and TGD B gives that designation to pitched roofs of single- or double-skin aluminium profiled sheet[1].
Thermal: the aluminium is rarely the insulation
New walls in buildings other than dwellings should reach an area-weighted U-value of 0.21 W/m²K, with no part worse than 0.6, and new work on most walls in a material alteration 0.35[2]. These are backstops. TGD L says meeting the backstop levels will not on its own deliver the whole-building energy target, and its reference building assumes 0.18 W/m²K for walls[2].
In a rainscreen, the layers behind the water-shedding panel provide the insulation[7], and the brackets crossing them take some of it back. TGD L requires framing and other thermal bridging to be included in the U-value calculation[2], and aluminium brackets have to be isolated from cementitious backing walls, generally with thermal break pads[8]. Key junctions need Acceptable Construction Details, certified details or an assessed alternative, with site inspection[2].
An insulated panel can also carry the façade on its own or back a rainscreen[5]: a QuadCore KS1000 RW wall panel declares 0.20 W/m²K at a 91 mm core[11], and our guide to specifying Kingspan panels has the full table.
Durability, fixings and movement
Aluminium protects itself with an oxide layer that reforms when scratched, and BS 5427, as quoted by MCRMA, expects mill and stucco-embossed aluminium normally to last the design life of the building without maintenance[6]. Sheltered areas such as soffits, which rain does not wash, should be cleaned periodically[6]. Coatings, applied at 20 to 40 μm, are about appearance: typical minimum decorative lives run from 10 to 20 years depending on system and environment, against a design life of more than 40 years[6].
The risk sits at the contacts.
- Fasteners. A stainless fastener must be used with aluminium sheet. Carbon steel is acceptable only internally, in corrosivity categories C1 and C2[9].
- Supports. Where aluminium bears on galvanised steel spacers or rails, recommended practice is an adhesive barrier tape over the whole contact surface[9].
- Other materials. Keep aluminium away from ungalvanised steel, copper, mortar, alkali-bearing materials and fire-retardant treated timber, and on coastal sites from lead[6].
- Movement. Aluminium expands at 23.3 × 10⁻⁶ per °C, so fabrications on a floating fix are designed to about ±1 mm per metre with one fixed point per length[10]. Our parapet coping guide shows the slots.
- Brackets. Rainscreen fixings should be proven by pull-out tests on site, at least ten per fixing in each substrate, and masonry backing walls generally need more, around 5% of the anchors installed[8].
What the specification should say
- The system by type, and for a composite panel, its core.
- Purpose group, topmost floor height and boundary distance, with the Table 19 class and whether it covers the outer element or the whole build-up[1].
- Evidence for the product as built. Part D accepts CE marking, a European Technical Assessment or an Irish Agrément certificate as “proper materials”[3][4], and a BS 8414 test covers a system that cannot meet Table 19 product by product[1].
- A U-value calculation that includes the brackets[2].
- Coating, colour and site exposure[6].
- Fastener material, and isolation at every aluminium-to-steel contact[9].
- A movement strategy for fabrications[10] and the cavity barrier layout[1].
Where Clad-Primeco fits in
We install Kingspan insulated panel systems and the aluminium cladding details, copings and flashings that complete them, for main contractors, developers and public sector clients across Dublin and nationwide. Send the drawings and the fire strategy, and we will come back within 24 hours with a price or with the exact questions holding it.
Frequently asked questions
Is aluminium cladding non-combustible?
Not automatically. TGD B works with reaction-to-fire classifications, so the class of an aluminium cladding product depends on what it is made of. A composite panel’s class depends on its core, and differences in thickness, substrate, fixings or adhesive can change a rating. Ask for the declaration of performance. Where Class B is required, a product classified A2 or A1 also meets it.
Can aluminium cladding be used above 15 m in Ireland?
Yes, if the whole wall build-up meets Table 19 of TGD B 2024, which means A2-s3, d2 for flats, residential and assembly buildings and B-s3, d2 for most others, or if the complete system has passed a BS 8414 test assessed against BR 135 and is built as tested.
Is ACM banned in Ireland?
The 2026 edition of TGD B Volume 1 does not name ACM. It sets the class the external wall must reach by purpose group, height and boundary distance, and above 15 m that class covers the whole build-up. An ACM panel has to meet it like any other product, through its declared classification or a BS 8414 test of the system.
What fixings should be used with aluminium cladding?
Stainless steel, typically A2 (304) or A4 (316). MCRMA guidance requires a stainless fastener with aluminium sheet, rules out carbon steel except internally in corrosivity categories C1 and C2, and recommends an adhesive barrier tape wherever aluminium bears on galvanised steel.
Sources
- Department of Housing, Local Government and Heritage, Technical Guidance Document B 2024, Fire Safety, Volume 1: Buildings other than Dwelling Houses (2026 Edition)Accessed 2 November 2026
- Department of Housing, Local Government and Heritage, Technical Guidance Document L, Conservation of Fuel and Energy, Buildings other than Dwellings (2022)Accessed 2 November 2026
- S.I. No. 224 of 2013, Building Regulations (Part D Amendment) Regulations 2013, Part D, D1 and D3 (proper materials)Accessed 2 November 2026
- NSAI, Agrément CertificationAccessed 2 November 2026
- MCRMA GD39, Sustainability and durability of metal roofing and cladding systems, Section 7: Products (2022)Accessed 2 November 2026
- MCRMA GD39, Section 5: Metals, steel and aluminium (2022)Accessed 2 November 2026
- MCRMA GD34, The definition of cladding within the construction sector (2020)Accessed 2 November 2026
- MCRMA GD08, An introductory guide to rainscreen support systems (2013)Accessed 2 November 2026
- MCRMA GD33, Fasteners for metal roof and wall cladding: design, detailing and installation guide (2019, updated 2020)Accessed 2 November 2026
- MCRMA GD26, Aluminium fabrications: a guide to good practice (2020)Accessed 2 November 2026
- Kingspan, QuadCore KS1000 RW Wall Panel, product data sheet, Insulated Panels UK & IrelandAccessed 2 November 2026
