There is a nice video below detailing how to do this easily.
Shed floor insulation.
This will be according to your shed plans.
Measure the distance between the floor joists.
Insulating a shed floor is not one of the first things that comes to mind when insulating a small building.
Budget ability and experience also.
The best way to insulate a shed floor is in the building phase of the shed.
Access to the underside of the floor though affects the options available for insulating it.
Insulating a shed will reduce damage to your stored tools equipment or boxes.
Insulating the shed floor will help create a thermal barrier between the inside and outside air spaces.
It can also make it more versatile allowing you to store plants or use it as a rec room.
How to insulate a shed.
Insulating the walls would be simple because they were exposed to the inside and insulation batting could easily be squished between the studs.
I have a friend who lifted his unfinished shed to permit the floor to be insulated then lowered it back down.
However having a layer of insulation beneath the floor boards will contribute towards keeping the contents of the shed toasty.
One of the drawbacks for spray foam is that you need backing for it to adhere to the surface.
Is an effective but more expensive solution for floor insulation in your shed.
I recommend foam boards as they can be cut to fit between the floor joists easily.
Warm air rises and so naturally the walls and the roof are the first areas to consider.