"Never do a makeshift" - believe it for a long time
I was recently with a friend, I saw such an extension, I was very surprised, now I will explain the situation.
Background
The family came from Donbass, a friend has relatives here, at first they lived with them, and then they took out a mortgage and bought a small house in the private sector. Naturally, people stretch as best they can, it is necessary to repay debts and equip life.
Annex
A friend called me to see how to make electrical wiring in the extension (I help him with my profiles), and then I saw it. Assembled from a bar and sheathed with OSB on both sides, insulation between them.
I was honestly surprised, since last time I saw he has a capital foundation for an extension, it was logical to lay out the walls of stone. Friend said it was a temporary structure, and when the financial issue is resolved, he will convert it to stone.
I am sorry to look at this, because funds were spent on "temporary" materials, but you could immediately buy "permanent" ones.
But you still need to finish everything inside, and throw the wiring, also a pretty penny. Two windows and a door will be installed, which, during alteration, will need to be carefully dismantled, not the fact that it will work out successfully.
Conclusion
I have doubts that it will be redone, as people say, there is nothing more permanent than temporary! I personally advise that it is better to immediately save up for normal material.