FWC light leak

[Smars00l]

I recently purchased a used FWC Granby. It’s been stored outside with the pop up closed until last night, when I popped that baby up. This morning, one of the light fixtures over the bench seat has leaked a good amount of water around it. I don’t see any damage to the ceiling liner. I’m frustrated bc I had this EXACT same issue in my Phoenix camper. Any ideas on how to fix this or am I in a huge money hole now? Thx!

 

[Vic Harder]

So the ceiling liner is not wet/discolored? Does your Grandby roof have screws or is it the newer one piece design? Any roof penetrations may need to be resealed. Don't use silicone. Dicor Lap Seal or 3m 4200 are good sealants. Water getting in anywhere along the length of the roof can run along the inside of a roof frame member and come out at the light.

 

[Smars00l]

Vic-
The ceiling liner is wet at the light housing spot, not discolored. I got on the roof and all of the screws look new and have the rubber washers between the roof. There’s no obvious pooling of water either. There’s a large crack in the sealant around the fan on the roof, and some of the sealant of the factory installed roof rack is peeling up as well. Hoping a reseal of this will fix the issue. We were in a wreck and our old camper was a total loss. So can’t afford for a whole roof on this guy. Thought we purchased a turn key rig.

 

[Vic Harder]

Vic-
The ceiling liner is wet at the light housing spot, not discolored. I got on the roof and all of the screws look new and have the rubber washers between the roof. There’s no obvious pooling of water either. There’s a large crack in the sealant around the fan on the roof, and some of the sealant of the factory installed roof rack is peeling up as well. Hoping a reseal of this will fix the issue. We were in a wreck and our old camper was a total loss. So can’t afford for a whole roof on this guy. Thought we purchased a turn key rig.

water leaks can certainly be discouraging! No need for a new roof! Take the time to remove all the existing screws, add a small dollop of sealant, and reseat (gently... the metal of the roof and supports is super thin). If you strip a hole, get one size bigger screw (#10).

I lay down a strip of butyl rubber under my roof rack rails, and also did 4200 for the screws that hold it down.

 

[Smars00l]

Thanks for the help Vic! Hopefully there will be a fry day here in Washington soon to take care of this quickly. Do you think all the screws should be removed? They seem brand new with that rubber washer.

 

[Vic Harder]

Thanks for the help Vic! Hopefully there will be a fry day here in Washington soon to take care of this quickly. Do you think all the screws should be removed? They seem brand new with that rubber washer.

Are they new? Tell us a bit more about your camper? Age? Where is the leaking light fixture? Driver's or Passenger side? You will notice that the lights are about 14" from the long edge of the camper. There is a ceiling "beam" that runs the length of the roof at that point that the screws holding on the roof (and roof rails too likely) penetrate from the top. Any water entering along that length can run along that "beam" (a 1" square aluminum tube) will run out any holes on the bottom of that tube, like the ones created by the screws that hold up the light from the inside.

Take off the light fixture and see if it will dry faster that way. Also check if the water flow/drip changes if you change the angle the camper is on (make water flow a different way inside the "beam").

Water can conceivably move all around the inside of the beams, so the leak may not be in this particular beam....

 

[ckent323]

I have long been suspicious that in conditions that support condensation, such as cold humid days and nights, that the hollow Aluminum tubes in the roof of the pop top can develop condensation that can run to the end of the tube or a hole and leak out. I have seen ice on the surface of the headliner that is over the roof tubing many times in our camper (we turn the heater down to around 45 deg at night but the thermostat is below counter level so the temps at the ceiling can get to freezing). I suppose the tubes in the wall could do the same thing and water could puddle at the bottom of the metal frame and perhaps leak into the floor box wood through attachment holes.

I have read of at least one person who relocated the thermostat up to the mattress level which might help mitigate the chances of freezing temps at the ceiling depending on outside temps but there is not much insulation in the camper ceiling (or walls) so if it is much below freezing outside it will probably be at or below freezing temps on the metal framing of the camper just due to the conduction of the metal.

I recall seeing someplace that in the newer campers (sometime post 2007) FWC started filling the Aluminum tubes with foam to mitigate condensation in the tubes and perhaps help add a little bit of insulation. I have not independently verified if this is true.

If you have roof racks chasing down leaks can be challenging. There are many screws into the roof tubing which could provide entry points for water, particularly at one end or the other where small puddles of water can form in the track slot behind the end caps. One approach is to remove all of the screws (or at least the suspected screws), clean the surfaces and holes with alcohol and then put a dab of 3M 4200 or equivalent on each screw before reinstalling them.

 

[Smars00l]

It’s a 2007 Granby. Yesterday I replaced all the hardware on the roof, new screws and put the sealant inside the screw holes before placing new hardware. There were a couple wet screws lifted from the end cap area of the roof rack so I’m hoping this was the culprit. Only time will tell.