Our 100mm cast iron guttering is the smallest size in the Plain Half Round range and is a great choice for much smaller roof areas, porches, extensions, outbuildings and shorter gutter runs where a larger profile may look oversized.
Also commonly referred to as 4-inch cast iron guttering, this system is made up of 1.83m gutter lengths with all the matching fittings needed to build a complete run. That includes unions, stop ends, 90° and 135° angles, fascia brackets, rafter brackets and outlets for 65mm or 75mm round downpipes.
At Cast Iron Warehouse, we supply the complete Apex Heritage system in black, primed and selected custom colour finishes, making it easy to match new rainwater goods to both traditional and modern properties.
Not sure whether 100mm is large enough for your roof? Have a look at our Cast Iron Guttering Sizes Explained guide before ordering.
For the vertical run, pair the system with our cast iron downpipes, where you’ll find matching round pipes, offsets, bends, shoes and brackets. If your roof layout discharges from a valley, parapet or other concentrated outlet, our cast iron hoppers can also be incorporated into the rainwater system.
Alumasc Apex 100mm (4") Half Round Cast Iron Gutter 1.83m Length - Black
Alumasc Apex 100mm (4") Half Round Cast Iron Fascia Bracket - Black
Alumasc Apex 100mm (4") Half Round Rise & Fall Bracket for Cast Iron Gutter - Black
Alumasc Apex 100mm (4") Half Round Side Fix Rafter Bracket for Cast Iron Gutter -Black
Alumasc Apex 100mm (4") Half Round Top Fix Rafter Bracket for Cast Iron Gutter - Black
Alumasc Apex 100mm (4") Half Round Cast Iron External Stop End - Black
Alumasc Apex 100mm (4") Half Round Cast Iron Internal Stop End - Black
Alumasc Apex 100mm (4") Half Round Cast Iron Gutter Union - Black
Alumasc Apex 100mm (4") Half Round Cast Iron 90 degree Gutter Angle - Black
Alumasc Apex 100mm (4") Half Round Cast Iron 135 degree Gutter Angle - Black
Alumasc Apex 100mm (4") Half Round Cast Iron 65mm (2.5") Gutter Outlet - Black
Alumasc Apex 100mm (4") Half Round Cast Iron 75mm (3") Gutter Outlet - Black
Alumasc Apex 100mm (4") Half Round Cast Iron 65mm (2.5") Drop End Gutter Outlet - External - Black
Alumasc Apex 100mm (4") Half Round Cast Iron 65mm (2.5") Drop End Gutter Outlet - Internal - Black
Alumasc Apex 100mm (4") Half Round Cast Iron Gutter 1.83m Length - Primed
Alumasc Apex 100mm (4") Half Round Cast Iron Fascia Bracket - Primed
Alumasc Apex 100mm (4") Half Round Rise & Fall Bracket for Cast Iron Gutter - Zinc Plated
Alumasc Apex 100mm (4") Half Round Side Fix Rafter Bracket for Cast Iron Gutter - Zinc Plated
Alumasc Apex 100mm (4") Half Round Top Fix Rafter Bracket for Cast Iron Gutter - Zinc Plated
Alumasc Apex 100mm (4") Half Round Cast Iron External Stop End - Primed
Alumasc Apex 100mm (4") Half Round Cast Iron Internal Stop End - Primed
Alumasc Apex 100mm (4") Half Round Cast Iron Gutter Union - Primed
Alumasc Apex 100mm (4") Half Round Cast Iron 90 degree Gutter Angle - Primed
Alumasc Apex 100mm (4") Half Round Cast Iron 135 degree Gutter Angle - Primed
Alumasc Apex 100mm (4") Half Round Cast Iron 65mm (2.5") Gutter Outlet - Primed
Alumasc Apex 100mm (4") Half Round Cast Iron 75mm (3") Gutter Outlet - Primed
Alumasc Apex 100mm (4") Half Round Cast Iron 65mm (2.5") Drop End Gutter Outlet - External - Primed
Alumasc Apex 100mm (4") Half Round Cast Iron 65mm (2.5") Drop End Gutter Outlet - External - Primed
Alumasc Apex 100mm (4") Half Round Cast Iron Fascia Bracket - One of 6 CI Standard RAL Colours TBC
Alumasc Apex 100mm (4") 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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