I’m in a similar situation at the moment, but the figures are a lot lower.
We want to build a new house. We’ve bought the plot, foundations are finished, we have no money left, so want to borrow £100k to finish it.
My current house is worth around 230k. I owe £20k on it. So roughly 200k equity in the house. I thought it would be easy to get a loan for that, as, clearly, the risk is very low. However, banks see it rather differently. I just cannot get a loan. Tried various banks/BS’s and 2 Brokers, none of them can help. It is affordability. I’m 58, and they say I cannot afford a loan of £100k over 10 years (it wont be 10yrs, it’ll be a maximum of a year, then we’ll sell my house and pay it off). The most they’ll give me is £44k, which doesnt help at all. Short term loans hold no interest for them, as they have to still account for paying it off each month, which would be impossible for such a loan. I’ve been told there are some private investors who will lend against the house, but they are specialist, and will charge a very high APR, and there are lots of hoops to get such a loan, and even finding someone to do it is difficult.
I think you will be in the same situation unless your income is enough to be able to pay off the loan. Oh, another thing, all of them said they wont be doing interest only loans/mortgages, and another we tried, a bridging loan, but that had.a life limit (18 months iirc) and an APR around double the mortgage rate, as well as only allowing around 30% of the value of the property.