Some windows the slit is on the side, but most of the windows have the slit at the top. All windows have at least two weep holes on bottom. Some slits are factory caulked on the inside slightly. I noticed just tonight a small window that had a slight gap on top frame. Didn't like the looks of it. I put some RV pro flex on it for now, maybe dealer can take a look at it this winter. I did a messy job, but its sealed.