How is it possible to borrow for building a house without falling into usury, knowing that available loans have interest and that the house will cost around 30,0 US dollars?

We do not know of a specific entity that assists with what you requested, and this is not within our purview. You have done well by avoiding interest-based borrowing, as it is one of the gravest sins, and its consequence is deprivation and a lack of blessing. Allah has threatened those who consume it with war, and has promised the pious ease, facilitation, and provision from where they do not expect. We have explained the impermissibility of borrowing with interest to purchase a home. You can consult an Islamic bank. We ask Allah to grant you ease and facilitation.