kiwi

hey guys i was grinding all the rust off the floor of my RR today getting it ready for some new carpet and as usual i got side tracked and ended up ripping out the entire aircon/heater matrix (wasn't hooked up or working anyway) but now iv ran into a little problem i can now put my hand up through the vent an touch the grill at the bottom of the window screen and im thinking when it rains waters going to come pouring in?? has anyone else ripped there one out?? or has anyone got any ideas of what i could do to stop water coming in??
Cheers.