What type of flat roof covering is the best?

[70sCarpet]

My loft-conversion flat roof is now leaking in heavy rain. I think we did quite well getting 24years out of the original felted roof. I'm wondering now what is the best material to re-cover it with? My neighbours went for some kind of poured resin on theirs. I have another neighbour opposite who seems to have zinc sheeting. The size is around 20sft. What material will give me the best roof?

I used to have lead on part of my commercial premises. It is a very good covering, but expensive, and was stolen twice.

It is now covered in synthetic rubber which I'm told is a very good roof.

If your flat roof has been leaking it will need a new deck, and this is a good time to upgrade the insulation as well.

EPDM (rubber), GRP (fibreglass, probably the poured resin look your neighbour has) or single ply membrane, are probably your options. I would expect price to go from lower to higher based on that list, with longevity correlating to price. Zinc is expensive and can corrode, lead is very very expensive and not worth it unless it's a historic building - and does get pinched all the time.