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TPO Roof Cost Calculator

Estimate 2026 UK TPO single-ply membrane roof cost by line item: 1.2/1.5/2.0 mm thickness, mechanically fixed, fully adhered, induction-welded RhinoBond, or ballasted, with PIR insulation, gypsum overlay board, outlets, strip-out, Building Control and skip hire. Real 2026 NFRC and SPRA contractor rates.

TPO Roof Cost Calculator

2026 UK TPO single-ply membrane roof cost by line item — 1.2/1.5/2.0 mm thickness, mechanically fixed, fully adhered, induction-welded RhinoBond, or ballasted. Includes PIR insulation, gypsum overlay board, roof outlets, strip-out, Building Control and skip removal. Real 2026 NFRC and SPRA contractor rates.

Estimated TPO roof cost
£291,720
Range: £247,962 – £350,064
membrane + strip + PIR + overlay + outlets + Building Control + skip
Membrane installed
£171,600
Strip-out
£39,600
PIR insulation
£48,000
Overlay board
£28,000
Outlets
£320
Skip removal
£4,200

What this calculator estimates

This calculator gives you a line-by-line 2026 UK installed price for a TPO single-ply membrane roof. Whether you are renewing a 50 m² residential dormer flat, a 350 m² retail-strip roof in Manchester, or a 2,500 m² distribution warehouse in Daventry, the calculator follows the line-item structure NFRC and SPRA member contractors use on real tenders:

  • TPO membrane — 1.2 mm, 1.5 mm or 2.0 mm, mechanically fixed, fully adhered, induction-welded RhinoBond or ballasted
  • Strip-out — removing the existing membrane, insulation and fixings
  • PIR insulation — 100 mm, 150 mm or tapered PIR for fall to outlets
  • Gypsum overlay board — Knauf Roof Deck Board, Fermacell or equivalent
  • Outlet count — internal rainwater outlets and overflow scuppers
  • Building Control, skip hire, weekend premium and additional labour

A £1,450 minimum call-out fee applies in most UK markets even on small jobs, because TPO requires a 2-person crew with a hot-air welder, induction welder (for RhinoBond), and scaffolding or MEWP hire.

How to use it

  1. Enter roof area in m² (use the building footprint if the roof is fully flat).
  2. Pick membrane thickness — 1.2 mm for light residential, 1.5 mm for commercial standard, 2.0 mm for premium guarantee.
  3. Pick fixing method — mechanically fixed (baseline), fully adhered (+18%), induction-welded RhinoBond (+10%) or ballasted (−15%).
  4. Pick PIR insulation — none (overlay), 100 mm, 150 mm or tapered.
  5. Set scope — spot repair (20%), partial replace (50%) or full re-roof (100%).
  6. Set storey count — single-storey 1.0x, two-storey 1.18x, three-storey or higher 1.40x.
  7. Set access difficulty — easy (driveway frontage) 1.0x, moderate (rear garden) 1.10x, hard (terraced, scaffold required) 1.30x.
  8. Enter outlet count and toggle strip-out, overlay board, Building Control, skip hire, weekend premium and any extra labour hours.

Typical 2026 UK TPO roof cost ranges

These ranges reflect 2026 nationwide pricing from the NFRC State of the Roofing Industry Report, SPRA Member Survey and Q1 2026 quotes from London, Manchester, Birmingham, Glasgow and Bristol.

TPO system (200 m², single-storey, moderate access)2026 installed price
1.2 mm mechanically fixed, 100 mm PIR, strip-out£10,500 – £16,500
1.5 mm mechanically fixed, 100 mm PIR, strip-out£14,500 – £22,500
1.5 mm fully adhered, 120 mm PIR, overlay board£17,500 – £26,500
1.5 mm induction-welded RhinoBond, 120 mm PIR£16,500 – £24,500
2.0 mm mechanically fixed, 150 mm PIR, overlay board£18,500 – £29,000
1.5 mm ballasted (no fixings through membrane)£11,500 – £17,500
Tapered PIR for fall, 1:60add £18 – £32 per m²
Gypsum overlay board (Knauf Roof Deck or Fermacell)add £12 – £18 per m²
Internal rainwater outlet, retrofit£280 – £420 each
Overlay (no strip-out), 1.5 mm over existing£9,500 – £15,500

Add 18 percent for two-storey, 40 percent for three-storey or higher. Add 10 to 30 percent for moderate to hard access. Add 25 percent for weekend or out-of-hours working.

Cost drivers

Membrane thickness and BBA tier. Sika Sarnafil S-327 in 1.5 mm and 2.0 mm is the most-specified TPO system in UK commercial roofing 2026. Bauder Thermofol U15 (1.5 mm) and U20 (2.0 mm) and IKO Spectraplan T are next. Renolit Alkorplan F is widely used in retail-park new-build. The 2.0 mm cap layer is roughly 50 percent thicker than 1.5 mm and carries a 30 to 50 percent material premium, with labour cost similar.

Fixing method. Mechanically fixed is the fastest install (400 to 600 m² per day for a 2-person crew) and cheapest, but is prone to flutter under high wind and has visible fastener rows. Fully adhered (water-based or low-VOC bonding adhesive) is monolithic, has the best aesthetic on visible flat roofs and the highest wind uplift, but costs 15 to 20 percent more and installs at 250 to 350 m² per day. RhinoBond eliminates the linear seam weakness while keeping mechanical-fixing speed. Ballasted is a legacy approach — fast on big roofs, but adds 60 to 80 kg per m² of dead load that the structure must accept under BS EN 1991-1-1.

Insulation and overlay board. PIR is the dominant substrate. Two layers staggered prevent thermal bridging through joints. Gypsum overlay board (Knauf Roof Deck Board, Fermacell) protects the TPO from PIR facer punctures and is required by Sika, Bauder, IKO and Renolit for 20+ year BBA-backed guarantees. HD PIR overlay is a cheaper alternative used in lower-guarantee tiers.

Strip-out versus overlay. Approved Document A and structural calculations per BS EN 1991-1-1 permit overlay of one existing layer with new TPO if the deck is structurally sound. Overlay is 25 to 35 percent cheaper than strip-out and reduces skip volume. Strip-out is mandatory if the existing assembly is wet, has interstitial condensation damage, or if a structural engineer requires deck inspection.

Outlets and penetrations. Internal cast-iron outlets (HepworthRain, Aquaflow, Marley Alutec) are £280 to £420 each installed retrofit. Overflow scuppers, pipe boots and AHU curb flashings add £160 to £400 each. Reusing existing penetrations is cheaper than relocating but limits PIR fall design.

Storey, access and MEWP logistics. A single-storey commercial roof with driveway access is the cheapest install. Two-storey adds 18 percent for scaffold and hoist time. Three-storey-or-higher adds 40 percent for tower scaffold or MEWP rental at £1,200 to £2,400 per day plus delivery. Scaffold hire is governed by the Construction (Design and Management) Regulations 2015 and the Work at Height Regulations 2005.

TPO chemistry and what makes a good UK product

TPO (thermoplastic polyolefin) is a blend of polypropylene and ethylene-propylene rubber, reinforced with a polyester scrim. For UK climate (moderate temperature, low UV index, high rainfall, coastal salt aerosol), quality varies between manufacturers based on:

  • UV stabilisers: hindered amine light stabilisers (HALS) and UV absorbers extend cap-layer life. Lower-tier products fade and chalk within 10 to 14 years.
  • Scrim weight: 800 to 1,500 denier polyester reinforcement. Heavier scrims resist puncture from foot traffic and maintenance.
  • Plasticiser content: TPO uses no plasticisers (unlike PVC), so it does not embrittle over time the way old PVC membranes do.
  • Salt-aerosol resistance: coastal sites (Aberdeen, Cornwall, Norfolk, Welsh coast) need confirmed salt-fog tested membrane. Sika Sarnafil S-327 and Bauder Thermofol U15 hold BS EN ISO 9227 salt-spray test data.

For a 20+ year UK service life, specify a BBA-certified manufacturer (Sika, Bauder, IKO, Renolit, Holcim) with a 20-year insurer-backed guarantee.

UK code references and authority sources

  • Approved Document A — structural safety, including roof dead and live loads
  • Approved Document B — fire safety, including roof construction and BROOF(t4) classification
  • Approved Document C — site preparation and resistance to moisture
  • Approved Document L1B — conservation of fuel and power in existing dwellings (U-value 0.18 W/m²K)
  • BS 6229 — Flat roofs with continuously supported flexible waterproof coverings: Code of practice
  • BS EN 13956 — Flexible sheets for waterproofing — Plastic and rubber sheets for roof waterproofing
  • BS EN 16002 — Flexible sheets for waterproofing — Determination of the resistance to wind load
  • BS EN 13501-5 — Fire classification of construction products: roof tests (BROOF(t4))
  • NHBC Standards Chapter 7.2 — Flat roofs with continuously supported coverings
  • NFRC Technical Bulletin TB13 — Single-ply roofing application guidance
  • SPRA Design Guide for Single-Ply Roofing — 2024 edition
  • Work at Height Regulations 2005 and CDM Regulations 2015 — site safety
  • BBA Agrément Certificate — third-party-verified system performance, required for NHBC and Building Control acceptance

When TPO is the wrong choice for a UK flat roof

  • Listed Buildings and Conservation Areas — bright white TPO is often refused. Use a darker grey membrane or, better, traditional lead or zinc sheet.
  • Pitches above 10 degrees — water-shedding zinc, lead, slate or tile is more appropriate; TPO is designed for pitches below 5 degrees.
  • Garden offices and small domestic flats below 30 m² — EPDM in one-piece formats (Firestone RubberCover, ClassicBond) is faster and cheaper.
  • Heritage zones with archaeological constraint — minimum-disturbance overlay with traditional materials is preferred.

Bidding strategy and red flags

Always get three written tenders that itemise membrane brand, thickness, BBA reference, guarantee tier, fixing method, insulation U-value, overlay board and outlet count. A tender that says “TPO roof, £X per m²” with no line items is a red flag. Confirm:

  1. The contractor is on the manufacturer’s registered-installer list (required for the 20+ year insurer-backed guarantee).
  2. The tender includes wind-uplift design per BS EN 1991-1-4 for your postcode and exposure zone.
  3. The tender lists Building Control or Competent Roofer self-certification, skip hire and MEWP mobilisation as separate line items.
  4. The tender includes a 2-year workmanship warranty on top of the manufacturer’s material guarantee.
  5. The tender identifies the on-site supervisor and confirms CDM 2015 Principal Contractor role assignment.

For deeper estimating, also use our flat roof replacement cost calculator, built-up roof cost calculator and roof coating cost calculator to compare TPO against EPDM, mod-bit and built-up alternatives at your specific size and exposure.

Frequently asked questions

How much does a TPO roof cost per m² in the UK in 2026?
In the UK, 1.5 mm mechanically fixed TPO installs at £70 to £110 per m² all-in for a typical commercial or residential flat roof, including strip-out, 100 mm PIR insulation, gypsum overlay board, outlets, Building Control and skip hire. 1.2 mm drops to £60 to £90 per m². 2.0 mm with 30-year guarantee climbs to £95 to £140 per m². Fully adhered systems add 15 to 20 percent. A 200 m² 1.5 mm mechanically fixed install with 100 mm PIR runs £14,500 to £22,500 in 2026 NFRC and SPRA member survey pricing. Source: NFRC State of the Roofing Industry Report 2026; SPRA Single-Ply Roofing Association Member Survey Q1 2026.
What is the difference between 1.2 mm, 1.5 mm and 2.0 mm TPO?
The figure refers to total membrane thickness. 1.2 mm is the entry tier for residential porches and garages with 10 to 15-year warranties. 1.5 mm is the commercial industry standard from Sika Sarnafil S-327, Bauder Thermofol U15, FATRA Fatrafol 810 and IKO Spectraplan T, with 20-year manufacturer guarantees. 2.0 mm is the premium tier for warehouses with heavy maintenance traffic, hail-prone regions and 25 to 30-year non-pro-rated guarantees. Reinforced polyester scrim is similar across thicknesses, but the cap layer above the scrim is thicker, giving more puncture resistance and longer UV life. Source: Sika Sarnafil S-327 technical data sheet 2026; Bauder Thermofol guarantee schedule.
TPO versus EPDM — which is better for a UK flat roof?
TPO is white (high solar reflectance and BBA-certified Cool Roof eligibility), heat-weldable, scrim-reinforced and 30 to 40 percent cheaper than EPDM in 1.5 mm at 2026 UK prices. EPDM (Firestone RubberCover, ClassicBond, Permaroof) is black, splice-taped, lasts 30 to 40 years versus 20 to 25 for TPO, and is the dominant choice for small UK domestic flat roofs. For visible commercial roofs requiring Energy Star Cool Roof or Part L compliance via membrane reflectance, TPO wins. For small porches, dormers and garage flats where lap-and-rinse install is needed, EPDM wins. Both can be ballasted, mechanically fixed or fully adhered.
Is TPO BBA-certified in the UK?
Yes. Sika Sarnafil S-327, Bauder Thermofol U15, IKO Spectraplan T, FATRA Fatrafol 810 and Renolit Alkorplan F all hold current BBA Agrément Certificates with declared service life of 30+ years when installed per the certificate conditions. BBA certification covers wind-uplift testing per BS EN 16002, fire-classification per BS EN 13501-5 (BROOF(t4)), and durability per BS EN 1297. Building Control will accept BBA-certified systems without further testing. Source: BBA Agrément Certificate database; NHBC Standards Chapter 7.2.
What is RhinoBond induction welding?
RhinoBond is a Holcim Elevate (formerly Firestone) and Versico mechanical attachment system that uses heat-activated plates fixed through the insulation, then induction-welded to the underside of the TPO at each fastener location. The system eliminates the linear seams at fastener rows (the typical weak point of mechanically fixed systems) and reduces membrane flutter under wind uplift per BS EN 16002. Cost adds 8 to 12 percent over standard mechanical fixing but delivers a 60 to 100 percent uplift performance bump under FM Global 4470 testing. Best suited for exposed coastal sites (Scottish islands, Cornwall, North Norfolk), tall buildings, and re-roofing on existing PIR. Source: Holcim Elevate RhinoBond technical specification 2026.
Do I need PIR insulation under TPO?
For Building Regulations Approved Document L1B compliance on existing dwellings, a flat roof renewal must achieve a U-value of 0.18 W/m²K or better. 100 mm PIR (Kingspan TR27, Celotex GA4000, Recticel Powerdeck F) achieves approximately 0.22 W/m²K — a 120 mm or 150 mm board is required to hit 0.18. Tapered PIR (1:60 fall to outlets) is required when the existing deck has no built-in slope. PIR alone runs £20 to £35 per m² installed for 100 to 150 mm. NHBC Chapter 7.2 requires PIR minimum where the flat roof forms part of a habitable area. Source: Approved Document L1B 2024; NHBC Standards Chapter 7.2.
How long does a 1.5 mm TPO roof last in the UK?
Industry-standard 1.5 mm TPO from Sika Sarnafil, Bauder, IKO and Renolit carries 20 to 25-year material and labour warranties under BBA conditions. Field service life is 25 to 30 years for fully adhered, 22 to 28 for mechanically fixed, and 18 to 25 for ballasted systems in UK climate (moderate temperature, low UV index compared to Mediterranean). UV degradation is the limiting factor — micro-cracking exposes the scrim and the membrane fails. Coastal exposure (salt aerosol) reduces life by 10 to 15 percent. Annual inspections and biennial cleaning extend service life. Recoating with PMMA (polymethyl methacrylate) liquid or acrylic coatings (additional £14 to £28 per m²) extends life by 10 to 15 years.
Does a UK TPO flat roof need Building Control approval?
Full strip-out and renewal triggers a Building Control notification under Approved Document L1B if more than 25 percent of the roof area is renewed, and under Approved Document C for waterproofing. A Competent Roofer scheme installer (Sika, Bauder, IKO and Renolit registered installers) can self-certify under the Building Control compliance route, removing the LA Building Control fee. Listed Buildings, Conservation Areas and properties within National Parks may require additional consent — check with the local Conservation Officer before specifying a bright white membrane that may be visible from public realm. Source: Approved Document L1B 2024; Approved Document C 2025; Competent Roofer scheme rules.

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