Building Homes or Extensions/waterbed
How can I tell if the main floor can handle a king size waterbed with frame houses was built in 1965 and was moved in 1995 with A basement
You will need to know the floor construction (timber/concrete, etc.) It's thickness and span. You should be able to get the weight of the bed from the manufacturers datasheet, but if not it's quite easy to work out. One square meter of water weighs 1000kg. So just work out the volume in cubic meters and you can easily find the weight.
You should probably ask an architect, surveyor or structural engineer to do the calculation for you just to be safe. If the floor isn't strong enough, you may be able to strengthen the area supporting the bed.