Home financing with another property

Ah, I see. Then that's good :)

I am not a tax expert. However, I would definitely review the constellation from a tax perspective regarding deductibility. From the bank's point of view, you are not financing the two existing condominiums [ETW‘s], but your house construction, and the two condominiums serve as substitute collateral. Because the two existing ones already exist. I don't know to what extent the tax authorities will accept this. But basically, this should not be a problem for a bank... at most because two collaterals have to be assessed and not just one. But just discuss it with the bank.

Don't know to what extent the tax authorities will accept that.

That doesn't matter at first for the financing itself. However, for the bank it's great (except maybe an online direct bank that struggles with multiple properties - I know that myself). As far as I know, deductibility should also not be a problem. Purpose: equity refinancing and then it's all settled. Many of my clients do it like that too. First buy and pay from equity and then later calmly look for a bank - and it's not about such "peanuts" as here.