Wood burning boiler

I have a 60x40 building with pex tubing in the concrete floor. I am going to install a wood burner boiler as a heat source. Do I need an additional tank for water storage in addition to the capacity of the boiler itself?

Definitely. Even with a well controlled automatic boiler they can modulate only down to 30%, so you need a store of several thousand litres, or around 100 cu ft depending on the size of the boiler. However, good log boilers are not cheap.