Sealing Side Windows

[Scott]

Hey Guys,

I decided to re-seal the large driver’s side coach window in my 1994 Premier, and I’ve run into some interesting tests of patience. The factory seals were foam weather stripping (LOL), which at some point must have leaked as evidenced by the gobs of acrylic caulk that the original owner put all around the seal flange. I couldn’t stand to look at it any longer, so I removed the window, and cleaned up the opening and window flange. I placed one layer of butyl putty (3/4” wide by 1/8” thick) on the window flange, and reinstalled the window. Now, I never checked the window opening for flatness, but I’m fairly sure the fiberglass shell curves toward the top (not an even taper, but rather a curve). I say this because the gap between the window flange and the shell is quite a bit larger at the top than it is at the bottom. So the 1/8” thick putty didn’t get compressed at the top and is not sealed, while the bottom flange is nice and snug with just a little putty bulging out, which is what I was hoping for all the way around.

Soooo, I’m guessing that I’m going to have to double up on the butyl putty tape to compensate for the curved window opening. Two 1/8” layers, and hope for the best. Has anybody else had to do this to achieve a seal? It seems less than ideal…

Thanks,
Scott

[Blue~Go]

Were you able to see what's in the walls of your rig around the windows? I have a Chinook wall construction drawing from 1999 (of the passenger side, but driver's side looks similar) and there is a square section comprised of two layers of 1/2" plywood (placed back-to-back for 1" total) that runs all around the windows. For example, on the passenger side, the piece is 38" tall and 75" long. I'm sure 1" of plywood can take some curve, but it must not be much? My windows fit flush all the way around.

I see yours is a Premier, presumably with the rectangular (vs. parallelogram) windows. If so, I wonder if the forward/upper corner extends further forward (into the place where the Concourse window slants back and therefore doesn't go?). I can see that my rig's walls curve in up there (and you can see the plywood in the Concourse is cut away there). OTOH, maybe your windows don't go any further forward than the top corner of the Concourse ones (although my guess would be they split the difference?) Here is the drawing for reference:

wall construction detail.pdf

(666.95 KiB) Downloaded 524 times

Sometimes on a fiberglass shell (boat cabin, RV wall) the frame of an added thing is actually "used" to straighten the fiberglass some (this is bad if overdone, but a little bit is common). Places I have found that on my Chinook are the refrigerator lower vent opening and the water heater door/frame opening. With those items removed, a slight curve is assumed. When they are put in place and tightened up, it becomes flat (we are talking about very slight changes). In some cases this was because Chinook's original "side pieces" (1/2" plywood strips bonded to the edges of the opening with what looks like bondo-like polyester filler) had either bent or de-bonded from the shell slightly (1/2" ply is not that rigid).

So anyway, I'm wondering if, when you had your window out, you could see if there was the 1" plywood surround. I wonder if you can tell if the window was "pulled tight" (presuming clamp ring windows here), and may originally have held things flat (certainly most windows "want" to be flat). Could some fastener or wood have changed due to water incursion or rot? Then the shell was "allowed" to curve?

Can you post some photos? I'm just thinking out loud here, based on things I've seen over the years, but I can't see yours. In general, "padding" an area with caulk or bedding compound is not a great idea, but then I can't see what the other factors are. You obviously also don't want to bend the window, nor straighten the shell to the point of cracking, but I can't see if either is happening or may happen (maybe you can).

BG

[Scott]

Thanks for the thoughts...

I’m pretty sure my window opening doesn’t have plywood. It looked like normal 1” thick lumber slightly resin-bonded into the shell, and plastic inserts at the corner radii. There was some water staining, but no rot. I should have inspected the bare opening more closely and checked the window flange for flatness. Then I’d know more about what’s going on. The gap difference from top to bottom is about 1/8”, maybe less. If the window was helping the shell take a straighter profile, I’d be pretty surprised and mildly disappointed, but what you’re suggesting seems possible considering the enormous size of the opening. The factory weather stripping was probably 1/4” thick, so maybe they were compensating for a natural curve in the geometry of the shell. I’m gonna pull the window out again this weekend if weather permits, and I’ll shoot some pics. I’m going to try the double layer of putty and be more careful about the screw installation sequence in the clamp ring.

If you’re a hobbyist looking for a never-ending project, it turns out that an RV is a pretty good solution!

[Blue~Go]

1” thick lumber slightly resin-bonded into the shell, and plastic inserts at the corner radii.

I could "see" that. Maybe the plywood on the Concourse was used because it's easier than building a parallelogram out of wooden framing pieces (or rather, since the parallelogram windows came first, and the Premier came later -- they changed to the "stick frame" for the rectangular windows of the Concourse).

I should have inspected the bare opening more closely and checked the window flange for flatness. Then I’d know more about what’s going on.

I've gotten to the point where I just always take a jillion digital photos of anything I might want to see later. But of course there is always the time I don't....

I’d be pretty surprised and mildly disappointed, but what you’re suggesting seems possible considering the enormous size of the opening.

I'm not saying our rigs are built like the finest boat (they, after all, have to sustain piles of waves hitting them), but I will say it's rather common for this to occur in various brands of molded fiberglass RV's that I've seen. Fiberglass seems hard, but actually it is floppy in large sheets. Sometimes the windows and other "frames" that are put in do actually do some of the stiffening (like I bet the sides of our rigs would be somewhat floppy without the windows in place, which I think become somewhat structural). Not floppy like they would fall over, but floppy as in they would assume some curve (i.e. bulge outward slightly at the "waist").

I removed the lower refrigerator vent (went to a compressor fridge) planning to put solid fiberglass there. I elected to use a pre-made piece of flat fiberglass board, then plan(ed) to tab it in place with fiberglass tape from the inside. Bye-bye leak potential. Lo and behold..... there were gaps at the corners. I had to fabricate a pulling method to "pull" the rig up straight in order to get the patch piece on a flat plane (the vent was probably doing something similar). Not that it's going to turn into the shape of a pumpkin or anything, but as you have seen, just 1/8" or so out of flat plane is a bummer.

I’m gonna pull the window out again this weekend if weather permits, and I’ll shoot some pics. I’m going to try the double layer of putty and be more careful about the screw installation sequence in the clamp ring.

Sounds like a good plan. Otherwise you'd be forever plagued by it (although of course how aggravating to have to remove it again, but, correct move I think).

If you’re a hobbyist looking for a never-ending project, it turns out that an RV is a pretty good solution!

Or a boat, house, airplane....

[Blue~Go]

Lookie what I found in my "various guts" photos. The photo quality is horrible, but it shows the driver's side window-frame construction of a Premier in progress! This is likely circa 1997 or so.

This looks like it reflects what you saw. If so, I can easily see it bulging out a bit at the "equator," and the window frame needing to "suck it in." Reason I say that is two-fold:

1) Looks like 1x pine lumber laid flat. That is not super resistant to bending in the direction that would cause your bulge (bulge in middle, so top of window lies away from shell).

2) It may have been bonded to the shell with the same bondo-like putty that bonded the strips around the edges of various rectangular openings on my Concourse (utility doors, refrigerator vent frame, etc.). It had failed on many of those (the putty bond, I mean). Polyester has poor secondary bonding characteristics, and who knows how good the prep was.

I *think* the window frame would be fine to withstand this sort of minor "suck in." Maybe if you look at the shape of the extrusion you can be a better judge of that. I've certainly seen it in the past on other windows. On the other hand, if you felt you needed to, you could get in there an re-bond the wood, use something stronger, etc. But that would be a big project, and I'm guessing that the window frame would do the job (especially presuming the wood isn't rotted, so you have something to "clamp against" (presuming you have clamp-ring style windows... do you?).

BG

PS: Not to say you should take a short-cut, as those often come back to haunt, but.... if you can tell the wood is not rotten, and the windows are clamp ring, and you do have enough butyl in there if the window goes flat...... and you feel the window extrusion is strong.... you might be able to "suck it in" with the fasteners now that you know what you are up against. (Of course what you would actually be doing is sucking the shell out flat to the window.) If you have anything super heavy in the upper cabinets over the couch, you might remove it. Probably not contributing at all (and who would put anything THAT heavy up there), but no need to have anything extra pressing downward (helping "equator" of shell to bulge out). Of course you also want to go slow/easy/distributed as you don't want to put a point load on one spot if you do try this.

[Scott]

After I got home last night, I took a closer look from the front of the rig, and it looks like the shell curves inward ever so slightly at the very top of the window opening. This results in a larger gap along the top edge, precisely where I don’t want it. Fooey. It was getting dark, so I may have been seeing things. Anyway, the window flange looks evenly gapped along all the other edges. I’m just going to pull the window out and double up the putty along the top and hope it’s good. I’ll know more Saturday. Thanks again for all of your input, Blue. Coming from a residential construction background, I’m still trying to get my head around the possibility that a window could be structural, but I guess it makes sense considering the size of the opening and the design of the rig.

[Blue~Go]

I hear you. On a house you rough in openings, and have headers and the opening is rock solid. Then you put in a window, and it more or less floats on a few shims and you nail it down, but the house is JUST the same, frame-wise, whether or not the window is there.

And it's not that the windows are quite structural on our rigs, but they do play a part. The rig won't fall down without them and yet they do impart a certain rigidity and... maybe you could say "influence the shape." Many times a frame will "tell" an opening to be straight/flat/what have you. This is just how it goes with relatively floppy, low-tech fiberglass layups. And for the most part it seems to work just fine. Still takes some getting used to

[Scott]

An elaborate update for anyone who has interest…

I’ll start by saying that this is my first RV, and I’m still familiarizing myself with its unique systems, construction, and design strategies. I’ve done a lot of residential construction, a lot of automotive repair, I was a machinist for a decade, and I’m currently an engineer (i.e. I just push a mouse around and try to look busy). So I’m usually “fairly” confident when assessing situations and repairing things.

Now that I’ve told you how awesome I am LOL, I’ll also share that this window has humbled me, big time, which is embarrassing to say because it’s just a dang window. I had to explain to my girlfriend why I was sitting in my rig late Saturday night crying into my beer. Definitely a low point. Part of my troubles arose from my own bad decisions, but also a slightly shoddy factory installation, and an ill-fitting clamp ring. And I was working alone, and I was trying to deal with intermittent rain.

1) The window has two adjacent grooves running the along the inside of the frame. The holes that receive the screws that secure the window with the clamp ring are drilled into the outer groove at what seem like randomly spaced locations. In some cases, however, a few holes were drilled into the inner groove. Well, using the inner groove is a great failure because the screws gradually bottom out on a tapered part of the window frame and prevent the lock ring from tightening down, and if you’re really smart, you keep tightening the screw until the head breaks off of the cheap 18-8 stainless screws you bought. So I had to remove a couple broken screws, re-drill a few holes in the correct window groove, and make sure the clamp ring matched up. Disappointing that this was considered an acceptable installation from the factory.

2) The cross section of the window opening from the outside in goes like this: fiberglass shell roughly 1/8” thick, then 1/8” plywood, then 3/4” thick standard lumber strip, then 1/8” plywood for the finished interior panel. The outer plywood and 3/4 lumber are attached to the fiberglass shell with what appears to be poly resin and a little bit of fiberglass. The thickness of the window opening ranged from 1.120” to 1.220”. I know what you’re thinking, .100” variation sounds like nothing. But it was enough to prevent the clamp ring from doing its job when it bottomed out on the window flange in the narrower areas before compressing the 1/8” thick putty. And there wasn’t any rot.

3) The opening had zero vertical clearance for the window in the center of the opening, so when dry-fitting everything, I had to wedge the window in and use a disconcerting amount of force. Even then, it still would hang up along the top before getting the flange to lay flat against the shell. Horizontally, the opening had 1/8” clearance per side. Tight fit. I found the high spots in the shell and took them down a little with a rasp. Easy 20 minute job. Then the window dropped in perfectly flat against the shell without force. I won’t blame Chinook for this poor fitment since I’m sure the shell has settled and moved around a bit, and this is an enormous opening. BTW, the cabinet lends a ton of rigidity in the area above the window.

As I mentioned in an earlier post, the shell has a very slight curve at the top of the opening, but it turns out that wasn’t my problem. Once the real issues were discovered and fixed, everything sealed up nicely with one layer of 1/8” thick putty.

To summarize, I had a lot of trouble with this window. It’s all good now.

[Blue~Go]

Scott,

How great to read that you prevailed! And especially that it was because you figured out why things weren't right and so were able to correct them. So much better than just piling on more sealant in that corner. Go you!

And oh boy, could I ever identify with your "crying in your beer" episode description. I have been reduced to the same (only remove beer and add cursing) by quite a few Chinook/RV/boat projects. It's miserable.

IMO even the "good" RV's (of which I would say Chinook is one) are still built with quite a few compromises. That just seems to be the way the industry rolls. Things are slightly better in boating; but then people are willing to pay more for boats in the first place (in some cases anyway), and it's normal for them to last 25, 50, or 100 years with numerous (expensive) refits, regular surveys (at which defects are pointed out and corrected as boats are often expected to measure up to ABYC guidelines - though not all do), and etc. And still there is plenty to cry and curse over. Been there, done that

Non-leaking, properly bedded window. Yeah!!!

[Riste]

I just found this string. I have a similar situation where the mounting screws for the trim piece on the driver side window penetrated into the channel where the opening part of the window slides. As the (hopefully) attached picture shows the water runs forward and got to the plywood and it rotted. Not a big deal to repair the wood but how to stop the water might be. It looks like the sliding part of the window does not seal completely and on a forward slope water wants in.
Suggestions?