Could I ask for those Grade II listed flats which required to pay up a 15k for the major work such as replace window and painting the building wall etc. are they deductible in any sense?
I think i heard somewhere that it is not deductible neither expense nor capital. is that true?
I don’t know where you heard that, but I can’t see why major works could not be offset against CGT when a rental property is sold. There may even be a case for it being a revenue expense to be offset against rental income.
If they are repairs (eg painting), including replacing with the modern equivalent (eg upgrading from single to double glazing etc) then they are deductible from rental income.
They would not be deductible for capital gains unless they are improvements.
I had had an HMRC enquiry on a client’s capital gain where HMRC argued that a kitchen replacement was revenue not capital. We managed to argue back against them on a lot of the cost because they has extended the kitchen and added lots more units/higher spec etc.
You may be able to argue costs as capital if you paid less for the property because the work needed doing and it was not useable without.