Our 150mm cast iron guttering is the largest size in the Plain Half Round range and is designed for bigger roof areas where extra rainwater capacity is needed.
Also known as 6-inch cast iron guttering, it is particularly well suited to large period homes, country houses, barns, commercial buildings and restoration projects where a smaller profile may struggle with heavier rainfall.
The Alumasc Apex Heritage system uses 1.83m cast iron gutter lengths, with a full range of matching fittings available to complete the installation. These include unions, internal and external stop ends, 90° and 135° angles, fascia brackets, rafter brackets and compatible outlets for larger rainwater runs.
From the gutter outlet, you can continue the system with our matching cast iron downpipes, including bends, offsets, brackets and shoes. For valleys, parapets or areas where several roof sections feed into one point, our cast iron hoppers are also worth considering.
The range is available in factory-painted black, primed and selected custom RAL finishes, making it suitable for both heritage and modern specification work.
If you are unsure whether 150mm is necessary for your project, our Cast Iron Guttering Sizes Explained guide will help. You can also compare the full Plain Half Round Cast Iron Guttering range, including 100mm, 115mm and 125mm options.
Alumasc Apex 150mm (6") x 1.83m Half Round Cast Iron Gutter - Black
Alumasc Apex 150mm (6") Half Round Cast Iron Fascia Bracket - Black
Alumasc Apex 150mm (6") Half Round Rise & Fall Bracket for Cast Iron Gutter - Black
Alumasc Apex 150mm (6") Half Round Side Fix Rafter Bracket for Cast Iron Gutter -Black
Alumasc Apex 150mm (6") Half Round Top Fix Rafter Bracket for Cast Iron Gutter - Black
Alumasc Apex 150mm (6") Half Round Cast Iron External Stop End - Black
Alumasc Apex 150mm (6") Half Round Cast Iron Internal Stop End - Black
Alumasc Apex 150mm (6") Half Round Cast Iron Gutter Union - Black
Alumasc Apex 150mm (6") Half Round Cast Iron 90 degree Gutter Angle - Black
Alumasc Apex 150mm (6") Half Round Cast Iron 135 degree Gutter Angle - Black
Alumasc Apex 150mm (6") Half Round Cast Iron 75mm (3") Gutter Outlet - Black
Alumasc Apex 150mm (6") Half Round Cast Iron 100mm (4") Gutter Outlet - Black
Alumasc Apex 150mm (6") Half Round Cast Iron Gutter 1.83m Length - Primed
Alumasc Apex 150mm (6") Half Round Cast Iron Fascia Bracket - Primed
Alumasc Apex 150mm (6") Half Round Rise & Fall Bracket for Cast Iron Gutter - Zinc Plated
Alumasc Apex 150mm (6") Half Round Side Fix Rafter Bracket for Cast Iron Gutter - Zinc Plated
Alumasc Apex 150mm (6") Half Round Top Fix Rafter Bracket for Cast Iron Gutter - Zinc Plated
Alumasc Apex 150mm (6") Half Round Cast Iron External Stop End - Primed
Alumasc Apex 150mm (6") Half Round Cast Iron Internal Stop End - Primed
Alumasc Apex 150mm (6") Half Round Cast Iron Gutter Union - Primed
Alumasc Apex 150mm (6") Half Round Cast Iron 90 degree Gutter Angle - Primed
Alumasc Apex 150mm (6") Half Round Cast Iron 135 degree Gutter Angle - Primed
Alumasc Apex 150mm (6") Half Round Cast Iron 75mm (3") Gutter Outlet - Primed
Alumasc Apex 150mm (6") Half Round Cast Iron 100mm (4") Gutter Outlet - Primed
Alumasc Apex 150mm (6") x 1.83m Half Round Cast Iron Gutter - One of 6 CI Standard RAL Colours TBC
Alumasc Apex 150mm (6") Half Round Cast Iron Gutter Union - One of 6 CI Standard RAL Colours TBC
Popular black painted and primed cast iron products are usually available for next working day delivery when ordered before 11:30am, subject to stock. Custom RAL colours normally take around 7–10 working days.
For many UK homes, 115mm or 125mm guttering is a common choice. Smaller roof areas such as porches and outbuildings may use 100mm, while larger roofs or longer runs may need 150mm. Roof area, gutter profile and the number of outlets all matter, so it is worth checking before ordering.
Yes. We supply matching cast iron downpipes, hopper heads, brackets, outlets and fittings across the range, so you can put together a complete rainwater system rather than mixing different manufacturers or profiles.
Yes. Alongside painted black and primed finishes, many cast iron gutters, downpipes and hoppers can be supplied in custom RAL colours. Bespoke finishes are usually supplied within 7–10 working days.
Standard products can usually be returned within 30 days of delivery, although returns after the first 14 days may be subject to a restocking or handling charge. Made-to-order and custom-colour items are non-refundable, so it is worth checking sizes and finishes carefully before ordering.
Painted black products arrive with the finished colour already applied and are ready to install. Primed products are intended for projects where you want to apply the final decorative finish on site.
Normally, no. Plain Half Round, Beaded Half Round, Victorian Ogee, Moulded Ogee and Deepflow all use different shapes and fittings. It is best to keep the gutter lengths, unions, angles and outlets within the same profile and size.
Send us a photo and a few measurements. The overall width, depth, profile shape and downpipe diameter are usually enough to narrow it down and help identify the closest matching system.
You can buy individual components. We stock gutter lengths, unions, angles, stop ends, outlets, brackets, downpipes, bends, shoes, hopper heads and sundries separately, which is useful for repairs as well as complete installations.
Yes. If you have plans, elevations or even a marked-up sketch, send them over and we can help work through the likely gutter lengths, outlets, downpipes, angles and fittings required.
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