ᐅ Walls made of extruded polystyrene (XPS) or expanded polystyrene (EPS)?

I want to build a small lightweight house. It should be normally livable but must weigh very, very little for certain reasons. The house will be single-story, with a maximum of one upper floor. However, the upper floor will only have one room. I do NOT need building permits/planning permission or structural engineering. Initially, I planned a wooden timber frame construction. Simple wooden stud framing, with insulation (Isover) placed between the studs, a vapor barrier on the inside, and drywall, and on the outside, a breathable roofing membrane and wooden cladding (or similar). Finished.

Now I saw that someone built a house using laminate panels. However, it looks like the walls consist of glued Styrofoam (or another brand) panels that are then covered with laminate. Would it not be possible to do this without laminate? For example, by simply gluing together 20 cm (8 inches) Styrofoam blocks? Would windows hold properly in that? What are your opinions or solutions for my problem? I don’t think I can upload photos yet?????

Walls made ONLY of Styrodur or Styrofoam? Seriously?

How is that supposed to hold up?

Have you ever, for example, had a bicycle fall over and hit a wall insulated with Styrofoam? That will likely leave noticeable holes in the insulation, even if the plaster above was reinforced with a mesh...

I can’t imagine that this type of construction would be durable...

Are you sure the house you saw wasn’t built with polystyrene blocks that were later filled with concrete?
A pure polystyrene house won’t be able to support the roof permanently.

How large is the “house” supposed to be? An actual dwelling with windows, or just a garden shed? Or a structure on a houseboat? In the latter case, Archimedes’ principle helps, so weight is less of an issue.

What is the target “weight” goal?

I would also be interested to know for what reasons the house is allowed to "weigh very, very little"?

After all, at the end of the day... it’s a house?!

Yes, it is about a proper house of approximately 100 m² (1,076 sq ft). There is no minimum size limit to be met. The focus is only on maximum lightweight construction. I am familiar with Styrodur, so I know it is very stable. Whether an inner gypsum board layer is still needed and some kind of external protection is required is another matter. Unfortunately, I cannot attach any photos; otherwise, I would show a model house that is self-supporting and stable on its own.

Photo (or is it possible after all?)