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ISO Frame Systems

ISO frame modular building manufactured in UK factory — steel frame structure with insulated panels
ISO Frame Systems

ISO Frame Modular
Buildings UK

Factory-built, stackable to 3 floors, and fully relocatable. ISO frame modular buildings are delivered UK-wide in 8–12 weeks with full Building Regulations compliance as standard.

ISO frame modular building deployed on construction site in Birmingham city centre
Construction Sector

Site Offices & Welfare
Delivered in Days

ISO frame units provide compliant site offices, welfare facilities, and drying rooms for construction programmes. Furthermore, HIAB delivery eliminates the need for mobile cranes, reducing site setup time and cost.

ISO frame welfare unit with insulated panels and external access staircase
Welfare & Amenity

Compliant Welfare Units
Buy or Hire

Purpose-built ISO frame welfare units include canteen, drying room, WC, and changing facilities as standard. In addition, all units meet CDM 2015 welfare requirements and are available on buy, hire, or hire-to-buy terms.

ISO frame modular classroom building installed at UK school site
Education Sector

Modular Classrooms
Ready for September

ISO frame classrooms meet BB103 and Part L requirements for the education sector. Consequently, schools gain additional teaching space within a single half-term, without disrupting existing timetables or site operations.

8–12
Week Programme
3
Floors Stackable
90%
Factory Completed
15yr
Structural Warranty
ISO
9001 · 1090 · 3834
UK
Wide Delivery
What is ISO Frame?

A Proven Steel Frame System
Built for Speed & Flexibility

ISO frame modular buildings use a standardised steel corner casting system — the same connection technology used in global shipping containers. As a result, units are inherently strong, stackable, and transportable without specialist lifting equipment beyond a standard HIAB crane lorry.

Why Traditional Construction Falls Short

Traditional construction programmes routinely overrun on time and budget. Weather delays, subcontractor sequencing, and on-site quality variation all add risk to conventional build programmes. Furthermore, permanent structures cannot be relocated when business requirements change, locking clients into fixed assets regardless of operational need.

How ISO Frame Solves the Problem

ISO frame construction moves 90% of the build process into a controlled factory environment. Consequently, weather, subcontractor availability, and on-site conditions no longer dictate programme delivery. Each unit arrives on site 90% complete, requiring only services connection, external finishing, and snagging before handover.

  • Standardised connections — ISO corner castings enable stacking to 3 floors and rapid HIAB positioning on any prepared surface
  • Factory quality control — ISO 9001, ISO 1090, and ISO 3834 certified manufacturing throughout every stage of production
  • Full relocatability — units can be lifted, transported, and reinstalled at a new site without structural alteration or loss of certification
  • Buy, hire, or hire-to-buy — flexible procurement routes available for single units and large multi-unit programmes

The result: clients across the UK receive a fully compliant, fully fitted ISO frame modular building within 8–12 weeks of order confirmation — with no weather delays and no on-site quality surprises.

ISO frame modular building system — steel corner casting connection detail UK
8–12 Weeks
Order to Handover

ISO frame steel corner casting system — the same technology used in global container logistics

Why ISO Frame

Six Reasons Clients Choose
ISO Frame Construction

Each feature below is engineered specifically for clients who need compliant, high-quality modular buildings delivered faster and with less on-site risk than traditional construction.

8–12 Week Programme

Factory manufacturing runs in parallel with site preparation. As a result, the overall programme is significantly shorter than traditional construction, with handover typically achieved within 8–12 weeks from deposit and confirmed design.

Stackable to 3 Floors

ISO corner castings enable secure stacking to three floors without additional structural steelwork. Furthermore, each floor level is independently certified, enabling phased vertical expansion as your space requirements grow over time.

Fully Relocatable

Every ISO frame unit can be lifted by HIAB, transported on a standard low-loader, and reinstalled at a new site. Consequently, your modular building retains its full residual value and certification regardless of how many times it is relocated across the UK.

Energy-Efficient Envelope

KINGSPAN QuadCore insulated panels achieve wall U-values of 0.16–0.18 W/m²K as standard. In addition, roof insulation delivers 0.11 W/m²K, ensuring Part L compliance and significantly reduced operational energy costs throughout the building’s service life.

90% Factory Completed

Electrical first fix, internal lining, flooring, and joinery are all completed under controlled factory conditions before dispatch. Therefore, on-site installation typically takes just 1–5 days, minimising disruption to adjacent operations and eliminating weather-related programme risk entirely.

Buy, Hire, or Hire-to-Buy

ISO frame units are available on outright purchase, short-term hire, long-term hire, and hire-to-buy agreements. As a result, clients can access compliant modular space without the full capital outlay of a permanent building, with the option to convert hire payments into ownership at any point.

ISO frame welfare unit with KINGSPAN insulated panels — UK site deployment

ISO 9001 · ISO 1090 · ISO 3834 Certified

Every ISO frame modular building is manufactured under triple ISO certification. Furthermore, Constructionline Bronze and SSIP accreditation confirm our commitment to quality, safety, and supply chain compliance across every project.

Configurations

Three Specification Levels.
One Proven System.

Every ISO frame project has different performance requirements. As a result, we offer three specification levels to match your compliance obligations, budget, and programme timeline precisely.

Standard

ISO Frame Standard Specification

Our standard ISO frame specification delivers a fully insulated, electrically wired modular building suitable for offices, welfare, and storage applications. Furthermore, all standard units include KINGSPAN insulated panels, LED lighting, and consumer unit as standard.

Key Inclusions

KINGSPAN insulated wall panels
IP65 LED lighting throughout
PVC double-glazed windows
From £18,000 ex-works
Best for
Site offices, welfare units, storage, temporary accommodation, hire fleet stock
Most Popular
REI60 Fire-Rated

ISO Frame REI60 Specification

Our REI60 specification adds 60-minute fire-rated panels, FD60 fire doors, and enhanced fire detection systems. Consequently, this configuration meets the fire safety requirements for education, healthcare, and multi-storey commercial applications under Part B of the Building Regulations.

Key Inclusions

REI60 fire-rated panels
FD60 fire doors & emergency lighting
Addressable fire alarm system
From £28,000 ex-works
Best for
Schools, classrooms, healthcare clinics, multi-storey offices, public sector buildings
Part L A-Rated

ISO Frame Part L A-Rated Specification

Our highest specification combines REI60 fire rating with enhanced thermal performance, triple glazing, MVHR ventilation, and air-source heat pump heating. In particular, this configuration achieves EPC A-rating and exceeds current Part L 2021 requirements for new non-domestic buildings.

Key Inclusions

Triple-glazed aluminium windows (U 0.7)
Air-source heat pump (SCOP 4.5)
MVHR mechanical ventilation
From £38,000 ex-works
Best for
Permanent offices, education buildings, public sector, net-zero programmes, long-term commercial use

Quick Specification Comparison

Feature Standard REI60 Part L A-Rated
Wall U-Value 0.25 W/m²K 0.18 W/m²K 0.16 W/m²K
Fire Rating EI 30 REI 60 REI 60
Windows PVC double Alu double Alu triple (U 0.7)
Heating Panel heaters Panel heaters ASHP (SCOP 4.5)
Ventilation Natural Mechanical extract MVHR
Fire Doors FD30 FD60 FD60
Starting From £18,000 £28,000 £38,000

All prices ex-works. Delivery, installation, and site preparation quoted separately. Prices subject to final specification and site survey.

Not sure which specification suits your project? Our technical team will advise on the most appropriate configuration based on your site, compliance requirements, and budget.

Discuss Your Specification
Technical Data

ISO Frame Specification
Dimensions, Performance & Compliance

The table below covers standard ISO frame modular building parameters across all three specification levels. However, bespoke dimensions and enhanced specifications are available on every project.

Parameter Standard Range Notes
Dimensions
External Width 2.44m (8ft) – 3.66m (12ft) Road-transportable without escort
External Length 6.06m (20ft) – 14.6m (48ft) Multi-unit linking for larger footprints
Internal Height 2.4m – 2.7m 2.7m standard on Part L A-Rated
Floor Area per Unit 15m² – 53m² Link units for 100m²+ configurations
Stacking Up to 3 floors ISO corner castings; each floor independent
Thermal Envelope
Wall U-Value 0.16 – 0.25 W/m²K KINGSPAN QuadCore panels; spec-dependent
Roof U-Value 0.11 – 0.18 W/m²K PVC PROTAN membrane; insulated deck
Floor U-Value 0.11 – 0.16 W/m²K PIR Thermano Deck insulation; SPC vinyl finish
Glazing Double or triple glazed (PVC or aluminium) U-value 0.7 – 1.4 W/m²K
Mechanical & Electrical
Electrical UK 230V; RCD consumer unit; IP65 LED lighting Emergency lighting on REI60 & Part L specs
Heating Panel heaters (Std/REI60); ASHP (Part L) SCOP 4.5 air-source heat pump on A-Rated
Ventilation Natural (Std); Mech extract (REI60); MVHR (Part L) Part F compliant across all specifications
Compliance & Certification
Building Regulations Part L, Part B, Part M, Part F Full documentation at handover
Structural Standard ISO 1090, ISO 3834, ISO 9001 Engineer sign-off included
Fire Rating EI 30 (Std); REI 60 (REI60 & Part L) FD30 / FD60 doors to match
Accessibility DDA compliant layouts; low threshold doors Part M compliant as standard
Programme & Warranty
Lead Time 4 – 12 weeks from order Subject to specification and programme
Installation Time 1 – 5 days on site 90% factory completed before dispatch
Structural Warranty 10 – 15 years Steel frame; extended terms for public sector
Panel & Roof Warranty 5 – 10 years KINGSPAN QuadCore manufacturer-backed
Windows & Doors Warranty 5 years Aluminium or PVC; all UK-standard hardware
Workmanship Warranty 12 – 24 months Internal fit-out and installation

Specification Notice

All specifications are indicative and subject to final design, site survey, and Building Regulations approval. Furthermore, bespoke dimensions, enhanced thermal performance, and sector-specific compliance requirements are available on request. Contact our technical team for project-specific data sheets.

Download the Full ISO Frame Technical Data Sheet

Includes full U-value tables, structural load data, fire test certificates, and compliance documentation for all three specification levels.

Request Data Sheet

Manufactured Under Certification

ISO 9001 ISO 1090 ISO 3834 ISO 14001 Constructionline Bronze SSIP Accredited Acclaim Certified
Our Process

From Enquiry to Handover
in 6 Structured Stages

Every ISO frame modular building project follows the same proven delivery programme. Consequently, clients receive a fully compliant, factory-finished building within 8–12 weeks of order confirmation — with full visibility at every stage.

Stage 1 Week 1

Enquiry & Technical Brief

Your project begins with a detailed technical brief. Our team reviews your site constraints, compliance requirements, programme, and budget to establish the most appropriate ISO frame specification from the outset.

Deliverables

Site feasibility assessment
Specification recommendation
Indicative budget & lead time
Stage 2 Weeks 1–2

Design & Quotation

Following the brief, our design team produces detailed floor plans, elevation drawings, and a full itemised quotation. In addition, all layouts are reviewed against Building Regulations Part L, Part B, Part M, and Part F before submission to the client.

Deliverables

Floor plans & elevations
Full itemised quotation
Compliance pre-check report
Stage 3 Weeks 2–3

Order Confirmation & Payment

Once the quotation is approved, a formal order is placed with a 40% deposit to release the manufacturing slot. Subsequently, the remaining 55% is invoiced prior to dispatch, with a 5% retention payable within 14 days of practical completion.

Deliverables

Signed order confirmation
40% deposit invoice
Manufacturing slot confirmed
Stage 4 Weeks 3–10

Factory Manufacture & QA

Manufacturing takes place entirely within our ISO 9001-certified factory. Each unit undergoes staged quality inspections covering structural welding (ISO 3834), panel installation, electrical first fix, internal fit-out, and final pre-dispatch sign-off before leaving the factory floor.

Deliverables

Staged QA inspection reports
Factory completion photographs
Pre-dispatch sign-off certificate
Stage 5 Weeks 10–11

Delivery & Site Installation

Units are transported on standard low-loaders and craned into position using HIAB or mobile crane. Moreover, our installation teams complete all on-site connections — electrical, mechanical, and structural — within 1–5 days, minimising disruption to your site operations throughout.

Deliverables

HIAB / crane lift plan
On-site installation & connections
Site safety method statement
Stage 6 Week 12

Handover, Certification & Aftercare

Practical completion is confirmed with a full handover pack including as-built drawings, compliance certificates, warranty documentation, and operating manuals. Additionally, our aftercare team remains available for the duration of the warranty period to support any post-handover queries or remedial works.

Deliverables

As-built drawings & O&M manuals
Compliance & warranty certificates
Aftercare contact & support pack

Typical Programme Summary

8–12
Weeks Total
1–5
Days On Site
90%
Factory Completed
6
Structured Stages
15yr
Structural Warranty

Ready to start your project? Our team will confirm your programme and manufacturing slot within 24 hours of your enquiry.

Start Your Project
Case Studies

ISO Frame Projects
Delivered Across the UK

The following projects demonstrate the breadth of ISO frame modular building applications across education, public sector, and commercial sectors. Each project was delivered within programme and to full Building Regulations compliance.

ISO frame modular classroom installed at a UK secondary school — REI60 fire-rated, Part L compliant
Education
REI60 Spec
📍 UK Secondary School · 📅 10 Weeks

REI60 Modular Classroom Block — 4 Units Linked

A secondary school required four additional classrooms ahead of a September term start. Consequently, four ISO frame units were linked to form a single 212m² classroom block, fully insulated to REI60 standard with FD60 fire doors, addressable fire alarm, and DDA-compliant access throughout.

Project Highlights

4 units linked; 212m² total floor area
REI60 panels; FD60 fire doors throughout
Part L, Part B, Part M compliant
Delivered in 10 weeks from order
3-day on-site installation

Client Outcome

"Classrooms were ready two weeks before term started. The build quality exceeded our expectations and the installation team were professional throughout."

ISO frame welfare unit with external staircase on a UK construction site — KINGSPAN insulated panels
Construction
Hire-to-Buy
📍 Birmingham, West Midlands · 📅 6 Weeks

2-Storey Welfare & Office Unit — City Centre Site

A civil engineering contractor required a two-storey welfare and office solution for a city centre infrastructure project with restricted access. As a result, two ISO frame units were stacked using ISO corner castings, with an external staircase and HIAB installation completed within a single working day.

Project Highlights

2-storey stack; ISO corner castings
HIAB installation; 1-day on site
Canteen, WC, drying room & offices
Hire-to-buy agreement; 24-month term
Fully relocated at project completion

Client Outcome

"The stacked unit solved our space problem on a very tight city centre plot. Hire-to-buy meant we kept cash in the business during the project."

Bespoke ISO frame modular office building manufactured in KC Modular Buildings UK factory — Part L A-rated
Commercial
Part L A-Rated
📍 East Midlands · 📅 12 Weeks

Part L A-Rated Modular Office — 6 Units Linked

A logistics company needed a permanent, energy-efficient headquarters to replace ageing Portakabin offices. Accordingly, six ISO frame units were linked to create a 318m² open-plan office with meeting rooms, kitchen, and accessible WC facilities — all achieving EPC A-rating under Part L 2021.

Project Highlights

6 units linked; 318m² open-plan layout
EPC A-rated; Part L 2021 compliant
Triple-glazed aluminium windows (U 0.7)
ASHP heating & MVHR ventilation
15-year structural warranty

Client Outcome

"Our energy bills dropped by over 60% compared to the old Portakabin offices. The building looks and feels permanent — visitors can’t tell it’s modular."

Aggregated Project Results

100%
On Programme
730m²
Total Floor Area
12
ISO Frame Units
3
Sectors Served
60%
Energy Saving

Trusted by Clients Across

Education Construction Commercial Healthcare Residential Sports & Leisure

Have a similar project in mind? Our technical team will provide a specification recommendation and programme estimate within 24 hours.

FAQ

Frequently Asked Questions
About ISO Frame Modular Buildings

Below are the most common questions we receive from clients considering ISO frame modular buildings. If your question is not answered here, our technical team is available to help.

An ISO frame modular building is a steel-framed structure built around standardised ISO corner castings — the same connection system used on shipping containers. This allows units to be stacked up to 3 floors, transported on standard low-loaders, and lifted by HIAB or mobile crane.

How ISO Frame Differs from Shipping Containers

Unlike converted shipping containers, ISO frame buildings are purpose-built with KINGSPAN insulated panels, full electrical and mechanical systems, and factory-finished interiors to Building Regulations standard. Consequently, they deliver superior thermal performance, acoustic insulation, and a professional interior finish suitable for offices, classrooms, and healthcare facilities.

Typical programmes run 8–12 weeks from order confirmation to practical completion. Manufacturing takes 4–10 weeks depending on specification and complexity. On-site installation takes just 1–5 days because 90% of the build is completed under factory conditions before dispatch.

Why Factory Build Eliminates Delays

Lead times are confirmed at order stage and are not affected by weather delays. Furthermore, all structural, electrical, and internal fit-out work is completed in a controlled factory environment under ISO 9001 quality management, ensuring consistent quality and programme certainty on every project.

KC Modular Buildings offers three specification levels: Standard (KINGSPAN insulated panels, PVC double glazing, panel heaters, from £18,000), REI60 Fire-Rated (60-minute fire-rated panels, FD60 doors, addressable fire alarm, from £28,000), and Part L A-Rated (triple-glazed aluminium windows, air-source heat pump, MVHR ventilation, EPC A-rating, from £38,000).

Choosing the Right Specification

All specifications are manufactured under ISO 9001, ISO 1090, and ISO 3834 certification. In addition, our technical team will recommend the most appropriate specification based on your site, sector, compliance obligations, and budget during the initial consultation.

Yes. ISO frame units can be stacked up to 3 floors using ISO corner castings, with each floor structurally independent. Units can also be linked side-by-side to create larger open-plan floor areas — for example, six linked units can deliver over 300m² of usable space.

Multi-Storey & Linked Configurations

External staircases, walkways, and lift shafts can be integrated into multi-storey configurations. Furthermore, linked units share a continuous roofline and internal corridor, creating a seamless building envelope that is indistinguishable from a traditionally constructed structure.

Yes. All ISO frame modular buildings from KC Modular Buildings are designed and manufactured to comply with Part L (energy efficiency), Part B (fire safety), Part M (accessibility), and Part F (ventilation) of the Building Regulations.

Compliance Documentation at Handover

REI60 and Part L A-Rated specifications include enhanced fire rating, FD60 doors, and addressable fire detection systems. Full compliance documentation — including as-built drawings, engineer sign-off, and Building Regulations certificates — is provided at handover on every project.

Yes. Every ISO frame unit is fully relocatable. Units can be disconnected, lifted by HIAB or crane, transported on a standard low-loader, and reinstalled at a new site without any loss of structural integrity or certification validity.

Retained Value & Warranty

All certifications and warranties remain valid regardless of how many times the building is relocated. As a result, ISO frame buildings retain their full residual value and compliance status throughout their service life — making them ideal for hire fleet, phased programmes, and temporary site requirements.

KC Modular Buildings provides a 10–15 year structural warranty on the steel frame, 5–10 years on KINGSPAN panels and roof, 5 years on windows and doors, and 12–24 months on internal workmanship and installation.

Extended Terms for Public Sector

Extended warranty terms are available for public sector and education contracts. Moreover, all warranties are backed by manufacturer certifications and independent QA inspection records completed at each stage of the factory build programme.

ISO frame modular buildings are used across education (classrooms, SEN units, sixth form centres), construction (site offices, welfare units), commercial (offices, showrooms, retail), healthcare (clinics, consulting rooms), residential (modular homes, annexes), and sports and leisure (pavilions, clubhouses, changing rooms).

UK-Wide Sector Coverage

KC Modular Buildings has delivered ISO frame projects across all of these sectors throughout England, Wales, and Scotland. In particular, education and public sector clients benefit from our framework buying options, extended warranties, and full compliance documentation packages.

Standard payment terms are 40% deposit at order confirmation, 55% prior to dispatch, and 5% retention within 14 days of practical completion. Flexible procurement options include hire, hire-to-buy, and lease/asset finance agreements through approved partners (typically 3–7 year terms).

Framework & Public Sector Procurement

Framework and call-off agreements are available for repeat clients and public sector buyers. Additionally, milestone payment schedules can be structured for larger multi-unit programmes to align with your project cash flow and procurement requirements.

ISO frame buildings from KC Modular Buildings achieve wall U-values of 0.16–0.25 W/m²K, roof U-values of 0.11–0.18 W/m²K, and floor U-values of 0.11–0.16 W/m²K depending on specification.

Part L A-Rated Performance

The Part L A-Rated specification includes triple-glazed aluminium windows (U-value 0.7 W/m²K), air-source heat pump (SCOP 4.5), and MVHR ventilation, achieving EPC A-rating and exceeding Part L 2021 requirements. Consequently, clients typically report energy cost reductions of 40–60% compared to older portable cabin or Portakabin-style buildings.

Still Have a Question?

Our technical team responds to all enquiries within 24 hours. Contact us directly by phone or email, or submit a project brief using the form below.

ISO 9001 ISO 1090 ISO 3834 ISO 14001 Constructionline Bronze SSIP Accredited Acclaim Certified

Ready to Specify Your
ISO Frame Modular Building?

Our technical team will review your site, compliance requirements, and programme — then recommend the most appropriate specification and provide a full itemised quotation within 24 hours.

8–12 Week Programme
90% Factory Completed
Full Compliance Docs
Buy, Hire or Hire-to-Buy
UK-Wide Delivery

Phone

07443 564 451

Mon–Fri, 8am–6pm

Email

[email protected]

Response within 24 hours

Coverage

UK-Wide

England, Wales & Scotland

Lead Time

8–12 Weeks

From order to handover

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