Specifying a prefabricated building for a project starts with understanding what “prefab homes” actually covers. The term is used loosely across the industry, but in practice it describes several distinct structural systems — light steel frame houses, wide-span prefabricated buildings and volumetric modular units — each with its own span limits, load capacities, transport profile and erection method. This guide sets out the main types, their advantages and constraints, and how project timelines typically run, written for project buyers, procurement teams and specifiers who need to compare systems on technical grounds. CDPH, the brand of Beijing Chengdong International Modular Housing Corporation, manufactures all three families from three production bases in China; this page explains how they differ so you can scope the right system before requesting a quotation.
What counts as a prefab home in a project context
For procurement purposes, a prefab home is any building whose primary structure and enclosure are manufactured in a factory and assembled on site. The degree of prefabrication varies considerably between systems, and this is the single most important variable when comparing offers. Two suppliers may both quote a “prefab home” while delivering fundamentally different products — one a panelised steel frame erected bolt by bolt, the other a volumetric module arriving with electrical circuits already fitted.
CDPH classifies its output into three systems:
- Light steel prefab houses (ZA Series) — highly prefabricated panelised buildings with a hot-galvanised cold-formed steel structure, suited to accommodation, offices and storage.
- Wide-span prefab houses (ZM Series) — larger clear-span structures for warehouses, workshops and storage buildings.
- Modular houses — factory-finished volumetric modules, bolted together on site, relocatable and reusable.
Each system is quoted per project; there is no standard minimum order quantity. Every enquiry goes through an engineering review, and the engineering team replies within one business day with a concept proposal and a budget range. Buyers who want to see the wider product range can review the main CDPH homepage or the dedicated prefabricated houses range before narrowing down the system.
Types of prefab homes and what each one is for
ZA Series light steel prefab houses
The ZA Series is a highly prefabricated, panelised design with a flexible internal layout and fast installation. The structure is hot-galvanised cold-formed steel, T=2–3 mm; external wall panels are corrosion-resistant and well insulated. Interior fit-out options cover bathrooms, kitchens, storage rooms, bedrooms, living rooms and open-plan offices — so a single system can serve as a site office, a living block or a combined facility.
The accommodation/office configuration supports spans up to 12 m and eaves heights up to 3.5 m; the storage type offers eaves heights up to 4.5 m. Both are customisable. Column spacing is 3.45 m. The double-pitch roof has a 1:5 slope. Erection is straightforward: a crew of four workers erects about 40 m² of structure per day, and about 200 m² of structure ships in one 40 ft container.
ZM Series wide-span prefab houses
Where the requirement is clear floor area rather than room subdivision, the ZM Series provides spans of 12, 15 or 18 m with an eaves height of 6 m and column spacing of 4 m or 6 m. Columns are M300 steel at T=3.0 mm, hot-galvanised; purlins are C170 at T=2.3 mm, also hot-galvanised. Typical uses are warehouses, workshops and storage buildings. Erection follows a different rhythm from the ZA Series: ten workers erect about 1,000 m² of structure in five days, and about 170 m² of structure ships in one 40 ft container.
Modular houses
Modular construction is the highest level of prefabrication: standard modules are manufactured in the factory, complete with fit-out, then bolted together on site. Modules are relocatable and reusable, which matters for projects with a defined service life followed by demobilisation. Buildings can be single, double, triple or more storeys, in I, U, L or courtyard layouts.
The two standard module sizes are 6055 × 2990 × 2896 mm (internal 5845 × 2780 × 2500 mm) and 6055 × 2435 × 2896 mm (internal 5845 × 2225 × 2520 mm). Frames are galvanised cold-formed steel t=3.0 mm in SGH340, factory prefabricated. Roof and floor insulation is 100 mm glass wool; walls use 75 mm colour-steel sandwich panels and seamless S-type rock wool composite panels. Electrical circuits are pre-fitted in the roof, water supply runs along the walls, and drainage is wall-side — services are substantially complete on arrival. Typical applications include engineering camps, commercial buildings, emergency facilities, education facilities and military sites.
The same module platform is available in two format variants: flat pack (the 6055 mm standard box packed flat for transport and assembled on site) and detachable (bolted, demountable modules that can be taken apart and reused).
Specification comparison
| Parameter | ZA Series | ZM Series | Modular house |
|---|---|---|---|
| Structure | Hot-galvanised cold-formed steel, T=2–3 mm | M300 columns T=3.0 mm; C170 purlins T=2.3 mm | Galvanised cold-formed steel t=3.0 mm, SGH340 |
| Span / layout | Up to 12 m | 12 / 15 / 18 m | Standard modules, multi-storey, I/U/L/courtyard |
| Eaves height | Up to 3.5 m (accommodation/office); up to 4.5 m (storage) | 6 m | Module height 2896 mm |
| Column spacing | 3.45 m | 4 m or 6 m | Module-based |
| Roof live load | 0.50 kN/m² | 0.3 kN/m² (6 m spacing); 0.50 kN/m² (4 m spacing) | 1.0 / 0.5 kN/m² |
| Wind load | 0.45 kN/m² | 0.45 / 0.60 kN/m² | 0.6 / 0.5 kN/m² |
| Snow load | — | 0.35 / 0.50 kN/m² | — |
| Floor live load | — | — | 2.0 kN/m² |
| Working temperature | -25 °C to +50 °C | — | — |
| Erection rate | 4 workers, approx. 40 m²/day | 10 workers, approx. 1,000 m² in 5 days | Bolted module assembly on site |
| Shipping density | Approx. 200 m² per 40 ft container | Approx. 170 m² per 40 ft container | Module-dependent; flat pack variant reduces volume |
Load figures are system design values and must be checked against the project’s site conditions during engineering review. Snow load is not stated for the ZA and modular systems in the base specification; where snow is a design case, confirm requirements with the engineering team before tender.
Pros and cons by system
The advantages of prefab homes are usually described in general terms, but they vary by system. The table below sets out what each family does well and where its limits lie.
| System | Advantages | Constraints to plan for |
|---|---|---|
| ZA Series | Highly prefabricated; fast panelised installation; flexible internal layout with fit-out options from bathrooms to open-plan offices; corrosion-resistant, well-insulated wall panels; 12 m span and up to 4.5 m eaves for storage | Column spacing fixed at 3.45 m in the standard configuration; not intended as a wide-span clear-floor solution |
| ZM Series | Clear spans to 18 m; 6 m eaves; high daily erection output with a ten-person crew; efficient shipping density for large floor plates | Roof live load depends on column spacing (4 m vs 6 m); wind capacity is listed separately in the series data — spacing must be fixed early; suited to storage and workshop use rather than fine internal subdivision |
| Modular | Highest factory completion; services pre-fitted; relocatable and reusable; multi-storey and courtyard layouts; format variants (flat pack, detachable) | Layout constrained by standard module dimensions; transport and lifting planning required; detachable variant should be specified from the outset if demountability is a requirement |
Across all three systems, the general pros of prefab construction hold: factory manufacturing runs in parallel with site works, quality control happens in a controlled environment, and site labour demand is reduced compared with conventional construction. The cons are equally consistent: design decisions must be frozen earlier than in stick-built construction, transport logistics form part of the design brief, and site preparation must be complete before erection begins. Buyers should also confirm certification scope for their market — CDPH holds CE certification for modular container houses, prefab houses and light steel villas, ISO 14001 and ISO 45001, product carbon footprint certification, National High-Tech Enterprise status, NATA materials certification for Australia, Intertek fire-resistance certification, CCS factory approval, and Intertek ICC-ES / WH building-material compliance for the US market. Certificates available upon request.
Timelines: how a prefab home project actually runs
Project buyers often ask for a single delivery figure. The honest answer is that prefab timelines are a sequence of overlapping phases, and the critical path usually runs through design approval and site readiness rather than factory output. Four phases matter:
- Engineering review and quotation. Every project is quoted individually after engineering review. The team replies within one business day with a concept proposal and a budget range, which gives an early basis for programming.
- Design freeze and approvals. Layouts, spans, openings and fit-out are confirmed. Because factory production is design-led, changes after this point carry schedule consequences — the earlier the freeze, the more reliable the programme.
- Factory production, overlapping site preparation. This is where prefabrication earns its time advantage: manufacturing proceeds while foundations and site works are completed in parallel. Production duration depends on system and quantity, and is confirmed in the project quotation rather than published as a fixed figure.
- Shipping and erection. Shipping density is known per system (approximately 200 m² per 40 ft container for the ZA Series, approximately 170 m² for the ZM Series), so container counts and vessel bookings can be planned from the drawings. Erection rates are also defined: four workers erect about 40 m² of ZA structure per day; ten workers erect about 1,000 m² of ZM structure in five days. Modular units are bolted together on site, with the format variant determining assembly method.
For projects with a hard handover date, the practical recommendation is to engage engineering review early, freeze the design before production slots are booked, and sequence site preparation so that erection crews are never waiting on groundworks. CDPH does not publish fixed delivery day counts because every project is quoted individually — the programme in the quotation is built from the actual scope, shipping route and site conditions.
Manufacturing background and project experience
Beijing Chengdong International Modular Housing Corporation (brand CDPH) was founded in 2009 and operates as a project-based manufacturer. Production runs across three bases — Hebei, Xinjiang and Sichuan — supported by 13 subsidiaries and offices, more than 100 engineers and a team of over 500 people. The Hebei base is 48 km from Tianjin Port, which supports export logistics. CDPH reports more than 5,000 projects implemented in over 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.
Representative project types, by region and sector, include a port expansion camp in Côte 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 whose fire performance was verified by Intertek testing. These references illustrate the range of climates and sectors the systems are specified into — from extreme cold to desert heat — and the corresponding load and insulation requirements. Fourteen key welders are qualified to AWS, CWB and CE standards.
Next steps for project buyers
To move from system comparison to a quotation, prepare the following for engineering review: intended use and occupancy, required spans and eaves heights, storey count, site location and design loads (wind, snow, seismic where applicable), fit-out scope, and required certification for the destination market. With those inputs, the team can confirm the appropriate system — ZA, ZM or modular — and issue a concept proposal with a budget range within one business day. To start the process, contact the CDPH engineering and sales team; certificates, including CE, ISO, NATA, Intertek and CCS documentation, are available on request.