The best guttering material depends on the house it is going on. A plastic run is light, quick to fit and low in price. Cast iron is heavy, slow to fit and can outlast the person who paid for it. Aluminium sits between them in weight and in cost, and comes in colours that plastic does not hold as well.
This guide sets the three against each other. The life figures are the weakest part of the picture, because the only published comparison we found comes from a single gutter-cleaning firm, so we give them with that warning. For the board the gutter hangs from, see uPVC, timber or aluminium fascias. The hub page on guttering, soffits and fascias covers the job as a whole.
The three materials in plain terms
uPVC gutter is an extruded plastic channel, supplied in lengths that clip together with rubber seals at the joints. It is the commonest gutter on houses built or refitted in the last few decades. Cast iron is poured into moulds and is made in sections, with bolted joints sealed with putty or sealant and often with fine decorative detail on the front. Aluminium is formed from sheet or extruded, and is coated in a factory colour.
All three do the same task: catch the water that runs off the roof and carry it to a downpipe. The differences lie in weight, joints, durability and look. Weight affects what the fascia and brackets must bear. Joints are where gutters leak, and the more joints a run has, the more places a seal can fail. Our guide to the gutter profiles deals with the shape of the channel; here we are only dealing with what it is made of.
How long each one lasts
A cleaning firm called Pureseal Services published a comparison in December 2025 that gives uPVC gutters 10 to 20 years, aluminium 20 to 30 years, and cast iron 40 to 70 years, sometimes more than 100. Those figures come from one source with an interest in gutter maintenance, so treat them as indicative, not as a rule. We have not found a second published comparison to set beside them.
| Material | Typical life |
|---|---|
| uPVC | 10 to 20 years |
| Aluminium | 20 to 30 years |
| Cast iron | 40 to 70 years, sometimes 100 or more |
Lifespan also depends on things the material cannot control: whether the fascia stays sound, whether leaves are cleared, and whether the brackets are spaced for the load. A cast iron gutter on rotten brackets and a failing board will not reach its potential. A plastic gutter that is cleaned and well supported will go beyond the low end. Our gutter lifespan guide covers what shortens each.
What each costs, and what the figures cannot tell you
MyBuilder's 2026 price guide for roofline replacement gives £30 to £70 per metre for guttering in the UK. That is one range for all materials, not a price per material, so it should not be read as a statement that cast iron costs the same as plastic. In practice plastic sits at the lower end, aluminium above it, and cast iron higher still, but a price for cast iron is set by survey rather than a published per-metre rate.
Why iron costs more to fit
Cast iron is heavy, so brackets and the fascia or rafter ends behind them must be stronger. Lengths are bolted together and the joints are sealed by hand. A run that is mostly sound but cracked in one place is often repaired rather than replaced, which is cheaper than a new run but needs somebody who knows how to do it. Scaffold is another cost on any gutter above a ladder's reach; the range is £20 to £40 per m² in the same MyBuilder guide.
Total cost over time
A cheaper gutter that is replaced twice may cost more across the life of a house than one iron run that is looked after. That sum depends on the figures above, which are wide, so work it out on your own quote rather than on a rule of thumb. Our fascia, soffit and gutter replacement costs guide shows the per-metre working.
Plastic gutters: where they suit and where they don't
uPVC is light and simple to fit, which keeps both the supply and the labour costs down. It does not rust and it is not heavy on the fascia. It is a sensible choice on modern houses, extensions, outbuildings and the back of a house where appearance counts for less.
Its weak points
The joints are rubber seals, and the seals age. A plastic gutter that drips at a joint is often asking for the seal to be replaced, not the run. Long runs expand and contract, and a run that is clipped too tight can bow or pull a joint open. In bright sun the plastic can lose its colour and become brittle.
On older houses
A bright white or black plastic gutter on a stone house with deep eaves can look out of place, and a protected house (listed, or inside a conservation area) may be expected to keep a traditional material. Stroud District has 41 conservation areas, with Article 4 Directions in five. The council's page on those directions does not say whether they cover roof edges, so protected houses should raise it with the council before work; see roofline work in conservation areas.
Cast iron gutters on period homes
Cast iron is the traditional gutter on Georgian, Victorian and earlier houses, and many of the stone-built mills and cottages around the Stroud valleys still carry it. It is heavy, durable and detailed, and it can be repaired: cracked sections can be replaced one at a time and the rest left in place.
What it asks of you
Iron rusts if the paint fails, and it needs repainting inside and out on a cycle. Joints leak when the sealant dries out. Brackets must be strong and well fixed into sound timber or masonry. Left alone, a blocked cast iron gutter holds water and rusts from the inside. The upkeep is real, which is why the right question is whether you will do it. Our cast iron gutters page goes into the repair and replacement options.
If a cast iron run is mostly sound, repair is nearly always worth pricing before replacement; the quote can show both.
Where cast iron has gone beyond repair, a new cast iron run, or a cast aluminium one made to the same profile, can be fitted. Like-for-like is our approach on older roofs, so iron stays iron unless the council or the condition of the building says otherwise.
Aluminium gutters: a middle path
Aluminium is lighter than iron, does not rust, and comes in factory colours and in long lengths. It is often chosen for newer builds, extensions and for houses where a plastic gutter looks cheap but iron would be too heavy or expensive. It can also be formed on site in one length, which removes most of the joints. We deal with that separately in continuous-run aluminium gutters.
Cautions
Aluminium dents more easily than iron, and a ladder left against it will show. Where it meets other metals, such as lead or copper on a roof or porch, it can corrode at the contact. A good installer separates them. Colour fade is slower than on plastic but not absent.
Fit on a stone house
A dark, slim aluminium section can sit well on a stone house where iron is no longer available or a protected-building officer accepts it. Ask first. On a listed house the effect on character is for the council to judge, and it describes the protection as covering the whole building.
Brackets, falls and what the material does to them
Material and fixing go together. A plastic run is light and, as a manufacturer's data shows, wants closely spaced brackets: FloPlast's MiniFlo guide caps fascia bracket spacing at 500 mm on straight runs, while Brett Martin puts the limit at 900 mm and goes closer than 600 mm in areas of heavy snow. The two products differ, so the spacing printed in the data for the system being fitted is the one to follow.
The fall
All three materials need a gentle slope towards the outlet. The published manufacturer advice runs from about 1:600 to 1:350, depending on the system. Iron is stiff and holds its line, so the fall is set once and stays. Plastic and thin aluminium can sag between brackets if they are too far apart, which flattens the fall and leaves a puddle that never drains. Gutter fall shows how it is set and checked.
Older goods and asbestos cement
Some rainwater goods on mid-century outbuildings and garages are asbestos cement. HSE guidance covers careful removal of whole pieces as non-licensed work, and that is a reason to have the material identified before anything is cut, drilled or cleaned with a pressure washer.
Fitting the gutter to the house you have
Whichever material wins, a few site facts decide how the job goes. A steep lane or a terrace that drops away behind the house changes how a scaffold or tower can be stood, and so the cost of reaching the eaves. Long stone-built elevations, such as those on mill buildings, call for more brackets and more outlets than a short suburban wall. Old stone walls rarely give a clean line, so gutter lengths are cut and set to suit the wall, not a standard module.
At the survey we record the length of every run, the number of corners and stop ends, the position of each outlet and the condition of the fascia timber. From those counts the written quote covers the gutter, the downpipes and the fixings.
Choosing, and keeping the gutters clear
A short way to choose: plastic where cost and ease matter and the building is not protected; aluminium where you want a lighter, cleaner line and a longer life than plastic; cast iron where the house is old, the gutter is part of its character, and you accept the upkeep.
Whatever you choose, the gutter only works if the water gets to the outlet. Leaves, moss and roof grit build up behind the fall, and a full gutter overflows, soaks the fascia and stains the wall. Our gutter cleaning guide explains a sensible routine, and our written quote covers the gutter run, brackets, outlets and downpipes. The fitting is covered by our written 10-year workmanship guarantee.