3d Model gets disconnected from raft support everytime

Hello
I just got Creality ender 5 plus. Started printing with PETG material and i keep geting bad results when printing stuff for long duration. If i print small stuff from 1 to 2 hours its oky. But if i start printing big stuff like boxes or some handles for my switch, corners gets disconnected from raft support and raft support has very good connection to the bed, u cant get it of if its hot, Just the models keeps disconnecting from it. I dont know what to do, what to correct. I must say i dont have printer in a room its kinda in a hallway in the basement, cant put it anywere else. Temperature in hallways is around 18 to 20 degres celsious. My settings are 230 for the nozzle and 80 to 90 for the bed. This settings are suggested from factory that i use PETG. My fan speed is 60-100. Print speed is 100 %, wall thicknes is 1.6, infil densitiy is 20 and infil is cubic, layer height is 0.2 and my nozzle is 0.4.
Do u think it would be smart to make enclosure for this kind of enviorment that my printer is living in? and what are your suggestions?
Lp Jure