3mm Aluminium Sloping Coping – 2m Length | 100mm External Leg - Online Metal Store Ltd

3mm Aluminium Sloping Coping – 2m Length | 100mm External Leg

£121.21
(£145.45 Inc VAT)

3mm Aluminium Sloping Coping – 2m Length | 100mm External Leg

There is a straightforward reason why this product costs more than three times the price of the 2mm 1m equivalent. The 3mm gauge requires more material, it serves wider parapet walls in the 315mm to 865mm range, and it is specified for commercial buildings and exposed sites where the coping is expected to perform for 25 to 30 years without anyone going up to re-seal a joint or re-fix a bracket. On a commercial project, a housing development with an NHBC warranty requirement, or a parapet on a building near the Essex coast where the wind loading is real rather than theoretical, the 3mm specification is the right starting point, not an upgrade. The 2m length is the natural infill choice for medium commercial parapet faces, producing fewer joints than 1m sections and less waste than a 3m section on runs between 2m and 5m.

This is the 3mm aluminium sloping coping in a 2m length with a 100mm external leg. It is the commercial-grade companion to the 2mm 2m version in the same leg size and profile, with the heavier gauge and wider size range that commercial and exposed-site specifications require. Manufactured in Chelmsford, Essex, powder coated in any RAL colour, made to order and non-returnable unless faulty.

2mm or 3mm: Getting the Gauge Right Before You Order

This is the first question to settle because the 2mm and 3mm systems use different accessories, different brackets, and the sizing formula is the same but the size range is different. Here is how to decide:

Use 2mm Sloping Coping When

The project is a domestic flat roof extension, box dormer, garage or outbuilding in a sheltered residential setting. The parapet wall is a standard single-skin or modest cavity construction with an overall width below about 315mm, which keeps the coping girth below 510mm. The site is not exposed or elevated. Budget is a consideration and the specification does not require 3mm. The 2mm sloping coping 2m length and the 2mm 1m section cover this market.

Use 3mm Sloping Coping When

The project is commercial: office, retail, healthcare, light industrial or mixed use. The parapet wall is a cavity wall or wider construction that produces an overall coping girth of 510mm or above, which falls in the 3mm size range. The site is exposed, coastal, or elevated to a point where wind uplift at the parapet is meaningfully higher than at ground level. The NHBC specification or the structural engineer's notes call for 3mm. The building has two or more storeys. When any of these conditions apply, you need the 3mm system throughout: lengths, corners, stopends and brackets. The 5mm coping bracket is the correct fixing bracket for the 3mm system. Do not substitute the 4mm bracket, which is only for 2mm coping.

Product Overview

This 2m section is part of the Online Metal Store Ltd 3mm aluminium sloping coping system with a 100mm external leg, fabricated at the Chelmsford facility. At 3mm, the profile has greater cross-sectional rigidity than the 2mm equivalent, which means it holds its shape better under repeated thermal expansion and contraction on a fully exposed commercial parapet and resists the peel forces from wind pressure more effectively over a long service life. The built-in slope tilts toward the external face so rainwater drains off the surface and over the 100mm drip edge rather than sitting on the coping. The 23 available width sizes, from 510mm to 1060mm in 25mm steps, cover commercial parapet wall widths from approximately 315mm up to 865mm.

The 2m section works alongside the 3m length and the 1m length in the same 3mm 100mm system. On a commercial parapet run, plan the layout with 3m sections first for the long continuous spans, use 2m sections for the medium faces and infill positions, and bring in 1m sections only where the remaining run length genuinely requires a short piece. Every component in the system, including corners, stopends and the 5mm coping bracket, must be the correct 3mm gauge specification.

Key Benefits

3mm Gauge for the Demands of Commercial Parapets

At 3mm, this coping section is stiffer across its profile than the 2mm version. On a commercial building at any height, wind pressure acts on the coping overhang and generates a peel force at the fixing points. The 3mm gauge handles that force more effectively, which matters most on a building that will not be re-roofed or re-copiced for 30 years or more. On a domestic sheltered extension, 2mm is entirely appropriate. On a commercial building near the Thames Estuary or on an open site in north Essex, 3mm is the right call.

2m Sections for Fewer Joints on Commercial Runs

Every joint on a commercial parapet run is a sealant line. A properly sealed joint on a well-installed system is perfectly weathertight, but it is also a position that a facilities manager may need to inspect at some point in the building lifetime. On a 20-metre commercial parapet run, planning the layout with 3m and 2m sections rather than shorter lengths reduces the total joint count and keeps the maintenance position as simple as possible. A 4m parapet face served by two 2m sections has one joint; served by four 1m sections it has three.

Built-In Slope for Positive Drainage on Any Elevation

The slope in the coping profile tilts the top surface toward the external face, so water runs off the coping rather than sitting on it. On a south-west-facing commercial parapet in the South East, this is not an academic point: sustained driving rain in winter months can deposit substantial volumes of water on a coping surface, and a slope that carries it over the drip edge and away from the wall face is doing useful work every time it rains.

23 Commercial Width Sizes from 510mm to 1060mm

The size range maps directly onto commercial parapet wall construction. A 510mm size serves a parapet wall of approximately 315mm wide, which is the sort of wall width you see on commercial cavity construction or insulated commercial parapets. The 1060mm top size covers an 865mm wide wall, which takes in wide commercial structural parapets. If your parapet wall produces a coping girth below 510mm, your wall is likely within the domestic range and the 2mm system is probably the right product. If it exceeds 1060mm, contact Online Metal Store Ltd to discuss a bespoke solution.

Powder Coated in Any RAL Colour

Every component in the 3mm sloping coping range is finished with an external grade polyester powder coat in any RAL colour. Ordering the 2m sections alongside the 1m sections, 3m sections, corners, stopends and brackets in the same RAL at the same time means all components go through the same coating batch at Chelmsford and arrive on site colour-matched throughout the system.

Made in Chelmsford, Fast UK Lead Times

Made to order at the Online Metal Store Ltd facility in Chelmsford, Essex. As with all components in this range, this is a custom-fabricated product and is non-returnable unless faulty. The size calculation below is essential before ordering: measure the wall width, apply the formula, and check the result against the available sizes before placing the order.

Technical Specifications

Material: 3mm grade aluminium

Profile: Sloping coping length

Length: 2m (2000mm)

External Leg: 100mm

Internal Leg: 75mm

Width Sizes Available: 510mm, 535mm, 560mm, 585mm, 610mm, 635mm, 660mm, 685mm, 710mm, 735mm, 760mm, 785mm, 810mm, 835mm, 860mm, 885mm, 910mm, 935mm, 960mm, 985mm, 1010mm, 1035mm, 1060mm (23 sizes in 25mm increments)

Wall Width Range Served: Approximately 315mm to 865mm (wall width + 195mm = coping size)

Size Note: The "size" refers to the overall WIDTH of the coping profile, not the run length. All sections on this page are 2m long. The size you select determines the girth to match your wall width.

Finish: Polyester powder coating, external grade

Colour: Any RAL colour to order

Compatible Bracket: 5mm Aluminium Coping Bracket -- NOT the 4mm bracket, which is for 2mm coping only

Fabrication: Made to order -- non-returnable unless faulty

Country of Manufacture: United Kingdom (Chelmsford, Essex)

Calculating the Correct Width Size

The 23 sizes from 510mm to 1060mm are coping widths, not run lengths. Every section on this page is 2m long. The formula is the same as for the 2mm 100mm system:

  • Measure the parapet wall width at the top, from outside face to inside face.

  • Add the external leg (100mm) and internal leg (75mm) = 175mm.

  • Add both 10mm returns = 20mm.

  • Total: wall width + 195mm = the size to order. A 315mm commercial parapet wall gives 510mm, the smallest available size. A 415mm wall gives 610mm. A 540mm wall gives 735mm.

  • If the calculated size falls below 510mm, the parapet wall is likely in the domestic range and the 2mm sloping coping system is the more appropriate product.

  • If the result falls between two available sizes, order the next size up.

  • Quickest site check: measure the overall width of an installed 3mm coping section or bracket across the full profile. That measurement is the size to order.

The Right Bracket: 5mm, Not 4mm

The 5mm aluminium coping bracket is the correct fixing bracket for all 3mm coping systems. The 4mm bracket is for 2mm coping only. Using a 4mm bracket on a 3mm commercial installation is an under-specification: the 5mm bracket is heavier, provides greater fixing resistance, and is the appropriate choice for the commercial and exposed-site conditions where 3mm coping is typically used. Fix brackets at maximum 1000mm centres on standard commercial applications. On exposed sites or elevated buildings, reduce centres to 750mm or as specified by the structural engineer where wind loading calculations have been carried out.

How to Install 3mm Sloping Coping 2m Sections

Mark the bracket positions along the full run before fixing anything. Fix the 5mm coping brackets at the confirmed centres, with a bracket within 150-200mm of every run terminal, corner junction and stopend position. For a 2m section, you need a minimum of three brackets: one near each end and at least one intermediate at around 1000mm from one end. Confirm all brackets are flat to the wall top and properly aligned before pressing any coping into place.

Press the 3mm coping sections onto the brackets working from the fixed terminal end of the run. Apply a continuous bead of colour coded sealant in the matching RAL colour to the internal face of each joint before butting the next section up. The sealant bead at each joint is the weathertight seal between adjacent sections. On a commercial parapet, work along the run systematically and do not move ahead of the sealant application.

Lock the coping to the brackets using colour coded metal fasteners in the matching RAL colour. Use metal fasteners on commercial substrate constructions rather than timber fixings. Fit the 3mm left and right handed closed stopends at the run terminals and the appropriate 3mm corner pieces at every change of direction. Apply a neat finishing sealant bead on all external joint faces.

Where the 3mm 2m Sloping Coping Section Is Used

Medium Faces on Commercial Flat Roof Parapets

Commercial buildings with perimeter parapets rarely have all faces of equal length, and not every face divides neatly into 3m sections. A 4m parapet face on an office or retail unit takes two 2m sections with one joint and no waste. A 5m face takes two 2m sections and a 1m cut, or a 3m section and a 2m section with one joint. The 2m section fills the gap between what the 3m length covers efficiently and what the 1m section is reserved for. On a commercial project, planning the run layout before ordering, with 3m lengths as the primary section and 2m lengths as infill, gives the most economical outcome on a made-to-order product at this price point.

NHBC New-Build Housing with Wider Cavity Parapets

On NHBC-registered housing developments where the house type specification calls for 3mm sloping coping on cavity wall parapets, 2m sections are typically ordered alongside 3m lengths to handle the medium-length parapet faces on each unit. On a development of 20 or more plots where the same house type repeats, reducing the number of offcuts and waste sections per plot through careful length planning saves money across the full order. The aluminium sloped coping case study shows the sloping coping system in use on a real residential development in London, demonstrating the quality of finish that a well-planned installation achieves.

Exposed and Coastal Site Parapets

Buildings on open-aspect sites in Essex, Suffolk and Kent, and particularly buildings within a few kilometres of the coastline, need coping that will stand up to higher wind speeds and the sustained salt-laden moisture that coastal air brings. The 3mm gauge is the correct specification for these sites, and the 2m section is the right infill choice on medium parapet faces within a predominantly 3m installation. Get the bracket centres right, use the 5mm bracket at 750mm centres or as engineered on exposed sites, seal every joint properly with colour coded sealant, and the coping will perform without attention for the life of the building.

Commercial Replacement and Refurbishment

When existing 3mm sloping coping fails or degrades on a commercial building, the replacement must be 3mm gauge. A 2mm replacement on a 3mm installation creates a profile mismatch at every junction between old and new sections, and the lighter gauge is under-specified for a site that was correctly assessed as requiring 3mm in the first place. The 2m section in the 3mm 100mm system is the right replacement length for medium parapet faces, with the matching corners, stopends and 5mm brackets all available from the same Chelmsford source.

Frequently Asked Questions

When should I use 3mm sloping coping rather than 2mm?

Use 3mm when the project is commercial, when the site is exposed or coastal, when the structural or NHBC specification requires it, or when the parapet wall width puts the coping girth at 510mm or above. If the coping girth falls below 510mm, your wall is likely in the domestic range and the 2mm sloping coping system is probably the correct product. The price difference is substantial, which reflects the material and specification difference between the two gauges.

How do I work out the correct size for the 3mm 100mm system?

Wall width + 195mm = the size to order. That accounts for the 100mm external leg, 75mm internal leg and 10mm returns each side (100 + 75 + 10 + 10 = 195). A 315mm wide commercial parapet wall gives 510mm, the smallest available size. A 540mm wall gives 735mm. A 715mm wall gives 910mm. If the result falls between two sizes, order the next size up. The 23 available sizes all refer to coping widths, not run lengths. Every section on this page is 2m long regardless of the size selected.

What bracket do I need for the 3mm sloping coping system?

The 5mm aluminium coping bracket is the correct bracket for all 3mm coping. The 4mm bracket is for 2mm coping only. On standard commercial applications, fix the 5mm bracket at maximum 1000mm centres. On exposed sites or elevated buildings, reduce to 750mm centres or as confirmed by the structural engineer for the wind loading conditions at the site.

When is a 2m section the right choice rather than 1m or 3m?

Use the 2m section for parapet faces between 2m and 5m where it gives fewer joints than 1m sections and less waste than a 3m section. On a 4m face, two 2m sections give one joint and no waste. Use the 3m length for long continuous runs of 3m or more where the run divides reasonably into 3m sections. Use the 1m section for the final infill piece, genuinely short parapet sections, and tight-access positions.

Can I mix 3mm and 2mm components on the same installation?

No. The 2mm and 3mm profiles have different wall thicknesses, which means the dimensional interface between them at a corner or stopend junction will not be flush. All components on a 3mm installation, from lengths to corners to stopends, must be 3mm gauge. Getting the gauge right on every component is straightforward: if the coping lengths are 3mm, every accessory must be 3mm.

Is 3mm sloping coping suitable for NHBC new-build projects?

Yes. A 3mm aluminium sloping coping system with 5mm brackets correctly spaced and joints properly sealant-bedded is consistent with NHBC Standards Chapter 7.1 requirements for parapet wall construction on new-build housing. Where the house type specification calls for 3mm sloping coping, ordering the full system from a single UK manufacturer with a traceable specification supports the warranty position on completion.

Part of a Complete 3mm Sloping Coping System | 100mm External Leg

This 2m section is one of three run lengths in the 3mm aluminium sloping coping system with a 100mm external leg. A complete commercial installation needs lengths in the right mix, corner pieces at every change of direction, stopends at every terminal end, 5mm brackets at the correct centres, sealant at every joint, and metal fasteners on commercial substrates. Order everything from the same Chelmsford source for matching profiles, consistent colour and a system that fits together correctly on site. The full 3mm sloping coping system with 100mm external leg includes:

For the full sloping coping range across 2mm and 3mm gauges, visit the Aluminium Sloping Coping collection page and the Aluminium Copings overview page. For the 2mm equivalent of this product, see the 2mm sloping coping 2m length with 100mm external leg.

Standards and Compliance

Aluminium sloping coping on flat roof parapets in the UK is specified under BS 6229:2018 - Flat Roofs with Continuously Supported Flexible Waterproof Coverings. This standard covers parapet and edge detailing requirements for flat roofs, including coping specification, bracket fixing and joint sealing. A 3mm aluminium sloping coping system with 5mm brackets at the correct centres and sealant-bedded joints throughout is consistent with the weathertight parapet detailing requirements of this standard. On commercial projects where a structural engineer has been engaged, bracket centres should be confirmed against the wind loading specification.

The external grade polyester powder coat finish applied to all Online Metal Store Ltd 3mm sloping coping components meets the requirements of BS EN 12206-1 - Organic Coatings on Aluminium and Aluminium Alloys. On a commercial project where the coping specification forms part of a contract document, this standard provides a documented basis for the coating performance requirement across every component in the system.

For NHBC-registered new-build projects, Chapter 7.1 of the NHBC Standards sets out parapet wall and flat roof construction requirements. A 3mm aluminium sloping coping system with properly sized and correctly installed components throughout is consistent with these requirements on new-build completions where 3mm has been specified.

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Custom Fabricated Item

This is a custom-fabricated item made to your selected size and finish. Please double-check measurements before ordering. This product is non-returnable unless faulty, as explained in our Refund & Return Policy

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