Guaranteed to leak... tongue frame to front sill

[chilly81]

Sadly, my couple hour job of redoing the corner putty on my trailer turned into fixing a rotted corner. Luckily it's fairly limited to the front sill (the 2x3" sitting on the frame), and I've been able to jack things up and just replace that sill (instead of gutting the interior).

The problem is likely mostly do to leaks at the corner molding which I've fixed.

Unfortunately I see a secondary problem that I am looking for solutions.

There is really nothing preventing water pooling on the 'vee' of the tongue of the trailer frame from wicking back into the sill. I think that was the most rotten area, and think this was a contributor. There is literally just a tarp like material between the frame and the wood/trailer. I'm thinking of just caulking the heck out of that area to preven water from flowing back along that trailer frame rail into the sill area.

Anyway, just wondering if this is a common problem with travel trailer designs. Mine is a 2002' Nash 22H for what it's worth.

[chilly81]

That water seal idea sounds like it might be a good one. I have already put things back together though. I may be able to try something similar with some eternabond from the diamond plate to the frame. It would be maybe 1.5" of soft/unsupported/tarp in the middle, with at least an inch of contact on the bottom of the diamond plate and the front of the trailer frame. Not sure how it would hold up. I'll take a look at it.

lol westend - yes I did patch up the panel and replace the fiberglass insulation. Again, luckily it's under the bed (that is the water tank you see) and in a drawer - so I didn't have to worry about it looking pretty. Just some screws and some gorilla tape to cover any gaps between the patch and original paneling, and it's air tight again.

[hddecker]

Good practice not to leave stuff closed when the rig is in storage and put some sort of humidity control in the rig.

[westend]

Nice work!
Yes, you're lucky not to have to remove cabinets and interior paneling. I bet it gets pretty darn cool in that one drawer in the Winter. Also, isn't that a corner of a fresh water tank I see in the one pic? I guess it makes no difference if you only use the Nash in the Summer but I took great pains to make sure everything is insulated and heated air can go through those spaces. I don't leave any cabinet doors open and such when camping when temps are low.

[hddecker]

Being as you have the camper tore down, if you can get a gap between the frame and the floor to slide a piece of Ice & Water Shield then fold it up over the front. Water shield is the rubberized membrane that goes down under the roofing shingles.

The only problem is the roll size, I think the smallest roll is 4' X 36'.

[chilly81]

Wrace wrote:
The kick-out molding that runs across the bottom and appears to be fastened to the thin panel. Is that only fastened to the thin panel or is it also secured to the front-to-back stringers somehow?

It's bolted through to the sill. There's actually a strip of plywood, somewhat shorter than the sill, stapled to the face of the sill. The bottom corner of that plywood strip is what the paneling butts up against. Then the kick out molding is lag bolted through all that into the sill. With the angles involved, a table saw and drill press would make it pretty easy - a little finicky and sloppy with my jigsaw and hand drill... but should hold together fine.

Wrace wrote:

- When the diamond plate is in place does it ride up on the ledge of the kick-out molding?

Yes the diamond plate has a bend at the bottom that wraps around that kick out molding. It it bolted from underneath and the top lip of the diamond plate tucks under the upper siding.

Wrace wrote:

- What type of fasteners are those used to secure the new sill?

There are 4 heavy vertical machine bolts bolting the sill to the frame. I replaced the 2 exposed ones on my end with SS versions in the same locations. The sill was just stapled (big staples) to the joists and plywood above. I just used some big long 2.5"+ beefy screws (the heads you see in the pics).

Wrace wrote:

- You mentioned a rotted corner likely caused by leaking corner molding. Was this just a failure of the caulking on the corner molding?

Yes, the putty degraded and had obvious gaps. So I was just planning on replacing the putty on all 4 corners. This was my last one, and grew in scope a bit. Overall, I think reasonably lucky that things weren't worse.

[Wrace]

Thanks for posting the pictures. That's a good example of catching something relatively early and getting it fixed, thus prolonging the trailer life.

Some follow up questions if you don't mind.

- The kick-out molding that runs across the bottom and appears to be fastened to the thin panel. Is that only fastened to the thin panel or is it also secured to the front-to-back stringers somehow?

- When the diamond plate is in place does it ride up on the ledge of the kick-out molding?

- What type of fasteners are those used to secure the new sill?

- You mentioned a rotted corner likely caused by leaking corner molding. Was this just a failure of the caulking on the corner molding?

Thanks

[chilly81]

Here's a pic I took, having removed the worst of the rotten wood (including 1/2 of the front sill). I circled the area where the rot was the worst... around a big bolt through the sill and trailer frame - right near that A frame section. You can see the tarp material that just gets pulled up and stapled, then the diamond plate goes over it. 3" back from that sill and the floor joists are perfectly clean - so it was all coming in from that front edge.



Then a pic with that sill section replaced - ready to put back together.

[Wrace]

Thanks for posting on this subject. I have a 97 22H and I'll take a look at that area tomorrow. My 97 doesn't have the diamond plate across the front like the newer models, it just has a black vinyl cover that is fastened with snaps. I'm the original owner and that cover has never been off the trailer. Guess maybe I'll take it off and have a look.

[chilly81]

Ah, Brulaz, I think you're right - on my older trailer, the top surface of the A part of the frame is level with the main box. They must have figured out the drawbacks of that configuration (as I'm doing now) and adjusted the design.

I think I need to at least put some type of dam on the top of the A frame to prevent the worst of the water from migrating in... that was the worst of my rot - some at the corner, but worse right where the leg of the a-frame intersects the main box.

Then the secondary effect is a little harder - similar to how @westend is describing - there's about 1/2" gap between the bottom of the diamond plate and the top of the frame across the whole width of the trailer. It's not totally exposed, but it's only protected by this woven tarp material. Between road spray and dripping water clinging around the bottom corner of the diamond plate (no drip edge), it's going to wick water right in. I considered spraying a waterproof expanding foam inside the small volume behind that tarp material to tighten it up and solidfy it - then maybe run a bead of caulk between the trailer frame in the tarp. Seems kind of messy, but I think it could work.

[westend]

Brulaz,
My Starcraft is built just like your depicted frame. The siding laps the front metal plate and behind that is the start of the wood frame. There is about 3/4" of exposed wood that can and will soak up any water from below. Yes, the siding and metal plate should carry most of the water away but the wood is exposed and I know what will happen there, eventually. There are also the cutouts in the siding where the A frame intersects the siding.

I think what I'll do is install an aluminum trim piece to cover the exposed wood. I have a siding brake so it's about a 10 minute operation. Small aluminum trim is also sold at the big box stores so an off-the-shelf solution is probably available, also.

[brulaz]

A lot of trailers have the "A" part of the frame mounted completely below the main metal box frame. Northwood's frame has it built into the metal box, but the recent pictures I've seen still show it an inch or two below the top of the metal box frame.

So I don't see how water can drain from the "A" to a wood floor mounted on top of the metal box frame.

Maybe on older Northwood frames the top of the "A" was flush with the top of the metal box frame?

[westend]

Thanks for posting!
Just walked out and took a look at mine. I have a piece of trim rail that runs the length of the front, cut out for the frame rails but directly behind that there is an edge of the wood frame exposed. I'll have to seal that up like you are doing. I think you've exposed another weakness in trailer construction, never thought to look until you posted. Thanks!