Soft spot

[Mike72]

Does anyone have any tips or suggestions on how to repair a soft spot on my 268RKS ? It’s in the bedroom and it was there when we bought it used but I didn’t really notice it . Is it possible to repair or reinforce from below ? It’s between the bed and the wall , so I was thinking of trying to lift up the vinyl floor in just that area and cutting out the bad piece . Any suggestions?
Thanks
Mike

[5picker]

Any idea of the floor construction?

Is it plywood underlayment or the often used sandwich sub floor of two thin sheets of Luan with Styrofoam in between?

Have you repaired the leak that caused the soft floor?

[Thomas ho]

i used a honeycomd plastic beer advertisment sign foam board, liquid nails.