UFH pipe design and spacing - 300mm?

[Conor]

I'm playing around with loopcad. I'm assuming a standard serpentine design is the easiest to install? I can see how part of the floor would be warmer than other parts, but does this matter with 100mm S&C screed?

 

We're building to passive standard and I know the UFH won't be used much. I'm struggling to get less than <10w/m² output from the system with an 11c delta and 200mm spacing. I can see rooms overheating very quickly.

 

300mm spacing seems to work much better. I know it's wider than standard, but any reason not to if I don't need the heat output?

[ProDave]

If the heat output is too great at 11c delta, reduce the flow temperature?

 

In any event the room thermostat will turn it all off when the room gets to the desired temperature.