I don't own a Roo but I have owned tents. I assume the canvas on a Roo is pretty much the same as a tent. From the time I was a little boy I can always remember being told, do not touch the canvas when it is raining as it will start leaking there. Also, try to make sure other things, ie.. Mattresses or what ever are not up against the canvas as it will,cause the canvas to leak.
I agree with other posts here as far as waterproofing the seams and it might be good to apply a good canvas sealant on you Roo.
It is no fun to sleep in a wet bed.. Good luck
2016 Siverback 33IK
2015 Ford F-250 Lariat 6.7L V8 Diesel 4WD Super Cab
"If you don't know where you are going, any road will get you there."