Installing Dual Pane Windows

[Lisa H.]

Hello all! I've been perplexed about how to go about the installation of my new dual pane windows for several reasons and just when I'm ready to dive in another issue arises. When I removed the old front window I noticed many spider cracks above and below the window frame on the exterior wall. In addition to this, as has been discussed in an earlier thread, the windows are 5/8" shorter in height than the hole from the old windows. Initially, I was going to fiberglass into the void and then recut a hole to size but now I'm questioning whether I should reinforce around the windows with plywood to help beef up the 1/8 wall that is now going to hold a much heavier window.

In reading some other posts I'm now wondering whether I should use one piece of plywood or put two "L" pieces together around the window. One author reinforcing a hole made for a hatch indicated that using "L" pieces and then fiberglassing them to the hull would still allow the hull to flex and would thus avoid creating more serious cracks in the fiberglass if it were not permitted to flex in stress conditions. Other folks appear to have epoxied a wooden frame to the fiberglass while still others simply sandwiched it between the window, the wall, and the ring. I'm sooo confused!!! My motto has always been, "If you do it right the first time you won't need to do it again." Given my MO, it's easy to understand why I research my projects so exhaustively and am then hesitant to begin for fear I'm going to make a mistake. Aside from my obvious neurosis , does anyone care to weigh in on this subject?

P.S.- In case you're wondering why I ordered dual paners, it's because I'm planning on insulating the cabin with a couple of layers of reflectix and vinyl. I have "lizard blood" and need all the help I can get to stay warm. I want my newly renovated trailer to be really nice and cozy when I'm done!

[Lisa H.]

Okay. . . now I'm beginning to worry that I shouldn't have gotten the dual pane windows since nobody has responded yet. How about framing the window with plywood, glassing it in, and glassing in furring strips from the lower corners to the floor to support the window? Would this allow the walls to flex enough? I'm concerned because one author indicated that if one made the wall too stiff more serious cracks in the fiberglass wall could develop. Plus, in addition to the front window I need to apply the same treatment to the two side windows.

[Donna D.]

The only current molded trailer manufacturer that I can think of that's installing dual pane windows as an option... is Escape. Ian and Paddy had their Escape 5th wheel retrofitted with dual pane windows. I bet Ian was there while it was done. You could always check with him/them to see what MAY have been done. Or maybe contact Escape directly .....

Ian Waymark profile

[Raya]

Just a note: You don't want to allow the walls to flex. Flexing fiberglass is prone to weakening and cracks and is always best avoided.

That said, what you also don't want to do is create a stress riser. That is, where you have a distinct line between a flexy area and a stiff area, which gives things a place to go awry.

I think many of the Compact type trailers did have wooden frames on the inside for the windows to screw into, didn't they? I wouldn't fasten the new windows to the fiberglass only, without some type of backing on the inside.

Glassing in stiffeners can be a good thing, but actually if you are running fasteners through the fiberglass and into your inner (wood or whatever) frames, you are already creating a sandwich, so I don't see any real advantage to fiberglassing those particular members in place. (By this I mean covering them with resin-saturated fiberglass cloth.)

How much do the new windows weigh compared to the old ones?

Granted, the new ones might be problematically heavy (I can't tell at this point), but also keep in mind that the windows (any windows) stiffen the shell considerably compared to having empty holes there.

If it is determined that you need stiffeners (stringers or etc.), then there are ways to add them while the walls are not yet covered.

Can you check into the weight difference?

Raya

[Lisa H.]

Thank you, Donna, for the tip on Ian and getting the ball rolling again. I just PM'd him. Hopefully he observed the installation and can offer me some insights.

Raya, the more I read your posts the more I wonder if you have a boat-building background? You've really got quite a knowledge base for this stuff and I'm glad you're out there sharing with us in cyberspace!

I'll weigh both the old and new windows tomorrow morning and get back to you with the data. My Trailswest Campster, although closer than a kissing cousin to the Compact, did not have a wooden frame under the window ring. The ring just screwed into the flange on the window and sandwiched the fiberglass wall in the middle. There weren't any holes drilled into the fiberglass at any point. However, it appears that the spider cracks may have been located directly above were the screws were.

On one of the side windows that I removed I noticed a lot of deeper spider cracks above the radius corners of the window. The side windows are even longer and heavier than the front window.

I met with the person who sold me the windows this afternoon and she does not have a problem with trading out the rings for ones that will accomodate thicker walls once I get the wall reinforcement tackled and can provide her with new measurements. That's a relief. But I need to get to that stage. Hopefully, I'll be in a better place tomorrow once I can provide you with the data. I really need to get this phase of the project done since I have several others that I need to complete before the trailer can be towed to the Lake Casitas Rally. Otherwise, I'll be tenting in a full hook-up site and that's not good!

[Raya]

Okay, I think I get the picture on your windows now. Those must have "clamp rings," whereas the ones I was thinking of from the Compact Jrs had an outside flange only and then you screwed (or bolted) through that and into a wooden frame on the inside (Trilliums were like that too).

Sounds like there were already some stress issues with the previous windows if you had cracks emanating from the corners (not necessarily purely from weight though). Some photos would be great (hint, hint).

Raya

[Larry&Carrie]

Yes, the Compacts had a wooden frame on the inside to catch the screws. Also the screws go thru the fiberglass. When I redid mine, didn't notice any stress cracks, even tho the factory 5/8 or 3/4 ply was rotten and falling apart.... Used 3/4 mahogany for frames on way back in, 'cause that's what we had. Larry

[Lisa H.]

I weighed and measured the old and new front windows and here are the results:

Old Hehr window weighs 13 lbs. and is 1.25" deep
The new dual pane window weighs 18 lbs. and is 1.75" deep

The weight of the new window is not so bad when you consider it has twice the glass.
(The photos were taken on the rug on the floor of the garage, not inside! Yuck!)
Below is a photo of the new front window . . .



Next is the edge measurement.



These are the cracks around the front window. . . I sanded the cracks down and was going to use Marinetex to fill them in.



This last shot shows the unsanded cracks on one of the side windows. These are actually the deepest of the lot. . .




Hopefully, this will give you a better idea of what I'm up against.

Thanks again for your advice in advance.

Is a in order? I think so! My newly resized photos actually posted!!! (congratulating self )

[Lisa H.]

I thought some photos that show the kind of ring that my dual panes use might prove useful as well.
I hope these clarify the setup specific to my windows.

This first picture shows the window and the ring.




This next picture shows the groove that the screws go into.
The flanges on both the window and the ring sandwich the wall in the middle.
The screws are not meant to penetrate the wall with this setup.




This last shot shows the space between the window flange and the ring flange where the wall will be. Unfortunately, the macro camera setting has distorted the measurement. The space is 5/16".




If the solution warrants getting another ring that has a larger gap to accommodate plywood or other wall reinforcement material, the window seller has kindly agreed to swap out the rings I have for ones that will work better. So I'm not limited by the space shown in the photo.

[Raya]

Lisa,

I've been thinking about your window installation, and I've got a few more questions, in the form of thoughts:

First of all, you're right in that the windows are not much heavier. Those corner cracks do extend into the fiberglass, I see, and not just the gelcoat, and they show some stress at the corners, caused by movement. So, you will want to address that with your new installation, since even the old windows caused those.

I've never seen dual-pane camper windows, but I know that with dual-pane house windows, there is often a seal so that there is a vacuum or sealed chamber between the panes. I've seen those fail and get cloudy due to movement in the house frame that broke the seal. So one questions is about whether there is such a seal to take into consideration on these windows? Do we have to worry even more about flex that we would with single-pane windows because of that? Maybe you could check with the manufacturer.

Another thought is that the force/weight of the windows will "pull outwards" on the walls as much as it will push downward. So it will be important to keep the walls "in column" and keep them from wanting to bow. To that end, does your Campster have a "bulkhead" wall like the Compact Jr. does? That is, a perpendicular wall about halfway down the side of the camper? If so, I'd be interested to know how securely that bulkhead is secured to the side walls. They would be very helpful in making the sidewalls rigid and less likely to "squash" (picture your camper a balloon, with a big hand pressing down on the top; with those bulkheads the walls resist bulging out much better as the hand presses down).

Then, I still don't totally understand how those clamp rings work. The side wall of the trailer must be "trapped" by the window frame, yet there are no holes in the fiberglass.... I guess I need a little more help visualizing. I'd love to see a section sketch.

My initial sense is that an additional framework adhered to the trailer walls around the windows would be adequate, along with the bulkheads, but I'm not feeling sure yet and would like to know more about the above.

Raya

[Lisa H.]

Hi Raya,
Thanks for getting back to me. I took some more pictures to better help illustrate the design of the Campster and the new windows.

The bulkheads are snug against the roof but only the kitchen side is attached to the roof.




There is additional roof support fiberglassed into the ceiling.




The window turned face down with the clamp ring on top.




Close-up of the window and ring.




Same as above with a book placed where the wall would be when the window is installed.




The hole on the clamp ring (resting on the window) for the screw to go through and attach to the window via the groove.




The groove on the window that the screw goes into.




It's doubtful that with the bulkhead support on the sides in addition to the reinforcement intergrated into the roof that the walls will flex out. The side windows amount to about 4 feet out of the six feet of wall beyond the bulkheads provided by the closet/refrigerator cabinet on one side and the kitchen on the other side. I would think that the windows would provide some kind of structural rigidity, but of course, I'm no expert. . . that's for sure. After looking at photos of Compact Jr.s and the like, I think the Campsters have more roof support due to the fact that the pop-top covers 5.5 out of a total of 9.25 feet of roof length, whereas the CJs pop-top goes across more than 90% of the length of the entire roof. Plus, the Campsters have integrated support fiberglassed into the ceiling, as you can see in the photo.

I am happy to report that I was finally able to locate some bearing rollers for the scissor pop-top lift mechanism after searching for a really long time. Although these rollers are not designed identically to the original rollers, they are going to work and the wheels are metal instead of that crumbly, cracking plastic. At least when I get the pop-top fixed and reattached, the old vent hole fiberglassed in, and the windows installed, I'll have enough work completed to go to the Lake Casitas Rally. I'll get there eventually.

Thanks for all your help and direction! I've been feeling a bit overwhelmed by this part of the project and am now confident that we will find a viable solution.

[Raya]

Hi Lisa,

You're getting pretty nimble with the photo posting! And good idea to put the book there - that did make it easier to see how they work. So the one thing I'm still not sure on, but I think I see, is that you have to have a really close tolerance hole in the camper (because the flange of the clamp ring has to "trap" the camper wall, right? And the flanges do not look at that wide); or am I not getting that right?

I agree with you that the bulkheads look like they are doing a good job. If they are tabbed in on one side, that is enough, IMO.

I guess if it were me, and since you have the inside of the camper down to bare fiberglass (or nearly so.. right?), here's what I would do. This may be based on faulty understanding of the windows still, so let me know if I have that wrong.

1) I think I would fiberglass (when I say that I mean with reinforcing cloth and resin, not just resin or just Marine Tex) the hole smaller, so that you have good, strong material for the clamp ring to "clutch." While I was at it, I would probably put a strip of glass all around the inside of the frame; that would help to stabilize those cracked corners (as I see the cracks do penetrate beneath the gelcoat.

2) Then, the decision is do you really need additional strengthening in the form of wood strips and/or a couple more layers of some structural type glass such as biaxial cloth? It's hard to say from here. I would probably make a decision as I went along and could really feel what was happening -- which is hard to do from afar.

If you do use the wood, I would at least "stick" it to the walls with thickened epoxy, or maybe construction adhesive (I'm more familiar with epoxy so I would probably use that), because you aren't going to have the screws holding it all together (like on the Compact Jr.)

On the other hand, if you glass in the opening, you might not need anything additional except the windows; again, hard to say from here.

3) Are you going to paint the outside of the trailer? If so, its hard to make those radiating cracks not come back through the paint, and you might have to address those further on the outside. You can try filling them with thickened epoxy fairing compound only, but then they do usually come back eventually.

If you're going to patch the gelcoat instead of painting, you may be okay as is, once you've added a bit of glass to the inside (if you do).

Have you decided what to use for wall insulation yet? If you reinforce the window opening with something thinner, like "just" fiberglass cloth, you might be able to run the insulation right under the window flanges; otherwise I guess you would either tuck it under the wood, or but it up against it, or...?

Too bad we're on opposite coasts; I'd love to see the Campster in person

Oh, and, what does anyone else think about this? I'm slightly working in the dark here, not having actually reached out and touched a Campster.

I hope this helps - I know it's filled with "maybe" and "perhaps" Sorry about that.

Raya

[Lisa H.]

Hi Raya,

Thanks for putting so much time and thought into your answers. I'll try to respond to your questions.

I see that you have to have a really close tolerance hole in the camper (because the flange of the clamp ring has to "trap" the camper wall, right? And the flanges do not look at that wide).

Yes, the tolerance hole in the camper as well as the size ring are important to this style of window. They had to make this clamp ring special because they usually do not install dual pane windows in trailers with walls this thin. That's why I mentioned that the seller is willing to get me other clamp rings if I need to make the wall around the window thicker.

I agree with you that the bulkheads look like they are doing a good job. If they are tabbed in on one side, that is enough, IMO.

I don't know what you mean by "tabbed." Could you explain this further, please? Do you see "tabs" in the photo of the ceiling?

. . . since you have the inside of the camper down to bare fiberglass (or nearly so.. right?).

The walls have a light coat of white paint and look and feel like orange peal surfacing commonly used in homes.

Then, the decision is do you really need additional strengthening in the form of wood strips and/or a couple more layers of some structural type glass such as biaxial cloth? It's hard to say from here. I would probably make a decision as I went along and could really feel what was happening -- which is hard to do from afar.

If you were here to "feel what was happening," specifically what would you be looking for?

Are you going to paint the outside of the trailer? If so, its hard to make those radiating cracks not come back through the paint, and you might have to address those further on the outside. You can try filling them with thickened epoxy fairing compound only, but then they do usually come back eventually.

I plan to paint the trailer next spring or summer with Interlux Perfection and do all the prep required by the manufacturer. Will filling the cracks with Marintex be enough for both now and later on when I paint the trailer? If I'm going to use a product like Perfection I sure don't want the cracks to come through the paint.

Have you decided what to use for wall insulation yet?

I bought an insulation material composed of a fiberglass cloth and mylar that's commonly used on the hoods of custom hot rod hoods to protect the paint. Additionally, I'm going to put a layer of Reflectix on top of this. Finally, I've got some nice white vinyl to allpy as the final layer. I've got dogs that shed and I need to be able to wipe down the walls easily and don't want a wall covering that hair will stick to.

Too bad we're on opposite coasts; I'd love to see the Campster in person.

Hey, didn't you say on another thread that your favorite mechanic is in San Diego? C'mon out any time. I'm certain you have plenty of other left coast fans that would like to meet you!

Oh, and, what does anyone else think about this? I'm slightly working in the dark here, not having actually reached out and touched a Campster.

More people responded to my question about ways to fill in the oversized window hole than this thread.

Yes, Raya, you have helped a lot. Thank you! Basically, I've really felt out of my element trying to figure out how to solve this problem using unfamiliar materials. I'm much more confident working with wood. I've watched nearly all of the Jametown videos and tried to read as much as I could about fiberglassing but have still felt somewhat intimidated mainly because I tend to be a perfectionist when it comes to building things. I appreciate fine craftsmanship and do not care for shoddy work. . . especially if it is my own work. Consequently, it's been kind of paralyzing not feeling confident enough to proceed. Unless my answers to your questions here have altered your analysis in some way, I think I'll just have to go for it!

Thank you so much!
Lisa

[Roger H]

Lisa, you're well into this... and I hate to be a wet blanket... but I have some reservations about your project.

I've had some significant cold-weather extended stays in fiberglass trailers, and I've had many, many fiberglass trailers over the years: some were single wall with single pane windows and a layer of inside insulation (four Scamps), some of them shell-in-shell (Burro & Uhaul) with and without insulation; both with single pane windows. And last, I've now had two Bigfoot trailers with heavy insulation and dual-pane windows (true four-seasons trailers).

Even the Burro, with fiberglass insulation between the shells with plexiglas single-pane windows stayed toasty-warm. My biggest heat leaks in it was the poor door seal.

Your Campster has canvas walls in the pop up. You can make that trailer twice as heavy with insulation, but you've still got canvas walls and a single-thickness roof in the top where all your heat escapes. That, to me, is an insurmountable problem if the goal is to stay toasty. I applaud your willingness to undertake the project, but I'll suggest that at the end you'll have an extremely well-insulated, double-pane windowed, (potentially) cold and drafty single-walled camper. I guess I'm just not convinced that the dual-pane windows and reflectix are going to accomplish what you're after in that particular trailer design.

I realize that you're in SoCal (lived there for many years m'self)... so I guess the question is how much camping are you planning to do where it's cold, and how "cold" is "cold" for you? And if staying "warm" while camping in "cold" weather is something you really want to do, is there something out there that will accomplish that more elegantly for you?

Roger

[Lisa H.]

Roger,

You bring up some very valid points about the insulation limitations inherent in Campsters. Please let me know what you think about this plan. (I hope I'm not on a fool's errand!)

I'm going to take apart the panel under the fiberglass pop-top and insulate it too. Then, when the weather reaches my "cold tolerance" (or intolerance, as the case may be), I'm going to lower the pop-top so the uninsulated boot will no longer be an issue.

The floor is another thing. . . I'm going to use a layer of the "hot-rod" insulation on the floor and then cover it with those foam tiles used in workshops. They're like 12 x12' ensolite tiles. Finally, I'll put the rolled vinyl flooring on top of that. By the time I'm done everything will be insulated except the door. As for the seals, well, I'm open to suggestions!

Thanks!
Lisa

[Bobbie Mayer]

I lower the pop top most nights- no worry about insulation there. I do notice that the windows collect moisture so assume they are pretty cold- but if I were really worried I think I'd put window quilts on them instead of worrying about dual pane windows- but then, I'm not as handy as you, Lisa! (I actually do plan to make window coverings that are insulated since my insulation is the furry part of velcro so I can stick them up with the hook part.)

Where I find the hottest is the uninsulated walls inside the cupboards and below the seats- I think doing those would be the first thing. Carpet over plywood for the floor itself seems fine.. but then, I rarely boondock and I just turn the heat on when its cold.

[Donna D.]

The floor is another thing. . . I'm going to use a layer of the "hot-rod" insulation on the floor and then cover it with those foam tiles used in workshops. They're like 12 x12' ensolite tiles. Finally, I'll put the rolled vinyl flooring on top of that. By the time I'm done everything will be insulated except the door. As for the seals, well, I'm open to suggestions!

Thanks!
Lisa

Instead of going through all that on the floor, why not just glue blue styrofoam to the underside of the floor? You can piece it like a puzzle to fit around all the frame and any plumbing. Seems to me that MAY be a better solution... stop the cold (or heat) before it hits the floor. Blue styrofoam doesn't attract moisture either.

[Judith Kennedy]

Hello all! I've been perplexed about how to go about the installation of my new dual pane windows for several reasons and just when I'm ready to dive in another issue arises. When I removed the old front window I noticed many spider cracks above and below the window frame on the exterior wall. In addition to this, as has been discussed in an earlier thread, the windows are 5/8" shorter in height than the hole from the old windows. Initially, I was going to fiberglass into the void and then recut a hole to size but now I'm questioning whether I should reinforce around the windows with plywood to help beef up the 1/8 wall that is now going to hold a much heavier window.

In reading some other posts I'm now wondering whether I should use one piece of plywood or put two "L" pieces together around the window. One author reinforcing a hole made for a hatch indicated that using "L" pieces and then fiberglassing them to the hull would still allow the hull to flex and would thus avoid creating more serious cracks in the fiberglass if it were not permitted to flex in stress conditions. Other folks appear to have epoxied a wooden frame to the fiberglass while still others simply sandwiched it between the window, the wall, and the ring. I'm sooo confused!!! My motto has always been, "If you do it right the first time you won't need to do it again." Given my MO, it's easy to understand why I research my projects so exhaustively and am then hesitant to begin for fear I'm going to make a mistake. Aside from my obvious neurosis , does anyone care to weigh in on this subject?

P.S.- In case you're wondering why I ordered dual paners, it's because I'm planning on insulating the cabin with a couple of layers of reflectix and vinyl. I have "lizard blood" and need all the help I can get to stay warm. I want my newly renovated trailer to be really nice and cozy when I'm done!