How to Price Composite Cladding Installation: Labour, Materials and Margin Guide

Summary

Composite cladding — wood-polymer composite (WPC) boards made from a wood-fibre and polymer blend, usually with a co-extruded UV-stable cap — has become a mainstream choice for re-cladding extensions, garages, garden rooms, dormers and gable ends. It sits alongside timber cladding and render as one of the three realistic external finish options a customer will ask about, and it's increasingly the default recommendation for anyone who doesn't want to repaint or re-oil a wall every few years.

The pricing model for composite cladding surprises a lot of newer installers because the boards themselves are rarely the biggest cost. What actually drives the price is the invisible sub-frame — the treated softwood battens, the breather membrane, the ventilated cavity, the corner trims and window/door reveal detailing — and the labour to get all of that right. A wall clad with premium boards on a badly detailed sub-frame will trap moisture, warp, and fail within a few years regardless of how good the boards themselves are. A wall clad with mid-range boards on a properly ventilated, correctly detailed sub-frame will comfortably outlast the customer's ownership of the house.

The second pricing driver is fire performance, and this is where accuracy matters more than most trades assume. Composite cladding products carry a Euroclass fire rating under BS EN 13501-1, and while the combustible-cladding ban (Building Regulations Regulation 7(2)) only applies to relevant buildings over specific height thresholds — not a typical single-storey rear extension — a professional installer should always know and be able to quote the fire classification of the product they're fitting, particularly close to a boundary where Approved Document B's unprotected area rules apply.

This guide covers material selection, sub-frame design, fixing systems, fire performance, and a worked pricing breakdown for a typical job.

Key Facts

• Capped composite cladding board (co-extruded UV cap) — £28–£55/m² supply
• Uncapped/budget composite cladding board — £18–£30/m² supply; fades, absorbs moisture and surface-degrades faster — flag ⚠ and avoid recommending on a customer-facing quote unless budget is the overriding driver
• Premium large-format composite plank (concealed fix system) — £45–£65/m² supply
• Aluminium/composite trims (corner, starter, J-trim, edge) — £8–£18 per linear metre
• Treated softwood battens (25×38mm or 25×50mm) for the ventilated cavity — £2–£4/m
• Breather membrane (to BS EN 13859-2) — £1.50–£3/m² supply
• Minimum ventilated cavity behind the boards — around 25mm is typical manufacturer guidance for drainage and airflow
• Carpenter/cladding installer day rate — £200–£320/day regional, £260–£400/day London
• Specialist cladding fitting crew (2-person) — £320–£480/day
• Fixings — stainless steel (A2/304) concealed-clip or face-fix screw systems; mild/ungalvanised steel screws will rust and stain the boards within 2–3 years
• Expansion allowance — composite boards expand and contract with temperature; manufacturers specify a gap at board ends and joints, usually a few millimetres per metre run, covered by trims
• Fire classification (Euroclass, BS EN 13501-1) — composite cladding products commonly range from around Class C-s3,d0 up to B-s2,d0 depending on the specific product; always check the manufacturer's fire test certificate before specifying, especially near a boundary
• Combustible cladding ban (Regulation 7(2) of the Building Regulations, as amended) — restricts combustible materials in external walls of "relevant buildings" over 18m in height, lowered to 11m for certain residential buildings with balconies from December 2022; this does not generally apply to a standard house extension, garage or garden room, but the height and use class of the building should always be confirmed before assuming it's out of scope
• Composite cladding lifespan — 25–30 years typical for a capped product with correctly ventilated fixing; manufacturer product warranties commonly run 10–25 years
• Damp detailing at the base — cladding should terminate a minimum of roughly 150–225mm above finished ground level to avoid rising damp and rain splashback
• Installation time — roughly 1.0–1.8 hours per m² for a competent two-person crew on a straightforward single-storey elevation, including battens, membrane and trims; complex reveals, corners and soffits add 20–40% on top

Quick Reference Table

Detailed Guidance

What to ask the customer at quote

1. Existing wall construction — solid masonry (batten direct-fix possible with correct fixings), cavity wall, or timber frame (may already have a breather membrane in place — don't duplicate or bypass it)
2. Access — single storey vs two storey, whether scaffold or tower is needed
3. Colour/finish sample — composite comes in a limited but growing range of woodgrain and solid colours; always show a physical sample, not a screen render
4. Boundary proximity — relevant to fire spread considerations under Approved Document B, particularly on terraced or semi-detached properties
5. Insulation ambition — does the customer want a thermal upgrade as part of the re-clad, or purely a cosmetic/maintenance-free finish?
6. Existing finish being replaced — stripping old render or failed timber cladding adds significant labour and disposal cost; always survey before pricing off a photo

Sub-frame and ventilation — the part that actually takes the time

The boards are the visible 20% of the job; the sub-frame is the invisible 80% that determines whether it lasts.

• Battens and counter-battens — treated softwood battens fixed to the wall (through the membrane) create the ventilated cavity; vertical boards need horizontal battens, and vice versa
• Breather membrane (BS EN 13859-2) — fitted directly to the wall or over insulation before battening; allows moisture vapour out while stopping wind-driven rain in
• Cavity depth — creates airflow behind the boards so any moisture that does get past the cladding can dry out rather than sit against the wall
• Fixing centres — follow the manufacturer's spec for batten spacing (commonly 400–600mm depending on board profile)
• Vermin mesh — fit at the base and eaves of the cavity to stop insects and rodents nesting in the ventilated void

Fixing systems

Two main approaches: concealed clip systems, where boards click into aluminium or composite clips fixed to the battens (cleaner finish, no visible screw heads, slightly more expensive and slower to fit), and face-fix systems, where boards are screwed directly through the face with colour-matched caps or countersunk screws (cheaper, faster, less visually clean). Always specify A2/304 stainless steel fixings — anything less will corrode and streak the boards within a couple of years, and re-doing a job for staining is far more expensive than fitting it correctly the first time.

Fire performance and where it matters

For the overwhelming majority of domestic cladding jobs — a single-storey rear extension, a garage, a garden room, a dormer — the Regulation 7(2) combustible cladding ban simply doesn't apply; it targets "relevant buildings" over 18m (11m for certain residential buildings with balconies), which is multi-storey block-of-flats territory, not a bungalow extension. That said, two things still matter on every job:

1. Approved Document B's unprotected area rules (Part B4) govern fire spread to a boundary regardless of building height, so a wall close to a boundary can have restrictions on the extent of combustible cladding
2. Always hold the manufacturer's Euroclass fire test certificate (BS EN 13501-1) for the specific product being fitted — don't rely on a generic "composite is fire safe" assumption; different products and different core densities test differently

Composite vs timber vs render — when to recommend each

Recommend timber cladding when: the customer wants a natural, weathering look and is happy with periodic oiling/staining, or the property is in a conservation area with material restrictions.

Recommend render when: the wall needs a seamless, monolithic finish (particularly on complex geometry with lots of corners) — see render types for the render system comparison.

Recommend composite cladding when: the customer wants a low-maintenance, consistent-colour finish that won't need repainting, particularly on a modern extension or garden room elevation. It's directly comparable in maintenance philosophy to composite decking — see composite fencing panels guide for the same wood-polymer composite material used in fencing panels, and note the fixing-system logic (clip vs face-fix, expansion allowance) carries across both applications.

Common pitfalls

• Fixing straight to a solid wall without a cavity — traps moisture behind the boards; always batten off with a ventilated gap, even on masonry
• Wrong fixing screws — mild steel corrodes and streaks the boards within 2–3 years
• No expansion gap at joints — boards buckle and bow in summer heat if fitted tight
• Cladding taken down to ground level with no clearance — wicks damp up into the base of the boards
• Quote omits reveals, corner trims and soffit detailing — these are where most of the labour time actually goes; a quote priced purely on wall area under-recovers badly

Pricing breakdown for a typical job

A 30m² single-storey extension gable and return wall, capped composite cladding on treated softwood battens over existing brickwork, with corner trims and window/door reveal detailing:

Round to £5,300. Per-m² works out at £177 — above the existing-wall simple-elevation tier (£90–£140/m²) but below the full complex-elevation tier (£220–£320/m²), reflecting the corner trim and window/door reveal detailing this job includes, without the multiple corners and soffits that would push it into the complex-elevation band.

Frequently Asked Questions

How does composite cladding compare to timber cladding for cost and maintenance?

Composite is roughly 1.5–2× the material cost of mid-range softwood timber cladding, but needs no oiling, staining or repainting — timber cladding typically needs recoating every 2–4 years to hold its colour, which is a recurring cost the customer bears long after your job is finished. Over a 20-year ownership period, composite's total cost of ownership is often lower despite the higher install price.

Do I need a fire-rated product for a house extension cladding job?

Not in the sense of the Regulation 7(2) combustible cladding ban — that only applies to relevant buildings over 18m (11m for certain residential buildings). But you should still know and be able to state the Euroclass fire classification of the specific product you're fitting, particularly if the elevation is close to a boundary, where Approved Document B's unprotected area rules apply regardless of the building's overall height.

Can composite cladding go straight onto rendered brick without battens?

No — always create a ventilated cavity with battens, even over a sound masonry wall. Direct-fixing traps moisture behind the boards with nowhere to escape, which is one of the most common causes of premature cladding failure, board swelling at fixing points, and mould growth on the wall behind.

How long does capped composite cladding actually last outdoors?

25–30 years for a correctly ventilated, properly fixed installation with a quality capped product. Uncapped or budget composite has a materially shorter service life — often 10–15 years before visible fading, surface degradation or moisture absorption becomes a problem — which is why it's worth flagging clearly on any quote where a customer is tempted by the lower material price.

Regulations & Standards

• Building Regulations Part B (Approved Document B, Volume 1 & 2) — fire safety; Section B4 governs external fire spread and unprotected area/boundary distance rules

• Building Regulations Regulation 7(2) — restricts combustible materials in external walls of relevant buildings over 18m (11m for certain residential buildings with balconies, from December 2022)

• BS EN 13501-1 — Fire classification of construction products and building elements (Euroclass system)

• BS EN 15534-5:2014 — Composites made from cellulose-based materials and thermoplastics (wood-polymer composite/WPC or natural fibre composite/NFC): Part 5 specifies cladding profiles and tiles specifically (Part 4 covers decking profiles and tiles; Part 1 covers the underlying test methods) — confirm the specific product's compliance sheet cites Part 5, not Part 4

• BS EN 13859-2 — Flexible sheets for waterproofing: breather membranes for wall cladding

• Building Regulations Part C — Site preparation and resistance to contaminants and moisture; relevant to cavity and ventilation detailing behind cladding

• Town and Country Planning (General Permitted Development) (England) Order 2015 — permitted development for external material changes on extensions

• Approved Document B: Fire safety — gov.uk

• Banning the use of combustible materials — guidance — gov.uk

• BS EN 13501-1 — Fire classification of construction products — BSI

• Timber Decking and Cladding Association (TDCA) — UK trade body for decking and cladding installation guidance

• Planning Portal — householder permitted development — external material change guidance

• cladding fire safety — post-Grenfell cladding fire classification and regulatory context

• render types — external render comparison as an alternative finish

• composite fencing panels guide — same wood-polymer composite material used in fencing

• garden room pricing guide — common application context for composite cladding on new structures