I own several BTL properties. However I have v little mortgage borrowing in them and none on my main residence. It’s not something to take lightly and the changing tax rules make it a less desirable proposition.
Make sure you can get a fixed mortgage deal so this element is predictable.
Consider the tax implications (far fewer expenses are deductible when calculating your profit).
What might happen if you have a lengthy period of no rental income either because the property is empty or your tenants stop paying? (Most of 2020 I had no income).
What reserves do you have for repairs, insurance, maintenance, legal costs for evictions?
Are you in a position to get a plumber to fix a boiler when you receive a call from your tenant when you are waiting for a flight to go on holiday (real life scenario)? Or will you get a manager (if so deduct a further 10%).
Other expenses: insurance, gas and electricity certificates, possible HMO licence depending on type of property.
Can you afford the costs of purchase? The capital gains tax payable at the other end (likely to be aligned with marginal income tax rates shortly)?
After all this will you have a markedly increased income? Worth the hassle, time and potential heartache?
Or is it worth seeing a good IFA and seeing if there’s another way to secure additional income?