A gutter looks simple: a channel on the edge of the roof that carries rain to a downpipe. In practice it is one of the hardest-working parts of a house. It holds a full load of water in a storm, sits in direct sun for years, gets leaned on by ladders and has to keep a steady slope along its whole length so the water actually runs.
The material you choose decides how much it weighs, how it joins, how it fails and what it asks of you afterwards. A plastic run hung on a 1960s bungalow, a painted metal run on a new extension and a heavy iron run on a Victorian villa are three sensible answers to three different houses, not three versions of one answer.
This guide weighs the three materials against each other. It covers where each earns its place, what goes wrong, how the sea air affects maintenance, and what a typical price looks like, so you can judge a quote against something. It forms part of our wider guide to gutters, soffits and fascias.
What every gutter has to put up with
Before comparing materials, it helps to be clear about the work. A gutter carries water from the roof edge to a downpipe, and the water arrives faster than many people expect. A single gutter run on a pitched roof collects the rain from the whole slope above it, then funnels it towards one outlet. In a downpour it can fill in moments.
The channel therefore needs three things from its material: strength to carry the water without sagging, joints that stay sealed as the metal or plastic moves, and a surface that survives sun, frost and wet without breaking down.
Fall and support
Every system, whatever it is made of, relies on a gentle slope towards the outlet. Makers' installation guides call for a slight slope, in the region of 1:600 to 1:350 depending on the system, so you will not see the slope by eye, but without it water stands in the channel and drags the run down. Brett Martin advises supports spaced no more than 900mm apart, and heavier materials need them closer still.
Fixings come first
A well-made gutter on a poor fascia will fail, and so will a good fascia carrying a flimsy gutter. A heavy cast iron run asks for sound timber and strong brackets. A light plastic run asks for correct support spacing so it does not belly between brackets. Our survey begins with the board and the rafter feet, which we photograph for you, and the talk about material comes afterwards. If the fascia needs attention too, our comparison of uPVC and timber fascias covers that choice.
uPVC: the everyday choice
Plastic guttering is what most houses built or re-guttered in the last few decades carry. It is light enough for one person to handle, it does not rust and it is sold in several profiles, each with matching fittings. It is also the lowest-cost of the three to supply and fit, which is why it dominates.
The joints are where it can go wrong. Lengths slot into joint pieces with a rubber seal, and the seal can dry out, shift or collect grit, which lets a slow drip start at the join. Plastic also moves with temperature, so a run fitted tight can pull out of its brackets on a hot day. A good fitter leaves room in each joint for that movement.
Age and appearance
Sun is the main enemy. Over time ultraviolet light can chalk the surface, fade the colour and make the plastic more brittle, and a brittle gutter is the one that cracks when a ladder touches it. White and black age differently, and a mixture of old and new lengths shows. If one corner has failed and the rest is sound, replacing a section is possible, but the new part rarely matches the weathered run beside it.
Plastic cannot be repaired in the way metal can. A cracked length is swapped out, and a sagging run is rehung, which often means new brackets. For lifespan, published figures disagree and depend heavily on exposure and fitting, so treat any number as a range. The boards behind the gutter have their own lifespan page, how long uPVC fascias last, and the same sun and fitting questions apply.
Where uPVC suits best is a modern or mid-century house, a bungalow with long straight runs, or any property where cost and simplicity matter more than character.
Aluminium: light, stiff and made to measure
Aluminium sits in the middle on price and weight. It is far lighter than iron but stiffer than plastic, it does not rust in the way iron does, and it holds a factory-applied paint finish in a wide range of colours. Dark greys and blacks are popular, and a metal gutter against a dark fascia gives a crisp, modern edge.
There are two main ways of getting it. Sectional aluminium comes in lengths, joined like plastic. Continuous aluminium is formed on site from a coil of metal by a machine, so a long run is a single piece with no joints along it, only at the corners and outlets. Fewer joints mean fewer places to drip, which is the main argument for it. The joint-free route needs a coil of metal and a forming machine brought to the house, which is why it is a specialist job.
Where aluminium falls short
It dents. A ladder leaned against the front of a thin aluminium gutter can leave a mark that stays, and hail or a heavy blow does the same. Colour coatings can scratch, and cut edges need to be sealed so the finish does not lift. Fittings must also be matched to the system, because mixing makers' parts often leaves leaks.
It costs more than plastic, and a continuous run needs a fitter with the machine, which narrows the field. For that price you get a clean line, a long life if the finish is looked after and a gutter that looks the part on a modern extension, a flat-fronted terrace or any building where a plastic profile would seem cheap.
Aluminium is also the usual answer when a householder wants a metal gutter without the weight or the upkeep of iron.
Cast iron: weight, character and upkeep
Cast iron was the standard gutter material until plastic arrived, and it remains the right answer on many Victorian, Edwardian and Georgian buildings. The reasons are visual and practical. The profiles, such as ogee and half-round with decorative brackets, match the age of the house, and the metal is heavy enough to hold its line for decades.
The weight is the catch. A cast iron run needs strong brackets screwed into sound timber or masonry, and it takes two people to hang. It also costs most to buy and fit, and it is the one material where original lengths are worth saving where they can be.
Rust, joints and repair
Iron rusts when its paint film fails. A well-coated run can last a very long time, but a patch where the paint has gone starts to scale, and the scale spreads under the paint around it. The usual job is to clean back to bare metal, prime and repaint, with particular attention to the inside of the channel, which collects wet leaves and silt.
Joints are bolted and sealed. Over the years the sealant fails and a drip appears at the joint. Often it can be taken apart, cleaned and resealed. Cracked lengths can be replaced with new castings or lookalikes, and in some cases a fitter can repair a break.
On a listed or period building, replacing like with like is normally the easy route, and swapping to plastic can need consent. Our dedicated page on cast iron guttering sets out repair, replacement and the consent questions in more detail.
For a house built in the last half century, cast iron is rarely worth the extra, unless the owner wants the look.
Sea air, salt and what to do about it
Near the Channel, every material is exposed to salt in the air, to driving rain off the sea and to long spells of damp. The effect on a gutter is different from the effect on a roof tile, because a gutter has surfaces that rain washes and surfaces it does not.
HomeBuilding points out that on a seaside house the soffits and fascias collect a salty film out of the air, and rain never reaches them to rinse it off. The back of a gutter, its brackets and the underside of the run sit in the same shelter, so the same thinking applies. Regular rinsing with clean water removes the film before it can sit and hold moisture. Our page on salt deposits on fascias and soffits explains the routine.
What this means for the choice
A plastic gutter does not corrode, so the job is rinsing it and keeping it clear. A painted metal gutter relies on its coating, so the thing to watch is chips and scratches, which should be touched in before moisture gets under them. A cast iron gutter relies on paint entirely, and the repaint cycle is the price of owning it.
No single material wins by the sea. The outcome depends on the finish, the fitting and how closely the house is looked after, so we judge each run on its own condition. A gutter you can reach and rinse at ground-floor or first-floor level will stay in better order than one nobody ever checks.
Any run on a seafront or an exposed elevation is worth a look from a ladder once the stormy months have passed.
Cost, comparison and choosing for your house
On price, MyBuilder (updated 21/08/2026) gives a typical UK range of £30 to £70 per metre for guttering replacement. That figure is a spread across materials, not a price for one, and it does not include a scaffold if the work needs one. Weight, finish and fitting time all push the price up, so a heavy or joint-free run costs more to hang than a light plastic one. What you pay turns on how long the run is, how many corners and outlets it has, how high the eaves sit, how we reach them and what condition the fascia behind is in.
| Material | Weight | Main upkeep | Best suited to |
|---|---|---|---|
| uPVC | Light | Rinse, clear, check joint seals | Modern houses, bungalows |
| Aluminium | Light to medium | Touch in the finish | Extensions, flat-fronted terraces |
| Cast iron | Heavy | Repaint, reseal joints | Period and listed buildings |
How we choose
We inspect the house, the fascia and the run already there, show you photographs, and say which material fits. Sometimes that means keeping iron and repairing it. Sometimes it means plastic, because the house is modern and the budget matters more than the finish. The advice is always the least work that properly deals with the fault, and the written quote with one total follows once we have surveyed.
Ask any contractor to confirm in writing whether the quote includes scaffolding and VAT, and whether the old gutter is taken away. Afterwards the site is left tidy and the old gutter leaves with us. A short decision rule helps too: choose uPVC where cost and simplicity lead, aluminium where a crisp modern line matters and weight must stay low, and cast iron where the building's age and its listing point that way. Whatever the material, the fall, the bracket spacing and the joints decide how well the run drains in heavy rain.
