Why is a prefab plan different?
The walls of a prefab house are panels made in a factory. Since panels come in set widths, choosing wall lengths close to multiples of that width makes the job easier and reduces cutting and waste. Dimensions vary by manufacturer. For example, the technical specification of Karmod, one of the manufacturers in Turkey, gives the outer wall panel as 10 cm, the inner wall panel as 6 cm, the panel height as 250 cm and the panel width as 125 cm. Before you start your plan, ask your chosen manufacturer for their dimensions.
Thin walls enlarge the inner dimensions
In a reinforced concrete house the outer wall is often more than 20 cm thick. Prefab walls are thinner, so the same outer dimensions give a larger interior. That’s why a prefab house floor plan should be based on the inner dimensions, not the outer ones: the inner dimensions tell you whether the bed and wardrobe fit.
Example: two-bedroom prefab, 66 m² net
| Space | Inside dimension | Area |
|---|---|---|
| Living room + open kitchen | 5.28 × 4.08 m | 21.5 m² |
| Bedroom 1 | 2.88 × 4.08 m | 11.8 m² |
| Bedroom 2 | 4.08 × 2.88 m | 11.8 m² |
| Bathroom | 2.28 × 2.88 m | 6.6 m² |
| Pantry | 1.68 × 2.88 m | 4.8 m² |
| Hall | 8.28 × 1.20 m | 9.9 m² |
Prefab floor plan step by step
- Find out the manufacturer’s panel size and wall thickness.
- Choose outer dimensions close to multiples of the panel width.
- Place the rooms by their inner dimensions. In Nodaform, set the wall thickness to your own value; inner dimensions and areas are calculated from it.
- Group the wet areas together. The bathroom and kitchen plumbing stays short.
- Line up doors and windows with the panel joints. The manufacturer cuts the panels accordingly.
A container home is another option
If you’re looking for something smaller and movable, read the shipping container home floor plan post: inner dimensions of 20 and 40 ft containers and two ready-made plans.
The plans and dimensions in this post are layout ideas. A building permit, structural design or construction project requires a design by, and approval from, a licensed architect and engineer; ask your municipality about the details of the regulations.