the agent is lying, you will know this as there lips are moving...
now that we have established that the sellers aren't moving to Antartica to start a summer zen retreat we can focus on the house.
1) plans are legal reqirements, if the current plans held aren't the same as the house as it is currently, then the municipality is perfectly in it's rights to knock down what is not approved.
2) you will need to have new plans drawn up and then sent for approval etc, this takes months as you can imagine. And if there is even something simple as a skylight, well then you suddenly need structural engineers to come in and approve them as well.
3) once all that is done let's focus on the moist box... damp in one area of the house can be fixed no problem. Maybe there is no DPC there or the room was used as a greenhouse etc etc. A new silicone DPC can be injected into the wall.
4) If you like the house then work out what the damp repair will cost plus your wasted time in doing this. So if it's R10,000 then make it R20,000.
5) plans <-- do not buy without approved plans
6) in your OTP just stipulate what you want, and ALWAYS make a "the house transfer must be completed in a reasonable time frame to a maximum of 6 months.." <-- something on those lines.