As a landlord, you are liable for repairs to keep the place safe, any costs you incur for this comes out the rent pot therefore paying less tax on "profit"
So if I have to pay an electrician or joiner or builder etc to do any work in any of our rentals then the sum paid out is tax deductible and the trades person sorts their own tax payment, obviously the more I pay them the more tax they pay, if I do gas or plumbing in any of the flats my accountant said I could pay myself as well but I would need to pay reasonable rates and pay the relevant tax, he decided the best result (ie at the end of the day which way gave me most cash in my pocket) was to do the gas and plumbing at material cost only, so that I didn't pay any tax on it, he said it wasn't worth the bother of paying myself to do it the. He worked out the tax due, because we run the properties through our business none of take any wage at all, all profit is divided into dividends to reduce NI and increase money into the family pot, as the main shareholder and main earner I quite often don't take a dividend, my son never takes anything, so this leaves more profit which can be spilt up between the other share holders, my mum, wife and daughter as they have less existing tax burdens, then the three of them buy me things, all perfectly legal and above board