We need a structure for the inner walls and outer walls as well. Instead of making 2 structures (or choosing a thick brick wall) that insulates nothing our approach is different.
Tego / plywood tightened with screws to our metal columns. Check it out on the drawing below. If no thick heavy walls that means no thick heavy foundations needed.
This is a plan with the boxes at the shorter parts. The red lines are the strong tego / plywood for a semi structure to hold the lightweight façade. And the red small rectangles are the columns.
The blue represents wood. That helps to fix the façade. It’s way cheaper this way than buying 90* metal corners. This way cost maybe 1/5.
On the image down we have the interior, bathroom. Up we have the exterior. Within the box we have the insulation and the false facade. Within the same box, under the false facade we have the electrical equipment. I show a simplified version.
It depends on the materials chosen as finishes on the facade. We used wood so it can be fixed directly with screws. We can use triangles instead of rectangular sections. The wooden triangles help us fix our facade to the tego / plywood.
Choosing a triangular section (instead of a rectangular one) means we need maybe half of the wood. At the exteriors : where the forces are small I would go with this triangular version.
Highly recommend reading this:
Chimney effect. Check out the link above. The layers complicate a bit. We use the chimney effect. The heat from the Sun won’t get to the insulation. Moving air between the facade and insulation will let the hot air escape.
Rectangular chicken wire … or any other wire mesh system could hold the insulation in place. It won’t “fall” on the “chimney effect”. Fences in general are great for the task. Note that we need additional membranes. The house needs to breathe, evaporate from the inside. Meanwhile the membranes shouldn’t let water droplets and dust towards the interior.
Basically we have a double facade. Air can pass between them freely. The upper part is open … and the lower part is open as well. It will work as a chimney. The warmer the facade gets … faster the hot air will leave the house.
The house won’t radiate back heat in the evenings. None of thermal mass in the walls. None of sleepless nights and air conditioning. In case we really want to preserve energy for night time …we can pour a thick layer of concrete / rock mix as a floor.
Right on the metal beams. (above insulation). So We’ll have an extremely well-insulated passive house with an insanely huge thermal battery.
In summer time the shaders can come down. Nothing will overheat.
You see a simplified version of the bathroom area. The black is the metal poles that are structural. The blue is the wooden columns. At right you can see the chimney effect. The niche for it. At the upper part of the image you see the place for the electric cables and machinery. At the left it can be a shoe box between the bathroom and entrance.
Note that’s a simplified version to get to the main idea.
Note that this niche (false façade) is just perfect for wires. They are protected from the sun and rain. Easy access. We can reorganize them anytime without a hustle. That’s nearly “impossible” in case of a normal house.
Cables can run up and down not just within the false facade. they can do it in the thin metal frames as well. (between the windows). An elegant solution. We can take shortcuts from the ceiling to the “basement” this way. Heaven for electricians 🙂
This box seems a bit complicated at first sight … but it’s not. The main idea is a tego / plywood is on the metal frame. And everything else is on the plywood. Within this design … we have these huge “boxes” positioned at the shorter facade. Half of it is insulation. And the other part is for electric gadgets. Easy access.
Water pipes could be embedded within the insulation. In case of a vacation home we can drain the pipes before leaving. We could add a small electric wire that keeps it above freezing temperatures at all times.
Regarding the mist spraying system (that kills fire on an instant) : consider a self-draining system. So after the high pressure pump stops … the water will drain out by itself. (Not that we want it to function periodically).
Check out the wall between the kitchen and bathroom / entrance. It’s super lightweight and thin. This version is made for a person or couple. In case of a heavy duty :)) 10 kid family it should be thicker. Don’t get lost in the details here. Think about the solutions.