If you are hell-bent on getting out of this lease, then you should mail a letter outlining the problem to the landlord and explain that it makes the apartment inhabitable for you. Have your agent follow-up this letter up for you if your LL does not speak english.
The LL has a responsibility to ensure the apartment is in a habitable condition and if there are any structural defects that arise (that are not due to the negligence or fault of the tenant) the landlord must rectify them within a reasonable amount of time. This reasonable amount of time would commence from the date the LL receives your letter.
Have a read of this document (it is ~10Mb):
and refer to page 11.
You should make sure that the problem is in fact a "structural" or inherent problem with the unit, rather than a case of a dead fish under your sink (which would then make it your responsibility, not the LL's).
Sometimes LL's need a kick in the pants to get moving on these things, plus the LL will have more influence on the Building Management to get it fixed if it is in fact a common-area problem.
Read your Tenancy Agreement carefully to find a clause relating to the LL's duty to maintain the structural portion of the unit.
This is not legal advice, but I know someone that followed this path in the past to get the landlord to act. Hope it helps.