I’m under contract for a sfr in SA and I could kick myself – the roof is at the end of its life at only 18 years, but the owners quickly patched up the few loose tiles within 24 hours and pretend like everything’s okay, and what can I do now?

If it is a realtor, as Mike pointed out, a realtor is bound by code of ethics.

I think a written lease would convey, and I'd be bound by any terms in it, so I asked my agent to get, in writing, assurance that no written lease exists.

A private money or pure asset based hard money lender may be a better option since they aren't bound by the same regulatory environment as a bank.

My question seems dumb - should we risk to buy a 1.5-1.7M newer SF and to be bound to the mortgage forever and work our whole life to pay for it, or should we buy a SF around 1.3-1.4M which has much worse condition comparing with the above?

The full commission is paid either way.Not to mention that if you deal directly with the seller's agent, you're negotiating with someone who is bound by law and by ethics to get the best possible deal for his client - the SELLER.

properties ...dont loose hope.

1st guy to run out of nasty toilets looses?

And other half x-girlfriend looses her share?

But at the price you are paying you don't have much to loose and if all goes well you'll have an excellent return on your investment.