For one thing this old house has unleveled floors the house is going to the middle. I am sure a waterbed has to be level as well as good support beams in the basement. I don't know about those things.;)
I used to have a waterbed and loved it for years. The rule of thumb is: if you could fill up your bathtub the floor shold be strong enough to suppot one. Condidering the typical water bed is around 7 ft x f ft (49 sq ft)and the bed holds around 150 gallons of water (1050 pounds) , the dispalcement of weight on existing floor space should be around 21.5 pounds per square foot.
Standard rule of thumb is if you can have a grand piano, you can have a waterbed. What people don’t consider is the distribution of the weight per square foot allows a waterbed just about anywhere.
I remember talking about it with you before. It performed miracles with my arthritis and I have some pretty wonderful testimonials from other people.
Open bag, no baffles, provides complete support with no pressure points. It’s more comfy than being in vitro.