Leak Finding: Northern Lite

Coveredwagon is the "expert" on leaks in a Northern Lite. I think he's had dozens and has pretty much taken the whole camper apart. You might want to ask for his input -- surprised he hasn't already commented on this thread.

on older NL's check around the 1. air con there a lot of flex on early units 2 also ck the refrige vent 3 last tank vent seals

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if you have access to a "heated "garage leave the camper out side over night / you'll need freezing temps /in the morning bring it inside if your lucky the areas where water has invades will show up as condensation on the outside where the frozen water is !from in the wall and may be you can track the visible condisation back to the source of the leak good luck !!

The Northern Lite (and Bigfoot) top clamshell overlaps the bottom, so it will not leak even if not sealed or fastened. They are haphazardly sealed, and fastened with many sheet metal screws. The trim has no sealing function at all, it merely hides the screw heads from view. There is no problem glassing it over, it isn't done by the factory because of cost. It will also be difficult to make look very good.

The pressure test is the best way to track an obscure leak. Close all the doors and windows, devise a means to pressurize (slightly!) the interior with a large shop vac outlet or a leaf blower. The spray a bubbly substance like Windex on the suspected leaking areas. One of the complications to this is finding all of the big holes left underneath or in cabinetry, these need to be stuffed with something at least temporarily if they leak too much pressure away. If you are successful in getting it pressurized, you are likely to find many small leaks that aren't yet leaking visibly water inside.

Reddog1 wrote:
It may look tacky, but if you put white duct tap from just above the overlap covering the overlap molding, that might shield it from leaking. If it does, you will have found the problem.

Photos of the TC would be helpful.

I did this as well when I was leak searching. I taped off different areas eliminating them one at a time. If you are in no hurry this method works well.

I've done some similar leak searching as you with you Northern Lite. I've learned that the water can travel a great distance before showing up because of the center seam. I had water leaking out of a rear bottom drain hole in the belly of the camper coming all the way from the front top cabover window.

I would suggest an air pressure leak test to really help your search. I did the DIY version of this with leaf blowers and learned a lot. The results were immediate. It showed the exact spot of the window leak where the butyl tape didn't seal properly.

Since then I am carefully removing all windows and re-doing those as well and every single other hole cut through the entire camper. Slow process but makes me feel better actually knowing the sealant is as it should be.

I agree with Reddog 1 that the chance that the center seam is leaking is low but it can happen. There are a lot of screws (ie holes) for the water to choose if the center seam is the issue. If it is coming in that way removing the screws one at a time and applying sealant and then re-installing will solve that. While you're at it replace them with stainless screws. If the screws are sealed that takes care of the center seam. The way the seam overlaps the screw holes are the only way in for the water.

Good luck. It is frustrating dealing with these leaks. I have had people come up to me saying I have a Northern Lite, great no leaks. I just smile and don't get into it with them. Anything you cut a bunch of holes through will leak eventually no matter what. Especially in the province we live in.

It may look tacky, but if you put white duct tap from just above the overlap covering the overlap molding, that might shield it from leaking. If it does, you will have found the problem.

Photos of the TC would be helpful.

Hi,

I resealed the window with butyl tape, as you describe.

I'm quite certain the main leak is not coming from the window -- I have sprayed colored dye (lots of it...) so that it ran down the clamshell (avoiding the window) and using a white paper towel I was able to confirm the drops coming through were definitely colored.

That said, this other new leak up front might be window related..

I really question the leak being at the clamshell joint. It is possible the water is wicking through the screws, but I really doubt it.

This is a cutaway of the clamshell overlap on a Northern Lite.




Although this is doable ; "... I'd consider completely removing all the clamshell trim (white metal and black rubber) and glassing (or epoxying) a seam across the two halves, forever sealing the unit.", I don't think this would solve your problem. I think you have a cabover side window caulk leak, possibly marker light or some other caulk failure.

I have a 1988 Bigfoot which is the same overall construction. I woke one rainy morning to find a pool of water under the matress. When I got home, I pulled the passenger side window, and discovered the window was not caulked properly. over twenty years before it leaked.




A couple of side photos of your TC would help us help you find the leak.

Wayne

EDIT: The butyl tape is what should be used on your windows, with no other caulking.




Tape squeezed out before trim with plastic knife


Excess being trimed

I can't say for certain about the Northern Lite brand, but most molded fiberglass units like that (Scamp, Casita, etc.) join the halves with more fiberglass. They glass over the seam, and the resulting joint becomes even stronger than the rest of the shell. That said, I have seen pictures of some Trillium trailer seams that were inadequately glassed over and were leaking.

What did you use to reseal the window? Silicone is to be avoided, because when it fails it leaves a film that new silicone will not adhere to. The film (often invisible) must be removed thoroughly (a combination of acetone and abrasion) from all surfaces before new sealant is applied, and the best sealant for that application is butyl tape.