I think the best thing to do is get estimates for all the repairs with a start date for each. That might take some time in this economy. Mail them to your landlord return receipt requested. Include a statement that since it is the landlord’s responsibility to keep up the building, you intend bill him for the cost. When he doesn’t respond, go ahead and start them. Pay by yourselves, submit the invoices to the landlord for the completed work and tell him you will then deduct from your rent. Just keep copies of all your correspondence in case he tries to evict you. Who knows, he might be happy someone else is doing the upkeep.