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

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

£81.72
(£98.06 Inc VAT)

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

If you are ordering aluminium sloping coping for a flat roof extension, a box dormer, a garage parapet or a boundary wall, the 3m length is the right starting point. A 9m rear extension parapet takes three 3m sections with two joints and no waste. A 12m perimeter takes four sections with three joints. On any run of 3m or longer that does not leave an awkward infill gap, the 3m section gives you the fewest joints and the best use of material. Fewer joints means less sealant to apply, fewer potential failure points on a finished installation, and a cleaner continuous coping line across what is often a visible face of the building. Start with the 3m sections, calculate how many you need for the straight runs, and use 2m sections and 1m sections for any infill where the remaining run length does not divide neatly into 3m.

This is the 2mm aluminium sloping coping in a 3m length with a 100mm external leg. It is the primary run length in the domestic and light commercial sloping coping range from Online Metal Store Ltd, manufactured at the Chelmsford facility in Essex. Available powder coated in any RAL colour, in 29 width sizes from 185mm to 885mm, made to order and non-returnable unless faulty.

What Aluminium Sloping Coping Does, and Why It Matters

A parapet wall with no coping has an exposed top edge. Water sits on the masonry, works into the mortar joints with each frost cycle, and eventually finds its way down through the wall. Coping caps the wall and directs water away. Sloping coping does this with a built-in slope across the top surface that tilts toward the external face, so water runs off actively rather than sitting flat on the profile. On a domestic parapet in the South East, the combination of winter driving rain and frost cycles means proper surface drainage from the coping is a genuine long-term maintenance advantage.

The 100mm external leg overhangs the outside face of the wall by 100mm, carrying the drip point well clear of the wall face below. This prevents rainwater from running back down the wall surface, which over time causes staining, efflorescence on masonry, and surface degradation on rendered finishes. The concealed bracket system, using the 4mm aluminium coping bracket fixed to the wall top before the coping is installed, means the finished surface has no visible fixings, no holes in the aluminium, and a clean continuous profile across the full parapet run.

Key Benefits

3m Sections for Fewer Joints on Longer Runs

The 3m length reduces joint count compared with shorter sections on any parapet run of 3m or more. On a 15m perimeter run, five 3m sections give you four joints. Fifteen 1m sections give you fourteen. Each joint is a sealant application and a position that the installation has to get right. Reducing joints on long runs is good installation practice, not just a material economy, and the 3m length is where you achieve that.

Built-In Slope Sheds Water From the First Day

The slope in the coping profile is formed into the aluminium during fabrication, not applied afterwards. Every section arrives ready to drain, and once the system is installed and the joints are sealed, surface drainage from the coping requires no maintenance. On a south-west-facing parapet on a rear extension in Essex or East London, active surface drainage is doing real work every time it rains from the Atlantic.

100mm External Leg, Balanced for Domestic Walls

The 100mm overhang is the standard domestic specification for sloping coping across the UK. On a single-skin brick or block parapet wall of around 100mm to 200mm width, a 100mm external leg gives a proportionally correct profile, carries water clear of the wall face, and looks right against the parapet. For wider walls where a more substantial overhang is appropriate, the 125mm external leg system is available in the same 3m length from the same Chelmsford range.

Any RAL Colour, Consistent Across the System

The powder coat finish is an external grade polyester available in any RAL colour. Order the 3m sections in the same RAL as the 1m and 2m infill sections, corners, stopends and brackets, and all components are finished together in the same batch at Chelmsford. They arrive colour-matched. On a visible parapet where the colour has been chosen to match window frames, render colour or fascia boards, getting the batch right across every component is the only way to guarantee a consistent finish.

Made to Order in Chelmsford, Fast UK Lead Times

Every section is fabricated to the width and colour you specify at the Online Metal Store Ltd facility in Chelmsford, Essex. Made-to-order means non-returnable unless faulty, so measuring the wall width correctly and applying the sizing formula before placing the order matters. The UK manufacturing base keeps lead times short for projects across Essex, East London, the South East and the wider UK.

Technical Specifications

Material: 2mm grade aluminium

Profile: Sloping coping length

Length: 3m (3000mm)

External Leg: 100mm

Internal Leg: 75mm

Width Sizes Available: 185mm, 210mm, 235mm, 260mm, 285mm, 310mm, 335mm, 360mm, 385mm, 410mm, 435mm, 460mm, 485mm, 510mm, 535mm, 560mm, 585mm, 610mm, 635mm, 660mm, 685mm, 710mm, 735mm, 760mm, 785mm, 810mm, 835mm, 860mm, 885mm (29 sizes in 25mm increments)

Size Note: The "size" refers to the overall WIDTH of the coping profile, not the run length. All sections on this page are 3m long. The size you select must match the overall girth of your parapet wall.

Sizing Formula: Wall width + 195mm = size to order (100mm external leg + 75mm internal leg + 10mm + 10mm returns = 195mm)

Finish: Polyester powder coating, external grade

Colour: Any RAL colour to order

Compatible Bracket: 4mm Aluminium Coping Bracket (correct for 2mm coping system)

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

Country of Manufacture: United Kingdom (Chelmsford, Essex)

How to Measure: Calculating Your Width Size

The 29 size options from 185mm to 885mm refer to the WIDTH of the coping profile, not the run length. Every section on this page is 3m long. The size must match the overall girth of your parapet wall, calculated as follows:

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

  • Add 100mm (external leg) + 75mm (internal leg) + 10mm + 10mm (returns) = 195mm.

  • Total: wall width + 195mm = the size to order. A 190mm wide wall gives 385mm. A 265mm wide wall gives 460mm. A 340mm wide wall gives 535mm.

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

  • On site: measure across the top of any installed section of the same coping profile, from the tip of the external leg to the tip of the internal leg. That measurement is the size to order.

How Many 3m Sections Do You Need?

Work out the total linear metres of straight coping run for your project. Divide by 3 and round up to get the minimum number of 3m sections needed for the straight runs. Then plan for infill: any remaining section that falls between 0mm and 3000mm will need a cut from one section, or a combination of shorter lengths depending on how the run divides.

  • 6m parapet run: two 3m sections, one joint, no waste.

  • 9m run: three 3m sections, two joints, no waste.

  • 7m run: two 3m sections plus a 1m cut from a third section, or two 3m sections and one 1m section. Two joints minimum.

  • 4m run: one 3m section plus a 1m section. One joint. The 3m section is the primary piece; a 1m section handles the infill.

  • Multiple faces: add up the total linear metres across all faces, then plan each face separately. Corner pieces and stopends are ordered per corner and per run terminal, not per linear metre.

For short parapet sections under 3m, see the 2m length and 1m length pages for guidance on when each is the right choice. As a general principle: plan with 3m sections first, use 2m sections for medium infill between 1m and 3m, and use 1m sections only for short runs and final infill pieces.

How to Install 2mm Aluminium Sloping Coping

Mark the bracket positions along the full parapet run before fixing anything. Fix the 4mm aluminium coping brackets at the correct centres, not exceeding 1000mm, with brackets positioned within 150-200mm of every run terminal, corner junction and stopend. For a 3m section, you need a minimum of four brackets: one near each end and two intermediates at approximately 1000mm spacing. Confirm all brackets are flat to the wall top and properly aligned before pressing any coping into position.

Press the 3m coping sections onto the brackets from the fixed terminal end of the run. Before butting each section up to the previous one, apply a continuous bead of colour coded sealant in the matching RAL colour to the internal face of the joint. The sealant bead is the primary weathertight seal between adjacent sections. Keep the bead continuous with no gaps, and do not work ahead of the sealant application on longer runs.

Lock the coping to the brackets with colour coded fasteners in the matching RAL colour at the bracket positions. Fit the left and right handed closed stopends at the run terminals and the appropriate corner pieces at every change of direction. Apply a neat finishing bead of sealant on all external joint faces.

Where the 3m Sloping Coping Length Is Used

Domestic Flat Roof Extensions

The rear flat roof extension is the most common application for 2mm sloping coping in the UK. A single-storey extension behind a semi-detached or terraced house in Chelmsford, Brentwood, Basildon or anywhere across Essex and the South East typically has a parapet perimeter of 8m to 16m, the sort of run where three to five 3m sections form the backbone of the order. The aluminium sloped coping case study shows how the full system looks on a finished residential project in London.

Box Dormers

Box dormers on terraced and semi-detached houses across the South East commonly have a front parapet of 2m to 3.5m and two short side returns. A single 3m section covers the front face of most box dormers, either without cutting or with a short trim at one end. The two side returns are served by 1m sections. The result is a clean, low-joint installation that keeps the most visible face of the dormer looking right from the street.

Boundary Walls and Garden Structures

Low boundary walls, screen walls and garden structures with aluminium sloping coping are an increasingly common domestic application. On a garden wall with a straight run of 3m to 12m, the 3m section is the natural primary length. It gives a well-proportioned coping profile on a low wall, the slope keeps water clear of the wall face, and the long-term maintenance requirement is close to zero.

New-Build Housing Developments

On NHBC-registered new-build housing developments where the house type specification includes sloping coping on flat-roofed elements, the 3m length is typically ordered as the primary section for each plot or phase, with shorter sections for infill. Ordering the full system from a single UK manufacturer, from lengths through corners, stopends and the 4mm brackets, gives colour consistency across every plot and a traceable single-source specification for the installed coping. For developments specifying 3mm sloping coping, the 3mm sloping coping 3m length in the 100mm system is the commercial-grade counterpart.

Sloping or Flat Coping: Which Is Right for Your Project?

Aluminium Sloping Coping

The sloped profile actively drains rainwater off the external face. It gives a distinctive angled line at parapet level that suits residential architecture and is particularly common on domestic extensions across the South East. If the project calls for water to run off the coping visibly and positively, or if the building design benefits from a defined profile shadow line at parapet level, sloping is the right choice. The full range of lengths, corners, stopends and accessories for this system is available via the Aluminium Sloping Coping collection page.

Aluminium Flat Coping

The flat profile gives a clean horizontal line at parapet level, which is common on commercial buildings and contemporary domestic projects where a minimalist parapet detail is preferred. Flat coping relies on the external leg drip detail and correctly sealed joints for weathertightness rather than a surface slope. The 2mm aluminium flat coping range is available in the same 29 width sizes, the same RAL colour options and the same concealed bracket system. If the project calls for a horizontal profile, or if the existing coping on the building is flat and like-for-like replacement is required, flat coping is the correct choice.

Frequently Asked Questions

How many 3m sections do I need for my parapet?

Measure the total linear metres of straight parapet run, divide by 3, and round up to get the minimum number of 3m sections. If the total does not divide exactly into 3m, plan for the infill section separately: a 1m or 2m section for the remaining length, or a cut from the last 3m section if the infill is short. Do not forget to allow for the sections needed at each face of the parapet separately when the run has corners, as corner pieces do not contribute to the straight run length.

The product has 29 sizes. Are those 29 different run lengths?

No. Every section on this page is 3m long. The 29 sizes from 185mm to 885mm refer to the WIDTH of the coping profile, which is the overall girth from the external leg tip to the internal leg tip. The width you select must match the overall girth of your parapet wall: measure the wall width and add 195mm. For example, a 190mm wide parapet wall needs the 385mm size, and it arrives as a 3m long section that is 385mm wide across the top.

What brackets do I need for 2mm sloping coping?

The 4mm aluminium coping bracket is the correct bracket for the 2mm sloping coping system. Fix brackets at maximum 1000mm centres, with one within 150-200mm of each run terminal, corner junction and stopend position. For a 3m section, you need a minimum of four brackets. The 5mm bracket is for 3mm coping only and should not be substituted here.

Can I cut 3m sections to a shorter length on site?

Yes. Aluminium cuts cleanly with a fine-toothed hacksaw, a metal-cutting circular saw blade, or an angle grinder with an aluminium-rated disc. Cut square to the profile and file the cut edge smooth. On an exposed cut end that will be visible, fit a stopend rather than leaving the cut aluminium face open. Bear in mind that cut sections cannot be returned, so measure carefully before cutting and keep any offcuts that may be useful elsewhere on the job.

What is the difference between the 100mm and 125mm external leg versions?

The 100mm external leg is the standard domestic specification and suits parapet walls up to around 200-250mm wide. The 125mm leg gives a wider overhang, throws water further clear of the wall face, and produces a slightly more substantial profile at parapet level. It is commonly specified on cavity wall parapets and where the housebuilder or architectural specification calls for a wider overhang. The 125mm external leg 3m section is available from the same Chelmsford range. Accessories are not interchangeable between the two systems, so order all corners, stopends and brackets in the correct leg size for the lengths you are using.

Is this suitable for both new builds and refurbishment projects?

Yes. The 2mm aluminium sloping coping with a 100mm external leg is suitable for new build flat roof extensions, replacement coping on existing buildings where the current coping is worn or failing, and new-build housing where 2mm sloping coping is specified. For replacement work, check the external leg dimension of the existing coping before ordering: if the existing system uses a 125mm external leg, order the 125mm replacement to avoid a profile mismatch. For refurbishment on commercial buildings where 3mm coping is the original specification, use the 3mm sloping coping range throughout.

Part of a Complete 2mm Sloping Coping System | 100mm External Leg

This 3m section is the primary run length in the 2mm aluminium sloping coping system with a 100mm external leg. A complete parapet installation needs lengths in the correct mix, corner pieces at every change of direction, stopends at every run terminal, brackets at the right centres, sealant at every joint, and colour coded fasteners. Order everything from the same Chelmsford manufacturer to get matching profiles, consistent colour and a system that fits together without surprises on site. The full 2mm sloping coping system with 100mm external leg includes:

For the full sloping coping range including 125mm external leg and 3mm commercial versions, visit the Aluminium Sloping Coping collection page. For flat coping in the same concealed bracket system, the 2mm aluminium flat coping range covers lengths, corners and accessories in the same RAL colour options.

Standards and Compliance

Aluminium sloping coping on flat roof parapets in the UK is specified and installed under BS 6229:2018 - Flat Roofs with Continuously Supported Flexible Waterproof Coverings. This standard sets out parapet and edge detailing requirements for flat roofs, covering coping specification, joint treatment and fixing requirements. A correctly installed 2mm aluminium sloping coping system with sealant-bedded joints, brackets at the correct centres and properly fitted terminal components is consistent with the weathertight parapet detailing requirements of this standard.

The external grade polyester powder coat finish applied to all Online Metal Store Ltd sloping coping components meets the requirements of BS EN 12206-1 - Organic Coatings on Aluminium and Aluminium Alloys. The same coating specification applies to every component ordered from this range, ensuring consistent colour, gloss and durability from 3m sections through to corners and stopends.

For NHBC-registered new-build projects, Chapter 7.1 of the NHBC Standards covers parapet wall and flat roof construction requirements. A 2mm aluminium sloping coping system with properly sized, correctly installed sections and fully sealed joints is consistent with these requirements on new-build completions where sloping coping is the specified parapet cap.

 Download Our Colour Chart

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

Related System Products