Most UK homes have plastic (PVC) gutters, usually half round, square, ogee or a deep flow profile. Older homes often have cast iron, and some have aluminium or steel. Some older buildings also have hidden gutters behind parapet walls and valley gutters between roof slopes, which are harder to see and to clear.
In this guide
What are the common gutter shapes?
Half round, square, ogee and deep flow. The shape affects how much water the gutter carries and how easy it is to clean.
- Half round. A simple curved channel. Very common on houses and bungalows.
- Square. A flat-bottomed, square-edged channel. Common on newer homes.
- Ogee. A decorative profile with a curved, stepped front, seen on many older houses and some newer ones.
- Deep flow. A deeper, wider version of the half round, made to carry more water.
Deep and square gutters can hold more debris before you notice, because it sits lower. Ogee gutters have more corners where silt collects.
Plastic gutters
Light, cheap and widely used. They don’t rust but can sag, crack in the cold or become brittle in sunlight over many years.
PVC gutters are fixed with brackets onto the fascia board and joined with unions containing rubber seals. They are easy to replace in sections. The downsides are that they flex, so a full gutter can sag, and they can’t take the weight of a ladder resting on them; the ladder safety guidance written with the HSE says not to rest a ladder against plastic gutters.
Cast iron gutters
Heavy, strong and long-lasting if they are kept painted. They rust when paint fails and their bolted joints can leak.
Cast iron is common on Victorian and Edwardian homes. It is often fixed with brackets or screwed directly into the fascia or wall. The SPAB advises maintaining cast iron rainwater fittings on old buildings rather than replacing them, including painting to prevent rust. Clearing cast iron gutters is similar to clearing plastic, but they can be deeper and rough inside, so silt clings.
Aluminium and steel gutters
Lighter than cast iron, don’t rust like it, and are often made in long runs with fewer joints.
Aluminium gutters are sometimes formed on site as one continuous length, which reduces joints and therefore leaks. They are stiffer than plastic. Coated steel gutters are also used. Both need the same clearing as any other gutter.
Asbestos cement gutters
Found on some homes and outbuildings built or refurbished before 2000. They should not be scraped, drilled or broken.
These are grey and cement-like. The HSE lists asbestos cement gutters and downpipes among places asbestos can be found. See asbestos cement gutters before anyone works on them.
Hidden, parapet and valley gutters
Some roofs have gutters you can’t see from the ground: behind a parapet wall, between two roof slopes, or in a box at the eaves.
Parapet gutters sit behind a low wall at the edge of the roof. Valley gutters run between two roof slopes, for example on a double-pitched terrace roof (sometimes called a butterfly roof). Box gutters are lined channels built into the roof. They all carry a lot of water, collect leaves and silt, and are hard to inspect from the ground. The SPAB notes that snow should be cleared from parapet and valley gutters with wooden or plastic shovels, so the lining isn’t damaged. Clearing them often needs roof access, which is a job for a roofer or a specialist.
How do I tell what I have?
Look at the colour, feel the weight of a downpipe if you can reach one, and look at the shape of the front of the gutter.
Plastic is smooth, light and usually white, black, brown or grey. Cast iron is heavy, cold and often black, with rust where paint has failed. Aluminium is lighter and often in long, joint-free lengths. Grey, rough, cement-like gutters could be asbestos cement; leave them alone. If you’re booking a gutter clean, say what you think you have; a camera look will confirm it.
Does the gutter type change how it is cleaned?
A little. The method is the same, but deep, decorative and hidden gutters take longer and some need different access.
Half round and square plastic gutters are the most straightforward to clear from the ground. Ogee and deep profiles hold more silt in their corners, so they can need extra passes. Cast iron can be rough inside, so silt clings. Parapet, valley and box gutters may not be reachable from the ground at all. When you book, say what you think you have; a camera look at the start will confirm it.
Key points
- Most UK homes have plastic gutters in half round, square, ogee or deep flow shapes.
- Cast iron is common on older homes and needs painting to prevent rust.
- Never rest a ladder on a plastic gutter.
- Grey cement-like gutters might be asbestos cement.
- Parapet, valley and box gutters usually need roof access.
Quick questions
Which gutter type blocks the most?
It depends more on the roof and trees than the gutter. Deeper and decorative profiles can hold more silt before you notice.
Can a gutter vacuum clean cast iron gutters?
Yes. The nozzle sits in the gutter the same way. Rough, rusty insides can hold silt more tightly.
Should I replace cast iron with plastic?
It depends on the house. On listed and older buildings, cast iron is often kept. Get advice from a roofer or conservation officer.
