If you’re fitting cast iron guttering, around 900mm between brackets is the normal starting point. But that isn’t the whole story.
Cast iron is heavy, especially once the gutter is full of water, so the brackets need to support the run properly.
You’ll also normally need extra support around joints, outlets and angles rather than simply measuring 900mm all the way along and calling it done.
And importantly, check which system you’re installing. Manufacturer guidance does vary slightly.
How Far Apart Should Alumasc Cast Iron Gutter Brackets Be?
For Alumasc Apex Heritage cast iron guttering, the installation guidance says brackets should generally be positioned at 915mm centres.
You then need additional brackets around gutter joints, as well as support around outlets and angles.
So on a standard 1.83m gutter length, you’re normally looking at roughly three support positions across the run once everything is laid out properly.
That applies across the Apex Heritage system, although the exact bracket itself will depend on how the gutter is being fixed.
If you’re buying a new system, you can see the different profiles in our main cast iron guttering range.
What About Hargreaves Cast Iron Guttering?
Hargreaves Foundry gives very similar guidance, but not exactly the same.
For Hargreaves Premier guttering, the first bracket should be positioned around 150mm from the end of the run, with the remaining brackets fitted at a maximum of 900mm centres.
That’s worth knowing if you’re fitting our Hargreaves Cast Iron Deepflow guttering.
In other words, don’t mix the instructions from one manufacturer with another system just because both are cast iron.
You Need Extra Brackets Around Joints
This is the bit that often gets missed.
Imagine a 6-metre gutter run. You wouldn’t simply put a bracket every 900mm without thinking about where the gutter lengths actually join.
The joints are important because that’s where two heavy cast sections meet.
With the Alumasc system, additional brackets should be positioned on either side of the gutter joint. You also want proper support around outlets and corners, rather than leaving those fittings hanging between two distant brackets.
So when working out how many brackets to buy, don’t just divide the total length by 900mm.
Lay the system out first.
Work out where you have:
- Gutter joints
- Running outlets
- Stop-end outlets
- Internal angles
- External angles
- The beginning and end of the run
Then position the normal intermediate brackets between those points.
Do Cast Iron Gutters Need a Fall?
Yes, ideally.
The gutter needs to move rainwater towards the outlet rather than allowing it to sit along the run.
For Alumasc cast iron guttering, the recommended fall is generally between 1:600 and 1:350. Hargreaves gives similar guidance.
That’s not an enormous visible slope. Done properly, you probably won’t notice it when looking at the roofline.
A string line makes setting the brackets much easier. Position the first and last brackets, establish the required fall, then use the line to position everything in between.
If the roof arrangement makes a fall impractical, some systems can be installed level, but you should follow the guidance for the gutter you’re actually using.
Which Type of Cast Iron Gutter Bracket Do I Need?
Spacing is only half the job. The bracket itself needs to suit the building.
If you have a sound timber fascia, fascia brackets are usually the straightforward option.
Older buildings don’t always have a fascia board though. In that case you may need top-fix rafter brackets, side-fix rafter brackets or rise-and-fall brackets.
That’s fairly common on period properties.
Our Plain Half Round Cast Iron Guttering range includes several bracket styles for exactly this reason.
Don’t automatically copy the bracket type that happens to be on the building now either. If the roof or fascia has been altered over the years, there may be a better fixing arrangement available. Feel free to email us if you need help: info@castironguttering.co.uk.
What Happens If Cast Iron Brackets Are Too Far Apart?
You’re asking the gutter to span too much distance between supports.
Over time that can put unnecessary strain on the gutter, the joints and the fixing points. A poorly supported section may also sit out of alignment, which doesn’t help water flow.
Cast iron guttering is extremely strong, but it’s also heavy. Proper bracket positioning is part of the system, not an optional extra.
And putting one extra bracket in while everything is accessible is considerably easier than trying to correct a poorly supported run later.
A Simple Rule to Remember
If you just need a quick reference:
Alumasc Apex Heritage: roughly 915mm centres, with additional support around joints, outlets and angles.
Hargreaves Premier / Deepflow: 900mm maximum centres, starting approximately 150mm from the end of the run.
Then always check the installation instructions for the actual profile you’ve bought.
If you’re not sure which cast iron system you have in the first place, our guide on How to Identify Your Existing Cast Iron Gutter Profile is worth reading before ordering brackets or replacement fittings.