In order to work out what borrowing the rent will support, and if there is possible cash-flow from the rent, you can do various different calculations to work this out.  This ultimately indicates whether a deal is a "deal" or not.

Generally speaking, deals only stack when you have achieved a significant discount from the genuine Open Market Value of the property.

We use the following quick calculation:

monthly rent x 12 divided by (product interest rate) divided by (product rental stress)

We have some stacking software included in our Investor's Kit which you can purchase in our on-line shop.