Thanks. That's really helpful to know. 

hi, anyone have a solution for a 2011 focus hatchback? I'm suffering the same problem. there are no high vents in the boot of the hatchback, I've had the seals re sealed around this time last year. the water seems to be coming from the left hand corner of the boot closest to where you stand, there is no wet patches from the top off the boot just the bottom.

@trebor4482 about to do repair. any leaks a couple months on?

I’ve had the same problem. I’ve used some clear sealant around the boot latches and along the metal welds around the boot and the rubbish cork like seal just below the roof bar. I’ve not gone to the extent of removing the roof bars yet. See if this works first. 

regarding leak through rear vent on focus estate there is a strip of panel filler on both sides of the  rear top hinge panel which fills in the gap between it and the 2 side panels, it starts at the back end of the roof rails and ends at the rubber rear door seal  can look a cream colour. this filler material

can become porous i have found this is what the cause was on my car.  i cured this by drying and cleaning around them then using clear silicone

sealer all along the join from roof rail end to under rear door rubber

 

if you remove the grill the side where the leak is ,to check whether the roof rail is leaking inside  push your arm up between liner and side untill you feel the last roof bolt and feel if it is wet if not then leak could be the panel sealing filler 

me too they are 4 10mm nuts per side that are quite long, they are located about here as illustrated as well as where I put down the sealant.

Hi there everyone I have had the same issue the problem is deteriated seals under the tailgate hinges, 99% sure it is unlikely to be the roof rails took mine out no sign of any ingress on the seam but sealed them both anyway.

 

Good Luck

John (Omegabase )

Dreaded drips through rear vents appeared.  Did the usual easy seals first, (hinges, struts, checked lights) found nothing amiss really and leak continued.  Followed Trebor 4482 post with interest as my visible seams at top of boot had deffo dried out and cracked.  Decided to drop headlining and remove roof rails to check.  Seam filler at the very rear and very front of the rail channel had cracked with a visible gap approx 5mm long.  Cleaned re-sealed and refitted rails and headlining.  I now await the rain !  Here's hoping !!!  Added a few photies, hopefully you can make out the cracks