How to Price a Gutter Replacement: Half-Round vs Square-Line, uPVC vs Aluminium, Labour and Margin Guide

Quick Answer: Replacing the rainwater goods on a typical UK 3-bed semi (around 18–22m of gutter, 8–10m of downpipe) prices £680–£1,100 in uPVC, £1,400–£2,400 in seamless aluminium, and £2,200–£3,800 in cast iron in 2026. Pricing is driven by linear metres, scaffold or tower hire, profile choice (half-round, square-line, ogee, deep-flow), and the condition of the fascias and soffits behind. BS EN 12056-3 governs gutter sizing — undersizing on a re-roof or extension is a discharge claim waiting to happen.

Summary

Gutter replacement is one of those jobs that looks deceptively simple on a quote sheet — pull the old plastic off, clip new plastic on, done. In reality, the price spread between a budget uPVC swap and a seamless aluminium replacement is 3:1, and the labour content is dominated by access, not by the gutter itself. A two-storey semi with safe ladder access, hopper-fed downpipes, and intact fascias is a half-day job for a two-person crew. The same semi with a wraparound bay, no scaffold-able front, and rotted fascia boards becomes a 3-day project at four times the labour cost.

The 2010s shift from press-fit uPVC to seamless aluminium has changed the high-end of the market. Aluminium gutters are roll-formed on-site to the exact run length, eliminating joints (and the leaks that come with them), and now carry 25–30 year manufacturer guarantees. Cast iron remains the regulatory choice for listed buildings and most conservation areas — the planning officer will reject uPVC reinstatement on a Grade II property in a heartbeat.

The pricing trap most new roofers fall into is quoting the gutter run only, then discovering on day 1 that the fascias are spongy with rot and the soffits need stripping. Always inspect (or price-with-PC-sum) the fascia condition before committing to a fixed price. A £40/metre fascia replacement on a 22m run is another £880 on the job and easily wipes out the margin on the gutter itself.

Key Facts

Quick Reference Table

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Property type Gutter run Downpipe run uPVC fitted 2026 Aluminium seamless 2026 Cast iron 2026
1-bed bungalow 16–20m 4–6m £480–£720 £1,000–£1,500 £1,600–£2,400
2-bed terrace (rear only) 8–12m 4–6m £280–£480 £580–£900 £900–£1,400
3-bed semi (front + back) 18–22m 8–10m £680–£1,100 £1,400–£2,400 £2,200–£3,800
3-bed detached 22–28m 10–14m £820–£1,400 £1,800–£2,900 £2,800–£4,800
4-bed detached 28–36m 12–18m £1,100–£1,800 £2,400–£3,800 £3,800–£6,200
5-bed / large period 36–50m 16–24m £1,500–£2,400 £3,200–£5,200 £5,200–£8,800
Bay window addition +6–10m +2–4m +£220–£420 +£480–£820 +£800–£1,400
Conservatory addition +8–14m +2–4m +£280–£560 +£600–£1,100 (unusual on conservatories)
Fascia replacement add-on per metre — +£28–£42 +£28–£42 +£28–£42

Detailed Guidance

Profile selection — capacity vs appearance

The most common error on residential gutter replacement is undersizing the profile relative to the roof area being drained. BS EN 12056-3 sets a 75mm/hr design rainfall for most of England (slightly higher in the West Country and Scotland). The profile must carry that flow without overtopping.

Profile Approx capacity (l/s) Max roof area drained (single outlet)
76mm Mini half-round ~1.0 ~30m²
112mm Half-round (standard) ~2.4 ~75m²
117mm Square-line ~2.7 ~85m²
125mm Deep-flow / Hi-Cap ~3.6 ~120m²
150mm Deep half-round ~4.5 ~160m²
122mm Ogee ~3.0 ~95m²

For most 3-bed semis, the front pitch is around 30–40m² per side, the back pitch similar. A standard half-round on a single front-corner outlet will just about cope; a deep-flow or square-line is comfortable. If the customer is replacing because of overtopping in heavy rain, recommend the next profile up — like-for-like 112mm half-round may not solve the problem.

For the rear of a property with a long single run (e.g. a mid-terrace garden block of 12m+), use a deep-flow profile or split the run with a centre outlet.

uPVC vs aluminium vs cast iron — the choice for the customer

uPVC is the budget default. 25-year colour guarantees are now standard from the major brands (FloPlast, Brett Martin, Polypipe). It's lighter than aluminium, easier to handle on a ladder, and fits with simple rubber-seal joints. The downsides are joint leaks (every 4m there's a connector that can fail), UV-driven brittleness over 15–20 years (especially on south-facing runs), and unrepairable cracks if a ladder is dropped against it. For a homeowner replacing a 1980s system in a non-conservation street, uPVC is the right answer 80% of the time.

Seamless aluminium is roll-formed on-site from a coil of pre-coated alloy. The gutter is one continuous length per elevation (only joined at corners), so leak points are dramatically reduced. Manufacturer warranties of 25–30 years are typical. It costs 2–2.5× as much as uPVC fitted, but on a long-life-of-house basis it's cost-neutral by about year 25. Best for 4+ bed properties, awkward roof geometry, or anywhere the customer wants "fit and forget" rather than "replace in 20 years".

Cast iron is the regulatory choice for listed buildings, conservation areas where the planning condition requires it, and high-end heritage restoration. Genuine cast iron is heavy (2-person lift on every length), expensive, and needs periodic painting. Cast aluminium "look-alike" gutter (e.g. Cascade by Alumasc, Hargreaves Aris) is now widely accepted by conservation officers as a substitute — same profile and bead detail, fraction of the weight, no painting. Always check with the conservation officer before quoting cast aluminium on a Grade II property.

What goes wrong with the existing system — the inspection

Before quoting, walk every gutter run from a ladder or access tower and check:

If the fascia is rotten, price for fascia replacement (typically £28–£42/m supplied and fitted as part of a gutter job, less as a standalone). New fascias commonly come with new soffits as a package.

Access — the dominant cost driver

For a single-storey bungalow or low rear wall, ladder access is fine. Two-person crew, one on the ladder and one feeding lengths up. £14–£18/m labour is realistic.

For a two-storey semi gable, a tower (3.5–6m) is preferred over a ladder for safety and productivity. Tower hire is £120–£220/week and turns a 2-day job into 1 day.

For a full perimeter on a two-storey detached, scaffold the awkward elevations. £180–£320/week per gable for a basic edge-protection scaffold. The customer often baulks at the scaffold cost — explain that the alternative is 3 days of slow ladder work plus the Working at Height Regulations 2005 risk exposure.

For high gables, dormers, or three-storey town houses, full scaffolding is non-negotiable and adds £600–£1,400 to the job.

Gutter sizing for extensions and conversions

When pricing a new build, extension or conservatory, the gutter sizing must satisfy BS EN 12056-3 for the actual roof area drained. The common error is to fit the same profile as the existing house regardless of the new catchment. If a new garden room of 35m² discharges through a single 68mm round downpipe to the existing 112mm gutter, that single outlet is at the upper limit and any moss build-up will overtop.

Calculate flow as: roof plan area (m²) × design rainfall (l/s/m²) × allowance for slope. For a 75mm/hr design rainfall and a 30° pitched roof, plan area × 0.0234 gives litres/sec. Compare to the profile capacity table above, and choose the next profile up.

Downpipes — outlets, hoppers and connections to drainage

Standard 68mm round (uPVC) or 65mm square downpipes fit most domestic situations. For larger catchments or commercial work, 80mm or 110mm downpipes are used.

The downpipe must discharge into either:

Always include the downpipe shoe and any required swan-neck offset in the quote — these are easy to forget and add £30–£80 to the materials bill.

Frequently Asked Questions

How much does it cost to replace gutters on a 3-bed house in the UK?

For a typical 3-bed semi in 2026: £680–£1,100 in uPVC, £1,400–£2,400 in seamless aluminium, £2,200–£3,800 in cast iron. The price covers around 18–22m of gutter and 8–10m of downpipe, plus outlets, stop-ends, brackets, and labour. If the fascias are rotten and need replacing at the same time, add £28–£42 per metre.

Is seamless aluminium worth the extra cost over uPVC?

Yes if the customer plans to stay 15+ years or values "fit and forget" reliability. Aluminium is roll-formed on-site as one continuous length, so the joint leaks that plague uPVC after 15 years are eliminated. The 25–30 year manufacturer warranty is real, and there's no UV brittleness. The break-even is around year 22–25 in pure replacement cost terms. For shorter ownership horizons or budget-driven replacements, uPVC is the right answer.

Do I need scaffolding to replace gutters?

Working at Height Regulations 2005 applies to all work above 2m. Below 2m, ladder access is permitted with the right risk assessment. Above 2m, you should be using either a properly footed ladder with a second person, an access tower, or scaffold. For productivity (and to comply with HSE expectations on professional work), a tower is the typical answer for a two-storey semi gable, scaffold for whole-perimeter work on a detached property.

Can I fit cast aluminium gutter on a Grade II listed building?

Often yes, but always confirm with the conservation officer first. Cast aluminium "look-alike" gutter (Cascade, Hargreaves Aris, etc.) is widely accepted as a substitute for true cast iron because it preserves the bead profile and shadow detail. True cast iron is sometimes specified for Grade II* and Grade I properties. Get the planning condition wording in writing before pricing — a £4,000 overrun for re-doing the wrong material is not a conversation you want.

Why is my gutter overflowing in heavy rain even though it's not blocked?

Almost always undersizing or insufficient outlets. A long run with a single corner outlet, draining a steep pitched roof, will overtop in any heavy storm. Either upsize the profile (move from 112mm half-round to 125mm deep-flow), add a central outlet, or fit running outlets at the gutter low points. BS EN 12056-3 sets the design rainfall — if the existing system was sized for a shallower roof or smaller area, replacement is the moment to fix it.

Regulations & Standards