3mm Aluminium Flat Coping – 1m Length | 75mm External Leg

On most commercial parapet runs, the 3m section is the primary choice and the 2m section handles medium faces. The 1m section comes into its own in the situations where neither works cleanly: the final infill at the end of a longer run that falls short of 2m, a plant room enclosure with short return walls, a step parapet detail where a 3m or 2m section would either overshoot or waste significant material, and tight-access positions at height on a commercial building where manoeuvring a full 2m or 3m aluminium section is genuinely difficult. On a 22m commercial parapet that divides into seven 3m sections with 1m remaining, the 1m section is the correct final piece. Ordering an eighth 3m section and cutting 2m of waste on a non-returnable made-to-order product is not the right approach.

This is the 3mm aluminium flat coping in a 1m length with a 75mm external leg. It is the short infill section in the commercial 3mm flat coping system from Online Metal Store Ltd, manufactured at the Chelmsford facility in Essex. Available powder coated in any RAL colour, in 23 commercial width sizes from 510mm to 1060mm, made to order and non-returnable unless faulty.

When the 1m Section Is the Right Choice

Final Infill on Long Commercial Runs

The most common application for a 1m flat coping section is as the final piece at the end of a longer commercial parapet run. On a 19m run, six 3m sections give 18m with 1m remaining. A 1m section closes out the run with one additional joint and no waste from a larger section. This is the correct planning approach on a made-to-order product at this price point: match the sections to the run length rather than ordering a larger section and cutting.

Short Commercial Parapet Details

Commercial buildings produce short parapet sections in places that domestic projects rarely do: plant room enclosures, lift shaft cap parapets, service duct covers, step parapet transitions, and return walls on complex plan forms. These sections are often between 600mm and 1500mm long. A 1m section serves all of them, either as a cut section for shorter positions or as a full-length piece for positions near 1m. On a building where these short details appear at multiple points, keeping 1m sections on the order simplifies the cut schedule on site.

Tight-Access Positions at Height

On commercial parapets at first-floor level or above, installing a 3m or 2m aluminium section in a tight access position can be difficult without assistance. A 1m section is lighter and more manageable in situations where the working platform is restricted, an adjacent structure limits the length that can be presented to the wall, or where an overhead obstruction prevents a longer section being lowered into position. Using 1m sections only in these positions, rather than across the whole installation, keeps joint count as low as possible while addressing the practical constraint.

Complex Parapet Plans with Multiple Short Sections

Commercial buildings with irregular plan forms, projecting elements and multiple re-entrant corners often produce parapet runs that include several short sections alongside the main straight runs. A mixed order of 3m primary lengths, 2m infill sections and 1m pieces covers the full range of face lengths on these buildings efficiently. Planning the section mix before ordering, rather than defaulting to one length for everything, minimises both waste and joint count.

Product Overview

This 1m section is part of the Online Metal Store Ltd 3mm aluminium flat coping system with a 75mm external leg, fabricated at the Chelmsford facility. The flat top surface gives a clean, horizontal profile at parapet level: the standard choice for commercial buildings, contemporary office and retail architecture, and modern residential projects where a minimalist parapet line is specified. At 3mm gauge, the section has greater cross-sectional rigidity than the 2mm domestic equivalent, providing better resistance to wind uplift forces and longer fatigue life on commercial and exposed-site parapets. The 75mm external leg and 75mm internal leg give equal overhang on both faces of the wall, which is the standard profile for flat coping on straightforward commercial parapets. The 5mm aluminium coping bracket is the correct concealed fixing bracket for this 3mm system.

The 1m section is compatible with all accessories in the 3mm 75mm flat coping system: the 2m section and 3m section in the same profile, all corner types, closed stopends, stopend upstands, the T-junction and the 5mm bracket. No component from the 2mm system can be substituted here. The profiles look similar but the wall thickness differs, and the dimensional interface between a 2mm accessory and a 3mm section will not be flush.

Key Benefits

Minimises Waste on Non-Returnable Made-to-Order Coping

On a commercial project where 3mm flat coping sections are ordered at this price, waste from oversized sections cut down on site adds up quickly across a full perimeter order. Ordering a 1m section for a 1m infill position rather than cutting from a 2m or 3m section is straightforward cost management. It also means any offcuts from longer sections are not created unnecessarily, which is particularly relevant on a made-to-order non-returnable product.

3mm Gauge for Commercial Specification Throughout

The 1m section is fabricated at the same 3mm gauge as the 2m and 3m sections in the same system. On a commercial parapet where 3mm has been specified for the primary lengths, every component including the infill sections must maintain that specification. A 2mm infill section in a 3mm commercial installation is under-specified for the site conditions that prompted the 3mm specification in the first place, and creates a profile mismatch at both junctions with the 3mm sections either side. For the full explanation of when 3mm is the right gauge, see the 3mm flat coping 2m length page.

Flat Profile for Consistent Horizontal Line

The flat top surface of this 1m section matches the flat profile of the 2m and 3m sections running either side of it. On a commercial building where the parapet line is visible at street level or from adjacent buildings, maintaining a consistent flat profile across every section including short infill pieces is part of the specification. A sloped infill section in a flat coping run would be immediately visible and unacceptable on any commercial project.

Any RAL Colour, Matched in the Same Batch

Ordering the 1m infill sections in the same RAL as the 2m and 3m primary sections, corners, stopends and brackets means all components go through the same coating batch at Chelmsford. The colour match across the full system is consistent because everything is coated together, regardless of section length.

Made to Order in Chelmsford

Fabricated at the Online Metal Store Ltd facility in Chelmsford to the width and colour specified at order. Made to order means non-returnable unless faulty. The sizing formula, wall width + 170mm, is explained in the size calculation section below. Apply it correctly before ordering, and check the result against the available 23 sizes before placing the order.

Technical Specifications

Material: 3mm grade aluminium

Profile: Flat coping length

Length: 1m (1000mm)

External Leg: 75mm

Internal Leg: 75mm (equal both sides)

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 340mm to 890mm (wall width + 170mm = 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 1m long.

Sizing Formula: Wall width + 170mm = size to order (75mm external leg + 75mm internal leg + 10mm + 10mm returns = 170mm)

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 flat coping only

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

Country of Manufacture: United Kingdom (Chelmsford, Essex)

Calculating the Width Size

The 23 sizes from 510mm to 1060mm refer to the WIDTH of the coping profile, not the run length. Every section on this page is 1m long. The formula for the 3mm flat coping 75mm equal-leg system is: wall width + 170mm = the size to order. This formula is the same for 1m, 2m and 3m sections in this system. A full worked guide is on the 3mm flat coping 2m length page, but here are the key steps:

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

• Add 75mm (external leg) + 75mm (internal leg) + 10mm + 10mm (returns) = 170mm.

• Total: wall width + 170mm = size to order. A 340mm wide commercial wall gives 510mm. A 440mm wall gives 610mm. A 565mm wall gives 735mm.

• Note: this formula is specific to the 3mm flat coping 75mm equal-leg system. Sloping coping uses different formulas (100mm leg: wall width + 195mm; 125mm leg: wall width + 220mm). Apply the correct formula for the system you are ordering.

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

Bracket Specification for 3mm Flat Coping

Every 3mm flat coping installation, including 1m sections, requires the 5mm aluminium coping bracket. The 4mm bracket is for 2mm flat coping only. For a 1m section, a minimum of two brackets are needed: one within 150-200mm of each end. On exposed sites or elevated commercial buildings where wind loading calculations have been carried out, follow the engineered bracket centres. The 5mm bracket is fixed to the wall top before the coping is installed; the flat coping section then presses down onto the bracket from above, giving a clean concealed fixing with no fastener penetrating the coping face or top surface.

How to Install a 1m 3mm Flat Coping Section

Fix the 5mm brackets in position before pressing the coping. For a 1m section, two brackets at approximately 700-800mm apart cover the section correctly within the 1000mm maximum centre requirement. On a complex parapet layout where 1m sections sit adjacent to 2m or 3m sections, confirm the bracket positions for the entire run before fixing any of them, so the spacing is consistent across the full installation.

Apply a continuous bead of colour coded sealant in the matching RAL to the internal face of the joint before butting the 1m section up to the adjacent section. The sealant bead is the primary weathertight seal at the joint. Press the section home and lock to the brackets using colour coded metal fasteners in the matching RAL. Apply a neat finishing bead of sealant on the external joint faces.

Where the 3mm 1m Flat Coping Section Is Used

Infill at the End of Long Commercial Parapet Runs

On a commercial parapet run of 22m, seven 3m sections give 21m with 1m remaining. A 1m section closes the run with one additional joint. On a run of 19m, six 3m sections plus a 1m section covers 19m with six joints total. This is the correct and most economical approach on a non-returnable made-to-order commercial product. Ordering a full additional 3m section and cutting 2m of waste adds cost without any installation benefit.

Plant Room Enclosures and Service Infrastructure

Plant rooms, lift shaft enclosures, stair overruns and similar service elements on commercial flat roofs produce short parapet cap requirements. The parapets around these elements are often under 2m per face, sometimes significantly less. A 1m section handles these details efficiently, either as a full-length piece or as a section cut to the exact face length on site. On a commercial building with multiple plant elements, a small stock of 1m sections covers the infill requirements without the waste of cutting multiple 2m or 3m sections.

Step Parapet Transitions

Commercial buildings with stepped rooflines have parapet copings that change level at the transition points. The horizontal section of coping that bridges the step is typically short, often 500mm to 1000mm. A 1m section handles this detail cleanly in the 3mm gauge, maintaining the correct specification at every point in the perimeter including the step transitions that longer sections cannot serve without waste or awkward cutting.

Replacement Sections on Existing 3mm Flat Coping

When isolated sections of existing 3mm flat coping are damaged or have failed on a commercial building, the replacement must be 3mm gauge in the matching profile and size. A 1m replacement section is often the most practical choice for spot repairs: it covers the damaged section with a single piece and minimal disturbance to the surrounding installation. Order the 1m section in the correct size using the wall width + 170mm formula and in the RAL colour to match the existing coping. Source the 3mm 90 degree corners and 5mm brackets from the same Chelmsford manufacturer to ensure profile and colour consistency.

Frequently Asked Questions

When should I order 1m sections rather than 2m or 3m?

Order 1m sections for three situations: as the final infill piece at the end of a longer run where the remaining length is under 2m; for genuinely short parapet sections (plant rooms, step details, tight returns) where a longer section would either overshoot or create significant waste; and for tight-access positions at height where a 2m or 3m section is difficult to handle. For all other commercial parapet positions, plan with 3m sections first and use 2m sections for medium faces and infill. The 1m section is not the right primary length for long commercial runs, where its additional joints have no offsetting advantage.

What size do I need for my commercial parapet?

Wall width + 170mm = the size to order for the 3mm flat coping 75mm equal-leg system. A 340mm wide commercial parapet gives 510mm. A 440mm wall gives 610mm. A 565mm wall gives 735mm. The 23 sizes refer to coping widths, not run lengths. Every section on this page is 1m long regardless of the size selected.

What bracket do I need for 3mm flat coping 1m sections?

The 5mm aluminium coping bracket is the correct bracket for all 3mm flat coping. The 4mm bracket is for 2mm flat coping only. For a 1m section, you need a minimum of two brackets at approximately 700-800mm apart. This keeps both bracket spacings within the 1000mm maximum centre requirement.

Can I cut 3mm aluminium flat coping to 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 cutting disc. Cut square to the profile, deburr the cut edge with a file, and fit a closed stopend or a sealant bead at the cut end where it forms a run terminal. On a commercial project with a quantity of cut sections required, marking out and cutting all sections before starting installation is more efficient than cutting each one as you go.

Is this product anodised or powder coated?

Powder coated only. The finish is an external grade polyester powder coat available in any RAL colour. These products are not anodised. If the current product page contains any reference to anodising or anodized finishes, these statements are incorrect and must be removed before publication. Powder coating is the only available finish across the entire Online Metal Store Ltd 3mm flat coping range.

Part of a Complete 3mm Flat Coping System | 75mm External Leg

This 1m section is the short infill length in the 3mm aluminium flat coping system with a 75mm external leg. Order all components from the same Chelmsford manufacturer to get matching profiles, consistent colour, and a system that fits together correctly on site. The full 3mm flat coping system with 75mm external leg includes:

• 3mm Aluminium Flat Coping - 1m Length | 75mm External Leg (this product)

• 3mm Aluminium Flat Coping - 2m Length | 75mm External Leg

• 3mm Aluminium Flat Coping - 3m Length | 75mm External Leg

• 3mm Aluminium Flat Coping - 90 Degree Corner | 75mm External Leg

• 3mm Aluminium Flat Coping - 135 Degree Corner | 75mm External Leg

• 3mm Aluminium Flat Coping - Closed Stopend | 75mm External Leg

• 3mm Aluminium Flat Coping - Stopend Upstand | 75mm External Leg

• 3mm Aluminium Flat Coping - 90 Degree T-Junction | 75mm External Leg

• 5mm Aluminium Coping Bracket

• Colour Coded Sealant 300ml

• Colour Coded Fasteners (Metal)

For the full 3mm and 2mm flat coping ranges, visit the Aluminium Flat Copings collection page and the 3mm Aluminium Flat Coping collection page. For guidance on when 3mm is the correct specification over 2mm, and for the full 1m vs 2m vs 3m length selection guide, see the 3mm flat coping 2m length page.

Standards and Compliance

Aluminium flat coping on commercial flat roof parapets in the UK is specified and installed 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, joint treatment and fixing requirements. A 3mm aluminium flat coping installation with correctly spaced 5mm brackets and sealant-bedded joints throughout is consistent with the weathertight parapet requirements of this standard, whether the installation uses 3m primary sections or 1m infill pieces or a combination of both.

The external grade polyester powder coat applied to all 3mm flat coping components meets the requirements of BS EN 12206-1 - Organic Coatings on Aluminium and Aluminium Alloys. The same coating standard applies to 1m infill sections as to primary lengths, ensuring that the full installed system, including every short piece, maintains consistent colour and durability.