Joints in screed / concrete slab

[jesteh]

I have a floor area thats L-shaped with long sides being 6 and 7meters and width of the floor at 3m.

Should I be concerned about having any sort of expansion joints put into floor at that size? The concrete slab has been laid already with builder not really doing anything other than just pouring concrete in and flattening it down. Screed is yet to be done including underfloor heating and again there are no plans to use any sort of joints in concrete.
Is that generally ok based on dimensions?

 

[noseall]

I have never come across the need for e.j.'s within internal domestic structures nor have i seen them specified.

 

[mointainwalker]

It's been a while since i did it, but am fairly certain that my UFH called for ej's in doorways and where any room exceeded 30 m2 or length was greater than 7 m (?) for traditional screed.