🏗️ Modular Building System

What is an ISO Frame Modular Building?

The ISO Frame series is a flexible modular system designed for rapid deployment, repeatable installation, and long lifespan. Factory-built with precision-engineered steel frames, these units are ideal for offices, welfare facilities, classrooms, storage, security cabins, and multi-storey configurations up to three levels.

📖 ISO Frame Modular Building Definition

An ISO frame modular building is a prefabricated steel-framed structure manufactured off-site to ISO quality standards. Built using cold-bent steel profiles with bolted construction (flat-pack capability), these units feature mineral wool insulated walls, floors, and roofs. They are CE marked to EN 1090-1, welded per EN ISO 3834-2, and blast-cleaned to Sa 2.5. ISO frame buildings can be stacked up to three storeys, transported by standard HGV, and installed in days rather than months.

🏢

Standard ISO Frame

General Purpose

Our core modular unit for offices, welfare, storage, and commercial use. Robust steel construction with 80mm mineral wool insulation.

✓80mm mineral wool walls
✓100mm insulated roof & floor
✓U-value 1.1 W/m²K windows
✓2000 kg/m² floor load
✓Stackable up to 3 floors
✓Full UK electrical system

🔥

REI60 Fire-Rated

Enhanced Fire Protection

Designed for schools, healthcare, public buildings, server rooms, and accommodation requiring 60-minute fire resistance.

✓REI 60 fire rating
✓120mm Rockwool insulation
✓Fire-resistant plasterboards
✓Fire-rated frame construction
✓Stackable up to 2 floors
✓Ideal for grouped buildings

🌱

Part L A-Rated

Maximum Energy Efficiency

Top-tier energy performance compliant with England Building Regulations Part L 2021 for non-domestic buildings.

✓A-Rated energy performance
✓240mm mineral wool walls
✓Dual 120mm PIR floor insulation
✓U-value 0.5 W/m²K glazing
✓4.5 SCOP air-air heat pump
✓Lowest running costs

⚡

Rapid Installation

Factory-built and delivered ready to use. Install in days, not months.

📦

Flat-Pack Option

Bolted construction allows flat-pack transport for remote or restricted sites.

🏗️

Stackable 3 Floors

Maximise site footprint with multi-storey configurations up to three levels.

🔄

Fully Relocatable

Move, reconfigure, or redeploy units as your business needs change.

🛡️

ISO Certified

Manufactured under ISO 9001, 1090, 3834, 14001, and EN 1090-1 CE marking.

💰

Buy or Hire

Flexible ownership options to suit project budgets and timelines.

🚚

4–12 Week Delivery

Fast turnaround from order to installation, UK-wide delivery included.

🔧

Minimal Maintenance

Factory finishes, coated steel, and durable interiors reduce upkeep costs.

📋 Technical Data

ISO Frame Technical Specifications

Detailed construction specifications for all three ISO frame tiers. Select a specification level to view full technical breakdown.

Component	Specification
🏗️ Structure
Frame Construction	Cold-bent steel profiles, bolted construction (flat-pack capable)
Welding Standard	EN ISO 3834-2 certified
CE Marking	EN 1090-1 compliant
Surface Preparation	Abrasive blast-cleaned to Sa 2.5 (EN ISO 8501-1)
Stackability	Up to 3 floors
🏠 Roof Construction
External Layer	0.5mm galvanized steel sheet
Substrate	10mm chipboard
Insulation	100mm mineral wool
Vapour Barrier	Polyethylene membrane
Internal Finish	8mm laminated board (white)
Drainage	Integrated via frame and downpipes
Snow Load Capacity	1.6 kN/m²
🧱 Wall Construction
External Cladding	0.5mm steel sheet, trapezoidal linear design
Insulation	80mm mineral wool core
Internal Finish	0.5mm smooth sheet, RAL 9010 (Pure White)
🪵 Floor Construction
Deck	22mm P5 chipboard
Insulation	100mm mineral wool
Underside	0.5mm galvanized steel
Load Capacity	2000 kg/m²
Floor Finish	2mm commercial-grade PVC, grey, sealed joints
🚪 Windows & Doors
Windows	PVC frame, RAL 7016 exterior / white interior, U-value 1.1 W/m²K
DDA Glazed Door	1150×2100mm, RAL 7016/white, insulated glazing, 3-key cylinder lock	1150×2100mm, fire-rated glazing, enhanced seals, automatic closer	1150×2100mm, U-value 0.5 W/m²K, thermal break frame
Steel Single Door	900×2000mm, thermally insulated, secure locking system	900×2000mm, fire-rated FD60, intumescent seals	900×2000mm, thermally insulated, enhanced weatherseals
Electrical System	Full 230V UK standard, metal consumer unit, RCD protection	Full 230V UK standard, fire-rated cable containment	Full 230V UK standard, energy monitoring ready
Lighting	IP65 LED fittings (2×18W), UK sockets and switches	IP65 LED fittings, emergency lighting, illuminated exit signs	IP65 LED fittings, daylight sensors, dimming controls
Heating	Convector heaters (standard)	Convector heaters (standard)	4.5 SCOP air-air heat pump ⚡ A-Rated efficiency
Snow Load	1.6 kN/m²	1.6 kN/m²	1.6 kN/m²
Stackability	Up to 3 floors	Up to 2 floors	Up to 3 floors
Fire Rating	Standard (mineral wool core)	REI 60: Load-bearing 60 min, Integrity 60 min, Insulation 60 min 🔥 60-minute protection	Standard (mineral wool core)
Energy Rating	Standard compliance	Standard compliance	Part L 2021 compliant ⚡ A-Rated performance
Ideal Applications	Offices, welfare units, storage, site cabins, security	Schools, healthcare, public buildings, server rooms, accommodation	Long-term offices, classrooms, NHS sites, low-carbon projects

🎨 Available RAL Colour Options

Frame and wall panel finishes available in standard RAL colours. Custom colours available on request.

RAL 3000 Flame Red

RAL 5010 Gentian Blue

RAL 7016 Anthracite Grey

RAL 7035 Light Grey

RAL 9002 Grey White

RAL 9010 Pure White

🏆 Manufacturing & Quality Certifications

All ISO frame units manufactured under strict certified quality systems for guaranteed consistency, safety, and traceability.

✓

ISO 9001 Quality Management

✓

ISO 1090 Structural Steel CE

✓

ISO 3834 Welding Quality

✓

ISO 14001 Environmental

✓

ISO 27001 Information Security

✓

ISO 22301 Business Continuity

✓

EN ISO 8501 Surface Preparation

✓

EN 1090-1 CE Marking

📄 Request Full Spec Sheet → ⬇️ Download Brochure

✨ Key Advantages

Why Choose ISO Frame Modular Buildings?

Engineered for speed, durability, and flexibility. ISO frame buildings deliver measurable benefits over traditional construction methods.

⚡

Rapid Installation & Redeployment

100% modular, transportable, and stackable. Factory-built units arrive ready to install in days, not months.

✓4–12 week delivery from order
✓Minimal site disruption
✓Relocate units as needs change

💰

Low Running Costs

High-insulation build-ups and energy-efficient systems dramatically reduce heating bills and operational expenses.

✓Part L A-Rated option available
✓4.5 SCOP heat pump efficiency
✓Up to 60% lower energy costs

📈

Flexible to Grow With Your Needs

Units can be added, extended, reconfigured, or relocated easily as your business or project requirements evolve.

✓Stackable up to 3 storeys
✓Link multiple units together
✓Flat-pack for restricted sites

🏗️

High Structural Integrity

Precision-engineered steel frames ensure long lifespan, stability, and safety for temporary or permanent installations.

✓CE marked EN 1090-1
✓2000 kg/m² floor load capacity
✓1.6 kN/m² snow load rating

🔥

Fire & Energy Compliance Options

Choose Standard, REI60 fire-rated, or Part L A-Rated specification depending on your project requirements.

✓REI 60 fire protection
✓Part L 2021 compliant
✓Suitable for schools & healthcare

🔧

Minimal Maintenance

Factory finishes, coated steel, and durable interiors reduce upkeep costs and extend building lifespan.

✓UV-resistant RAL coatings
✓Wipe-clean internal surfaces
✓Sealed PVC flooring

4–12

Week Delivery

Storey Stackable

Min Fire Rating

2000

kg/m² Floor Load

ISO Certifications

Get Your Free Quote →

Flagship modular office building with steel frame system demonstrating permanent planning-compliant construction

Planning Guidance • Schools & Public Sector

Modular Buildings Are Often Assumed to Be Temporary — But Planning May Treat Them as Permanent Development

In practice, "temporary vs permanent" is usually assessed through intended use and site integration — not how the building is manufactured.

Planning outcomes depend on site conditions and local authority interpretation, and no single building approach guarantees approval.

💬 Request Guidance 📞 07443 564 451 📄 Modular Schools Guide

Example image used to illustrate the topic. Final planning assessment depends on site context and supporting documentation.

Key Takeaway

"Temporary vs Permanent" Is Usually Judged by Use and Site Integration — Not Construction Method

Modular buildings are often assumed to be temporary by default. In planning, that assumption can be risky. Many modular projects are assessed as permanent development depending on intended duration, connections to services, fixing methods, and how the proposal sits within the site.

✓
Intended use & duration is often the starting point for how a proposal is assessed.
✓
Site integration (access routes, layout, neighbours, outdoor areas) typically matters more than manufacturing method.
✓
Clarity in supporting information helps reduce follow-up questions and improves decision confidence.

Planning outcomes depend on site conditions and local authority interpretation, and no single building approach guarantees approval.

🏫

Modular Schools Guidance

Education-focused context for modular school projects

🏫

Modular Schools Guidance

Education-focused context for modular school projects

📩

Contact KC for Guidance

Share your site constraints and we'll help you frame the right information

🌐

Planning Portal (Official Guidance)

Reference information for planning applications (external)

🏢 Industries We Serve

ISO Frame Buildings for Every Sector

From construction sites to classrooms, our modular buildings deliver fast, compliant, and cost-effective space solutions across the UK.

🏫

Education

Modular classrooms, dining halls, and admin blocks for schools, colleges, and universities. Part L compliant with rapid installation during term breaks.

Schools Colleges Universities

View education solutions →

🏗️

Construction

Site offices, welfare units, drying rooms, and canteens for contractors. Stackable up to 3 storeys with hire or purchase options.

Site Offices Welfare Units Drying Rooms

View construction solutions →

🏢

Commercial

Modular offices, showrooms, and retail units for businesses. Energy-efficient with Part L A-Rated options for long-term operational savings.

Offices Showrooms Retail

View commercial solutions →

🏛️

Public Sector

Council offices, community centres, and government facilities. DDA compliant with REI60 fire-rated options for public safety requirements.

Councils Government Community

Discuss your project →

🏥

Healthcare

Medical clinics, testing centres, and NHS facilities. Hygienic finishes, acoustic insulation, and full accessibility compliance.

Clinics NHS Testing Centres

View healthcare solutions →

🏨

Hospitality & Leisure

Modular hotels, restaurants, sports pavilions, and event spaces. Premium finishes with rapid deployment for seasonal demand.

Hotels Restaurants Sports Clubs

View hospitality solutions →

Discuss Your Sector Requirements →

❓ Common Questions

ISO Frame Modular Buildings FAQ

Answers to the most common questions about our ISO frame modular building systems, specifications, and delivery.

How long does delivery take for ISO frame buildings?

Standard ISO frame units are typically delivered within 4–12 weeks from order confirmation, depending on specification and customisation requirements.

Factors affecting delivery time include:

Standard units: 4–6 weeks
REI60 fire-rated: 6–8 weeks
Part L A-Rated: 8–10 weeks
Bespoke configurations: 10–12 weeks

We maintain stock of popular sizes for faster turnaround on urgent projects.

Do ISO frame buildings require planning permission?

Planning requirements depend on intended use, duration, and site context rather than construction method. Modular buildings are often assessed as permanent development.

Key considerations include:

Temporary use: May qualify for permitted development (typically under 28 days)
Permanent installation: Usually requires full planning application
Education/NHS: May benefit from fast-track or delegated approval

We recommend consulting your local planning authority early. Our team can provide supporting documentation and technical specifications for your application.

What fire rating options are available?

We offer three specification tiers with different fire performance levels:

Standard: Mineral wool insulation provides inherent fire resistance suitable for most commercial applications
REI60 Fire-Rated: 60-minute load-bearing, integrity, and insulation rating with Rockwool insulation, fire-rated doors (FD60), and intumescent seals
Part L A-Rated: Standard fire resistance with enhanced thermal performance

REI60 specification is recommended for schools, healthcare, public buildings, and accommodation where enhanced fire protection is required.

Can ISO frame buildings be stacked or linked together?

Yes. ISO frame buildings are designed for modular expansion:

Vertical stacking: Up to 3 storeys (Standard/Part L) or 2 storeys (REI60)
Horizontal linking: Multiple units can be joined side-by-side or end-to-end
Flat-pack option: Available for restricted access sites where craning isn't possible

Internal connecting doors and corridors can be factory-fitted or added on-site. This flexibility allows you to start small and expand as your needs grow.

What warranty do you offer on ISO frame buildings?

All KC Modular ISO frame buildings come with comprehensive warranty coverage:

15-year structural warranty: Covers the steel frame, welded joints, and load-bearing components
24-month defects warranty: Covers finishes, fittings, doors, windows, and electrical/plumbing systems
Manufacturer warranties: Individual component warranties (e.g., heat pumps, sanitary fittings) as per manufacturer terms

Warranty is subject to proper installation, use, and maintenance in accordance with our guidelines.

Are ISO frame buildings energy efficient?

Yes. All specifications include high-performance insulation, but our Part L A-Rated option delivers maximum energy efficiency:

Walls: 240mm mineral wool (U-value 0.16 W/m²K)
Roof: 125mm PIR + 60mm mineral wool (U-value 0.11 W/m²K)
Floor: Dual 120mm PIR (U-value 0.11 W/m²K)
Windows: Triple-glazed (U-value 0.5 W/m²K)
Heating: 4.5 SCOP air-air heat pump

Part L A-Rated buildings can reduce energy costs by up to 60% compared to standard construction, making them ideal for long-term installations.

What certifications do your ISO frame buildings have?

All ISO frame buildings are manufactured under strict certified quality systems:

ISO 9001: Quality Management System
ISO 1090 / EN 1090-1: Structural Steel CE Marking
ISO 3834: Welding Quality Assurance
ISO 14001: Environmental Management
ISO 27001: Information Security
ISO 22301: Business Continuity
EN ISO 8501: Surface Preparation Standard

We also hold Constructionline Bronze, SSIP, and Acclaim accreditations for health and safety compliance.

Can I hire ISO frame buildings instead of buying?

Yes. We offer flexible hire and purchase options to suit different project requirements:

Short-term hire: Ideal for construction sites, events, or temporary capacity needs
Long-term hire: Cost-effective for projects with uncertain duration or phased requirements
Purchase: Best value for permanent installations with 15-year structural warranty
Hire-to-buy: Start with hire and convert to purchase, with rental payments offset against the final price

Asset finance is also available for purchases, with 40% deposit, 55% before delivery, and 5% within 14 days of installation.

Still have questions? Our team is ready to help with technical specifications, pricing, and project planning.

💬 Ask a Question 📞 07443 564 451

🚀 Get Started Today

Request Your Free ISO Frame Quote

Tell us about your project and we'll provide a detailed quotation within 24 hours. No obligation, no pressure — just expert guidance on the right solution for your needs.

✓ Free site survey

✓ 24-hour quote turnaround

✓ No obligation

✓ Finance options available

📞

Call Us 07443 564 451

📧

Email Us [email protected]

🕐

Hours Mon–Fri: 8am–6pm

Get Your Free Quote

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⭐ Customer Reviews

Trusted by Businesses Across the UK

See what our customers say about their ISO frame modular buildings — from schools to construction sites.

4.8/5

★★★★★

Average Rating

47+

Verified Reviews

98%

Would Recommend

15+

Years Experience

★★★★★

"The modular classroom block was delivered and installed during the summer holidays — ready for September term. Build quality is excellent, and the Part L compliance made planning straightforward. Highly recommend for any school expansion project."

James Harrison Estates Manager 🏫 Education

★★★★★

"We've hired welfare units from KC for three major projects now. The 2-storey stacked configuration saved valuable site space, and the quality is far better than typical hire units. The team were responsive and delivery was on time."

Mark Thompson Site Manager, Balfour Construction 🏗️ Construction

★★★★★

"The REI60 fire-rated specification was essential for our NHS clinic. KC delivered a fully compliant building with hygienic finishes and excellent acoustic insulation. Patients and staff have commented on how professional it looks."

Dr. Sarah Patel Practice Manager 🏥 Healthcare

★★★★★

"Our new sales office was installed in just 6 weeks from order. The Part L A-Rated spec means our energy bills are minimal, and the modern design impresses customers. Best investment we've made for the dealership."

Richard Brooks Director, Brooks Motor Group 🏢 Commercial

★★★★☆

"KC provided utility blocks for our traveller site project under tight timelines. The DDA compliance and fire safety features met all our requirements. Communication was excellent throughout, though we'd have liked slightly faster initial response."

Laura Williams Project Officer, Surrey County Council 🏛️ Public Sector

★★★★★

"The modular kitchen unit transformed our outdoor event space. Factory-fitted extraction, plumbing, and electrics meant we were operational within days of delivery. Build quality exceeded our expectations for a 'portable' building."

Alex Carter Owner, The Lakeside Venue 🏨 Hospitality

Ready to join our satisfied customers? Get your free quote today.

Request Free Quote →

ISO Frame Modular Buildings

📖 ISO Frame Modular Building Definition

Standard ISO Frame

REI60 Fire-Rated

Part L A-Rated

Rapid Installation

Flat-Pack Option

Stackable 3 Floors

Fully Relocatable

ISO Certified

Buy or Hire

4–12 Week Delivery

Minimal Maintenance

Office Units

Sanitary Units

Bespoke Units

Modular Schools

🎨 Available RAL Colour Options

🏆 Manufacturing & Quality Certifications

Rapid Installation & Redeployment

Low Running Costs

Flexible to Grow With Your Needs

High Structural Integrity

Fire & Energy Compliance Options

Minimal Maintenance

Modular Buildings Are Often Assumed to Be Temporary — But Planning May Treat Them as Permanent Development

"Temporary vs Permanent" Is Usually Judged by Use and Site Integration — Not Construction Method

Education

Construction

Commercial

Public Sector

Healthcare

Hospitality & Leisure

How long does delivery take for ISO frame buildings?

Do ISO frame buildings require planning permission?

What fire rating options are available?

Can ISO frame buildings be stacked or linked together?

What warranty do you offer on ISO frame buildings?

Are ISO frame buildings energy efficient?

What certifications do your ISO frame buildings have?

Can I hire ISO frame buildings instead of buying?

Request Your Free ISO Frame Quote

Get Your Free Quote

Modular Classrooms

Welfare Units

Modular Offices

Bespoke Buildings

Medical Clinics

Luxury Lodges