Guttering Repair & Cleaning

Blocked or leaking gutters are a common cause of damp in UK homes.¹ Water overflowing from a blocked gutter saturates the wall below, and a poorly sealed joint can drip onto a fascia board for years before anyone notices. The good news is that most gutter problems are straightforward to diagnose and cheap to fix, often by a competent DIYer in an afternoon.

This guide covers the four main failure modes, how to spot them, the repair options for each, and when full replacement makes more sense than patching.

Common Causes of Gutter Problems

Blockages are the most frequent issue. Leaves, moss, and debris build up in the gutter channel and block the downpipe entry, causing water to back up and overflow. Gutters typically need clearing at least once a year, after autumn leaf fall, and more often if you have overhanging trees.²

Sagging happens when gutter brackets fail, rust, or pull away from a rotten fascia. A sagging section holds standing water and pulls the adjacent joints apart over time.

Leaking joints develop when the rubber seal inside a push-fit uPVC joint degrades with age or when a bolted cast iron joint loses its putty seal. Dripping at a joint during rain is the telltale sign.

Cracks and splits in uPVC guttering are caused by UV degradation, frost damage, or impact. uPVC becomes brittle over time; a heavy branch or a carelessly placed ladder can crack a section. Cast iron can crack through corrosion or frost if standing water is not cleared.

How to Diagnose

You do not always need to be on a ladder to find the problem:

• Watermarks on the wall, a vertical brown stain on render or brickwork below the gutter line suggests overflow or a dripping joint.
• Damp patches on the internal wall, persistent damp at first-floor level that doesn’t correlate with condensation often traces back to gutter overflow saturating the cavity or external leaf.
• Green or black staining on the fascia, algae growth on timber fascias below the gutter indicates persistent dripping, usually from a joint or crack.
• Overflow during rain, watch the gutters during moderate rain. If water pours over the edge rather than flowing to the downpipe, there is a blockage or the gradient is wrong.²
• Downpipe check, pour a bucket of water into the gutter at the highest point and watch whether it reaches the downpipe outlet within a few seconds. Slow travel means blocked gutter or insufficient fall.²

DIY Cleaning: Step-by-Step

Cleaning gutters is safe for most householders with the right ladder and basic precautions. Use a ladder made to EN 131, the current standard for portable ladders (check the label on the stile).³ Set it at a 75° angle: 1 unit out for every 4 units up.⁴

1. Set up the ladder safely against the wall, not against the gutter itself (which can be damaged). Use a standoff bracket to keep the ladder away from the wall and guttering.
2. Scoop out debris using a gutter scoop or an old plastic trowel. Work from the end furthest from the downpipe toward it, not away from it. Bag the debris as you go rather than letting it fall.
3. Flush with water using a hosepipe or garden sprayer. Check the flow is reaching the downpipe outlet and moving freely. Standing water after flushing indicates a low spot (sagging) or blocked downpipe.
4. Clear the downpipe by feeding a drain rod gently from the top or by flushing from a higher point. A blocked downpipe often clears easily; if it doesn’t, the blockage may be at the shoe (the bottom bend) or in the underground drain, try clearing from the bottom first.
5. Check joints and brackets while you’re up there. Look for gaps at push-fit joints, loose or missing brackets, and any visible cracks in the gutter channel.

Safety note: never overreach from a ladder.⁴ Move the ladder along rather than stretching sideways. On a two-storey house, if you are not confident working at height, it is worth paying a professional.

Repair Options

Gutter sealant (sold under various names, gutter seal, gutter mastic, lap joint sealant) is the go-to product for minor leaks. Apply to a clean, dry surface. Most need time to cure before they are fully waterproof, so check the curing time on the cartridge before relying on a repair in rain.

Professional Cleaning and Repair Costs

Some companies now use vacuum gutter cleaning from the ground using a telescopic pole with a camera head, no ladder required, and common for two-storey work. Prices are usually similar to ladder-based cleaning.

uPVC vs Cast Iron vs Aluminium

As a guide to supply prices in September 2026, a 4m length of FloPlast 112mm uPVC half-round gutter cost £10.50 at Wickes, about £2.60 per metre before brackets and fittings.⁵ A 1.83m length of primed 115mm cast iron half-round gutter cost £47.37 plus VAT from Rainclear Systems, about £31 per metre with VAT.⁶ A 3m length of 115mm aluminium half-round gutter in matt black cost £78.63 plus VAT from the same supplier, also about £31 per metre with VAT.⁷⁸ (2024 price, brought to 2026)

uPVC is the default choice for most modern UK houses and is the cheapest to buy and install. It does not rust, requires no painting, and sections are easily replaced. However, it degrades in UV over decades, and Historic England does not generally accept wholesale replacement in uPVC on listed and other designated buildings.⁹

Cast iron is the original material and still the best choice for Victorian and Edwardian properties, particularly in conservation areas or if you want to maintain the character of the building. It must be repainted every few years to prevent rust; with that maintenance, cast iron can last far longer than modern replacement materials.⁹ On a listed building, Historic England expects any new sections to match the original profile and material.⁹

Aluminium guttering, particularly seamless or half-round aluminium, sits between the two: lighter than cast iron, longer-lived than uPVC, and available in profiles that can mimic cast iron. It does not rust and can be painted. Historic England accepts powder-coated or heavy cast aluminium on some historic buildings where like-for-like replacement is not possible.⁹

When to Replace Rather Than Repair

Repair is almost always cheaper than replacement, but there are situations where full replacement is the better call:

• uPVC guttering that is visibly degraded (chalky, brittle, multiple cracks), patching will fail quickly
• Cast iron with significant rust through the metal wall rather than surface rust
• Fascia boards that have rotted, which require replacement before new guttering can be fixed
• Multiple failed joints across an entire run, at this point, the rubber seals have all degraded and replacement is more economical than re-sealing each joint
• Guttering that does not meet current capacity for heavy rainfall (common in older properties with undersized half-round or ogee profiles, consider uprating to 115mm or 125mm profiles)

Replacing guttering like for like does not normally need a Building Regulations application. Nor does it need planning permission: works of maintenance that do not materially affect the external appearance of a building are not development.¹⁰ Changing the profile or material is different on a listed building, where it may need listed building consent, and in a conservation area covered by an Article 4 direction; check with your local authority before ordering materials.⁹