Specifying container homes correctly comes down to three questions that have to be answered together: how the modules carry load when stacked, how the envelope manages moisture and heat, and what documentation the local authority will accept before it issues a permit. Because the structural, thermal and regulatory decisions interact, a change to one usually forces a change to the others. This guide sets out the design rules CDPH applies to its module system, the insulation build-up behind them, and the permit evidence a project buyer should expect to assemble. It is written for procurement teams and project engineers comparing container homes against site-built alternatives, and it assumes the reader will be reviewing drawings and certificates rather than show-home photography.
How container homes are engineered as a structural system
The CDPH system is not a converted shipping container. It is a modular building system in which factory-prefabricated steel modules are bolted together on site, then can be unbolted, relocated and reused on another project. Each module is a complete three-dimensional unit with its own frame, floor, roof, walls, services and finishes, so site work centres on foundations, connection, service tie-ins and finishing.
The frame is galvanised cold-formed steel at 3.0 mm thickness, grade SGH340, prefabricated in the factory. That gauge and coating specification matters for two reasons. First, the frame uses cold-formed sections at 3 mm and the modules connect with bolts; buildings are configured as single, double, triple or more storeys. Second, galvanising protects the frame during transport and during the service life of a relocatable building, where the structure may be exposed to site conditions repeatedly between deployments.
Two module footprints are produced:
| Parameter | Module type A | Module type B |
|---|---|---|
| External dimensions | 6055 × 2990 × 2896 mm | 6055 × 2435 × 2896 mm |
| Internal dimensions | 5845 × 2780 × 2500 mm | 5845 × 2225 × 2520 mm |
| Frame | Galvanised cold-formed steel, t=3.0 mm, SGH340 | Galvanised cold-formed steel, t=3.0 mm, SGH340 |
| Roof live load | 1.0 / 0.5 kN/m² | 1.0 / 0.5 kN/m² |
| Floor live load | 2.0 kN/m² | 2.0 kN/m² |
| Wind load | 0.6 / 0.5 kN/m² | 0.6 / 0.5 kN/m² |
The system is recorded in two widths, and buildings can be single, double, triple or more storeys. Which width serves which function in a given layout is a design decision taken per project. Layouts are configured as I, U, L or courtyard plans by combining modules and closing the junctions between them. Stacking is a matter of aligning vertical load paths through the corner and edge posts, so the designer's first task is to fix a grid before choosing room sizes — not the reverse.
Services are integrated into the modules rather than added afterwards. Electrical circuits are pre-fitted in the roof, water supply runs along the walls, and drainage is wall-side. With this routing, service riser positions have to be agreed at layout stage. Moving a wet core after the factory drawing is released is a rework cost, not a drawing change.
Two format variants are built on the same module logic. Flat pack modules are the 6055 mm standard box packed flat for transport and assembled on site; detachable modules are bolted and demountable so the building can be taken apart and reused. For projects where the building will be relocated — engineering camps, construction camps, emergency facilities — the detachable format is usually the correct starting point, because the connection detail is designed for reversal. Buyers who want a finished, transportable building rather than a kit should review the container houses range, and those comparing format variants before tendering can work through the prefab container houses overview.
Insulation and envelope design rules
Thermal performance in this system is determined by the build-up, not by a single product. Roof and floor both use 100 mm glass wool insulation. Walls use 75 mm colour-steel sandwich panels and seamless S-type rock wool composite panels. Two wall types are listed in the specification: 75 mm colour-steel sandwich panels and seamless S-type rock wool composite panels. Which panel a project uses is confirmed at engineering review.
- Roof and floor: 100 mm glass wool, installed in the factory.
- Walls: 75 mm colour-steel sandwich panels or seamless S-type rock wool composite panels, as specified for the project.
- Floor finish: 1.5 / 1.6 mm rubber-plastic flooring, appropriate for repeated cleaning in camp and commercial use.
- Openings: steel doors; integrated PVC sliding windows with security bars and fly screens.
- Services: electrical circuits pre-fitted in the roof; water supply along the walls; wall-side drainage.
Three practical rules follow from this build-up. First, thermal bridges at module-to-module junctions must be detailed deliberately — where two conditioned modules meet, the joint is a line of reduced resistance, and the envelope strategy has to treat it as such rather than assuming the panel performance applies uninterrupted. Second, cold-climate projects need the wall and roof specification reviewed against the actual design temperature, because the standard build-up is a baseline, not a universal answer; CDPH has delivered a copper mine camp for conditions down to −55 °C, and the envelope and services specification for that project was developed around the design condition. Third, ventilation and internal moisture control belong in the design from the start, particularly where occupancy is dense and the building is sealed against a harsh exterior.
Fire performance should be confirmed by test evidence rather than inferred. CDPH holds Intertek fire-resistance certification, and a living camp supplied for a solar power station in Saudi Arabia had its fire performance verified by Intertek testing. For projects where the authority or insurer requires fire evidence, buyers should confirm which certification scope applies to their project at engineering review.
Layout, stacking and transport constraints
Design rules for container homes are partly rules about movement. Every module has to travel from the factory to site, be lifted into position, and — in the detachable format — potentially travel again later. The module dimensions are therefore a transport envelope as much as a room size, and the layout has to be developed with the route and the lifting plan in view.
Stacking is governed by the load figures in the table above: 2.0 kN/m² floor live load, roof live load of 1.0 / 0.5 kN/m², and wind load of 0.6 / 0.5 kN/m². These are design values for the standard configuration, so any project that adds heavy equipment, plant rooms on upper levels, or significant snow accumulation needs those loads reviewed explicitly. Do not assume the published figures cover a plant deck.
Layout choice should follow function. I and L plans suit linear camp accommodation and site offices; U and courtyard plans suit education facilities, clinics and commercial buildings where a protected external space adds operational value. Single-storey configuration simplifies foundation and access; double and triple storeys release ground area but concentrate load paths and require the vertical alignment described earlier. For projects that combine accommodation, welfare and administrative functions on one site, the modular approach used across the container houses portfolio allows the mix to be resolved module by module rather than as one monolithic block.
Foundations, tie-downs and interface details are project-specific and are settled during engineering review, not from this page. The governing principle is that the foundation design must accept the bolted module grid and the wind uplift case for the site.
Permits: what the authority will ask for
Permitting rules for container homes vary by country, and often by municipality within a country. This page does not attempt to summarise them, because a summary would be wrong somewhere. What can be stated with confidence is the category of evidence that approval processes typically require, and what to request from a supplier.
- Structural documentation: frame specification, design loads, stacking arrangement and connection details — the items an approval process will expect to see at engineering review.
- Fire evidence: Intertek fire-resistance certification is held at category level; certificates available upon request.
- Product conformity: CE marking for modular container houses, prefab houses and light steel villas; Intertek ICC-ES / WH building-material compliance for the US market; NATA materials certification for Australia.
- Management and factory systems: ISO 14001 and ISO 45001; CCS factory approval; National High-Tech Enterprise status.
- Environmental documentation: product carbon footprint certification.
- Welding competence: 14 key welders qualified to AWS, CWB and CE standards.
Certificates available upon request. Buyers should identify at tender stage which certificates the local authority will accept and in what form — a certificate issued for one market may support a submission in another without being automatically accepted. Early confirmation avoids redesign after approval.
Two further permit points are worth raising with the authority before drawings are finalised. First, whether the building is classified as temporary or permanent affects foundation, egress and fire requirements, and the relocatable nature of the system does not by itself determine that classification. Second, site-specific conditions — seismic, wind, snow — may require design values beyond the standard figures, and the authority will normally want to see that the design case has been addressed.
Specifying the system and getting an engineering response
CDPH is a project-based manufacturer, so there is no standard minimum order quantity. Every project is quoted individually after engineering review, and the engineering team replies within one business day with a concept proposal and a budget range. That response is the right moment to test the design rules in this article against a real brief: module count, stacking, layout, envelope specification and the permit evidence required in the destination market.
The manufacturing base behind the response is three production bases in Hebei, Xinjiang and Sichuan, with the Hebei base 48 km from Tianjin Port. The company operates 13 subsidiaries and offices with more than 100 engineers and a team of over 500 people, and reports over 5,000 projects implemented in more than 100 countries, with export markets including Eastern Europe, North America, Southeast Asia and Africa. Overseas projects are run through CDPH (HAINAN) COMPANY LIMITED, the wholly-owned subsidiary of the Beijing corporation. Regional reference experience includes a port expansion camp in Cote d'Ivoire, a construction camp for a methanol plant, a camp for a cross-sea bridge project in Croatia, a natural gas project camp in Nigeria, a copper mine camp built for −55 °C conditions, and a living camp for a solar power station in Saudi Arabia with fire performance verified by Intertek testing.
To start an engineering review, send the site location, intended use, occupancy, number of storeys, required layout and the permit evidence your authority will expect. The team can be reached on Tel +86-10 69597331, phone/WhatsApp +86-180 01125803, WhatsApp +86-150 1044 5216 or [email protected], or through the contact page. The corporate office is at No. 8 Art Museum East Street, Xiaobao Art Park, Songzhuang Town, Beijing, China. Where a project needs a finished, transportable building rather than a flat-packed kit, review the prefab container houses options before the review call so that format, layout and envelope can be discussed together.