Note that for a piston to sit securely in a cylinder without tipping, it has to be sufficiently long compared to the diameter of the cylinder. If you start making huge diameter pistons, you'll need them to be long, too. The volume of the piston would become huge, and it would be heavy and expensive. And hard to fit where you need it.

That might mean that you'd want many moderate size pistons instead of one giant one to lift a house. You could pipe them all the the same pump, and you wouldn't need any extra pressure because of the many pistons connected, assuming they are plumbed in parallel. You'd just need many pump strokes to move them a significant distance.

Laplace's Law - the greater the radius of a cylinder, the greater the wall stress. More formally, stress = Pressure × radius / thickness as long as thickness is less than 10% of radius.

To generate a very high force, you would need very high pressure and radius, which in turn means you either need very thick walls or very strong material to prevent failure. Neither is impossible but both are expensive.

In principle, you could.

The force on the pump only depends on the pressure (for the pump of a given size), so that is fine.

Larger piston just means you have to pump large volume of fluid, so you have to be patient.

Of course making a sufficiently large hydraulic cylinder and putting it under your house might turn out to be impractical.

[removed]

[removed]

[removed]

[removed]

[removed]

I think the limiting factor is kindof as much a practical one as it is a material one. A relatively tiny pump will take an impractical amount of time to do a job, because there will be an operational speed limit for the pump.

In practice, when houses are lifted with hydraulics, it is with many small cylinders because the load map underneath a house is not uniform.