Hi Rtmt,
Contractors and IDs like myself usually provide this service, a short and quick visual inspection(10-20 mins), when they are on site for measurement or for quotation's sake. A full detailed inspection, marking, and filling up of the rectification form would cost from 400 - 600 depending on the size of your flat; such inspection usually takes up to about 6 hours.
Best and Warmest Regards,
Wilson Choo
Homebox Studios Pte. Ltd.