People often use "prefab house" as an umbrella term for anything that isn't traditional masonry construction — including timber-frame houses and SIP panel houses. The difference between them, though, is significant, and it affects price, speed, and build quality.
What a classic prefab (timber-frame) house is
A traditional prefab house is built from individual timber studs and beams, either assembled on site or partially framed off-site, then insulated afterward with mineral wool or another material. The precision and quality of this type of build depends heavily on the skill of the crew working directly on site.
What a SIP house is
SIP (Structural Insulated Panel) works on a different principle — structural strength and thermal insulation are combined during manufacturing, into a single sandwich panel (EGGER OSB board – Austrotherm EPS 70 Grey insulation core – OSB board). The panel is manufactured in a factory to exact specifications and arrives on site ready for assembly.
Direct comparison
| Parameter | Classic prefab (timber-frame) | SIP house |
|---|---|---|
| Where precision happens | Partly on site | In the factory |
| Thermal insulation | Added afterward (mineral wool, etc.) | Built into the panel during manufacturing |
| Shell construction speed | Weeks, weather-dependent | 30 days production + ~14 days assembly |
| Airtightness and thermal bridging | Depends on on-site build quality | Lower risk due to factory sandwich construction |
| Price predictability | Can shift during construction | Easier to define in advance after the project scope is confirmed |
| Suitable for self-building | Common | Possible with a standalone SIP kit |
When a classic prefab house makes sense
If you have your own experienced timber-frame crew and aren't under time pressure, a classic timber-frame build can offer more flexibility for non-standard architectural solutions.
When SIP technology makes sense
- When you need a predictable completion date
- When you want a clearer budget before construction begins — see our turnkey house pricing
- When consistent, high-quality thermal insulation matters, regardless of on-site labour quality
- For smaller structures (Tiny Houses, garden cabins), where manufacturing and assembly speed is a particularly strong advantage
For a full breakdown of the technology's strengths and limitations, see SIP panels: pros and cons.
Summary
Both approaches fall under the broad "prefab" category, but SIP technology moves the critical work from the building site into a controlled factory environment — meaning greater precision, a shorter build time, and a firmer price upfront.