Window Resealing on Collins short bus

[Briana]

Hey there! This is our first ever post cuz we've finally come to a problem that no one else on here seems to have solved (at least not to our satisfaction). We hope this will help someone else out in the future too!

So we bought a 2003 Chevy 3500 Express Collins body short bus (6-window w/ handicap door) back in March and we've slowly been demoing it over the past couple months. The weather is finally clear enough that we feel ready to start thinking about resealing the windows, but we're running into a few issues. We'd ideally love to take them all out, clean them up real well and remove all the gunk in the frames on the bus, then reseal them better than before.

However, we realized today that our bus windows are made differently than the majority of other makes/models and it seems to be a Collins-specific thing. The windows are currently sealed with fairly thick rubber tubing which is peeling out of the bottoms of some of them to reveal a gap at least a 1/3" thick. There's also rubber tubing coming out of the tops of some of them too, leaving another large gap at the top of the window when the rubber tubing is removed.

We actually reached out to Collins today to ask if they could replace all the rubber tubing for us upon a recommendation from a friend, but they don't make those style windows anymore so they couldn't help us out. The guy we emailed said, "I recommend placing foam towards the inside of the window at the bottom and filling in with caulking on the outside. The foam will act as a dam not allowing the caulking to come inside the bus and stay under the window."

We're not sure that's such a good idea because we haven't heard great things about foam as a moisture barrier in skoolie windows.

So we're wondering if anyone else has dealt with removing, resealing, and re-inserting windows in a Collins body bus or successfully filled in those significant gaps with anything other than the rubber or foam (like a lot of butyl tape or many layers of caulking)? We only ask because we've heard that foam and weather stripping actually tends to catch and hold water rather than repel it and we really don't want to make our windows leak more after we go through the whole process of resealing them.

Any suggestions/advice you have would be helpful! We've attached a few pics for reference. Thanks in advance!

Photos are of the gap under the seal while the window is still in; a crowbar fitting through the gap of a different window; and what it looks like when we removed the window where the rubber is peeling.

[peakbus]

I don't have a Collins but it seems most buses have a lot of sealant around windows and most find they leak. The foam he suggested is not the sealant, the caulk is. The foam is called "backer rod" in construction, and can be purchased at home improvement stores. It is inserted so that the caulk doesn't have to fill the whole gap. When caulking has to span a large gap, it fails due to expansion and contraction. Usually there would be something at the back of the gap for the backer rod to seat against. Perhaps you could fabricate something to close the gap before sealing.

[Simplicity]

Hmmm, I can't really see how the windows fit into their space, but it sure looks like they don't just pop out and back in like mine do.

I understand your desire to get in and clean things, then put them back together all new and neat. Yet, sometimes, if it ain't broke, don't fix it.

I have two suggestions:

1) For the windows you have not yet removed, get some good stiff and small detailing tools to clean them up for appearance sake. Then, remove as much of the sealant and such that is currently exposed on the outside and reseal.

Water is not a problem if it can't get in.

2) For those windows you have, or have to, remove, I'd do all the detailing, then I'd use something like this:

https://www.amazon.com/Neoprene-Weat.../dp/B0758JKKQV

It's not a simple foam, it's neoprene. Get one that has a high density to it, that will fill just a bit more of the gap between the skin of the bus and the window. This isn't to waterproof, it's more to fill the gap and seat the window.

Then, seal the window from the outside. It's the outside sealing that will keep the water out, not the inside foam.

Per the butyl tape, it's not really made to fill large gaps. I've used it on my travel trailer and tried it in a couple of my bus windows. I'm switching back to the neoprene foam, which was what was in their before, and sealing the outside.

Hope this helps.

[DeMac]

Do not use silicone or neoprene to seal around windows. Both retain moisture.

As Peakbus stated, use 'closed cell backer rod' and urethane base sealants (not adheasives). Butyl tape all face joints. Sikaflex 221 or 227 the exterior seam. Verify that your glazing does not leak.

[Briana]

Thank you all for your comments and suggestions, they're all very helpful!

We're debating right now about whether we need to remove the windows we want to keep (6 out of the 10), but since most of them are leaking and the foam/rubber that's currently in them is coming out and leaving large gaps in at least half the windows, plus the level of rust that we've found on the sills, we feel like we really should take them all out and try to rust-treat and reseal them properly.

DeMac, have you worked with the Sika closed cell backer rod before? The only product I've found so far is 3/4" thickness, which is about twice as thick we we'd need. Do you have any idea if they sell 1/4" or would you recommend another similar product that might come in a smaller width? Like, would something off-brand like this work?

I just watched a little tutorial about the 3/4" Sika closed cell backer rod & Sikaflex (here) and am wondering if we find a product that fits our window gap (1/4" on top and bottom) and then do something like this if it sounds like it will work (or just be more hassle than it's worth):

1) Remove window
2) Clean window and remove all existing tubing/caulking/etc.
3) Clean & rust treat window hole and remove all existing tubing/caulking/etc.
4) Re-insert window, screw in (it's only held in by two screws, one on each side of the window)
5) Slide in closed cell backer rod on top and bottom gap of window
6) Apply Sikaflex sealant all around the backer rod where it touches the window frame and bus frame
7) Let dry and have perfectly sealed windows!

My biggest question is about when and where to put the backer rod...does it make more sense to try to attach it to the window before re-inserting the window into the frame? Or do you think it'd be easy enough to slide it into the gap once the window is already set?

Thanks again!

[Simplicity]

Originally Posted by DeMac

Do not use silicone or neoprene to seal around windows. Both retain moisture.

As Peakbus stated, use 'closed cell backer rod' and urethane base sealants (not adheasives). Butyl tape all face joints. Sikaflex 221 or 227 the exterior seam. Verify that your glazing does not leak.

Hmmm, not totally in agreement with "not" using neoprene high density foam. It says waterproof pretty boldly for this particular brand.

https://www.amazon.com/Density-Water...ybrkr=81e5aedb

It also comes in a large variety of sizes.

Per the Sika, great product...but it's not just a sealant (at least the 221 / 227), it's also an adhesive. If you have to take the windows out for any reason, have fun.

Our school district uses the neoprene foam and regular silicone sealant on the outside. It works great.

[DeMac]

DeMac, have you worked with the Sika closed cell backer rod before? The only product I've found so far is 3/4" thickness, which is about twice as thick we we'd need. Do you have any idea if they sell 1/4" or would you recommend another similar product that might come in a smaller width? Like, would something off-brand like this work?

I just watched a little tutorial about the 3/4" Sika closed cell backer rod & Sikaflex (here) and am wondering if we find a product that fits our window gap (1/4" on top and bottom) and then do something like this if it sounds like it will work (or just be more hassle than it's worth):

1) Remove window
2) Clean window and remove all existing tubing/caulking/etc.
3) Clean & rust treat window hole and remove all existing tubing/caulking/etc.
4) Re-insert window, screw in (it's only held in by two screws, one on each side of the window)
5) Slide in closed cell backer rod on top and bottom gap of window
6) Apply Sikaflex sealant all around the backer rod where it touches the window frame and bus frame
7) Let dry and have perfectly sealed windows!

My biggest question is about when and where to put the backer rod...does it make more sense to try to attach it to the window before re-inserting the window into the frame? Or do you think it'd be easy enough to slide it into the gap once the window is already set?

Thanks again!
‐--------------------------

Yes. I have used closed cell backer rod on a variety of applications, including my home & RVs. It is used in expansion gaps around metal commercial windows (AL & FE), concrete underground manhole boxes, basement joints, parking garages....

We removed the windows and cleaned all the old butyl first. Only two wimdows at a time.

We put 1-1/2" ccbr into the hollow track above each window. We pushed it up there before inserting the windows, except the e-windows. They have their own recess above where we put the ccbr into the frame, on those.

Sika sells it, but not in many sizes. Any brand is probably fine. Make sure it is all closed cell, not a mix. Some use both, then apply a 'skin' to the rod. 50 cent per foot is avg.

For smaller gaps, use a roller tool normally used for inserting 'splines' into the frames of window screens.

The Sika 227 should be applied after replacing the window. Only the exterior, bottom egde. Up the sides, if you must. It is removable and uv resistant. As stated in the manufactures product description.

We used butyl tape around the bus framing, then pressed the window into the bed of butyl. Once you do one or two, you will learn the finesse. Be prepared to do one or two twice. Before we added Sika to the outside, using only butyl, we hose tested and achieved leak free seals. Once you feel the windows are good, seal the outside lip.

On the inside, roll 1/8" or 1/4" backer rod into any interior gaps, then color calk over & smooth. This should upgrade your rain tight windows, to air tight windows.

Air tight (convection) is not often mentioned here. Yet, it is a primary factor in condensation. Have you ever left the fridge or cooler ajar? Beads of water appear in the crevice, moisture even when there's no rain. That is the front, where high pressure meets low pressure. Same happens around leaky doors and windows.

[Briana]

Okay cool, I think we’ve got our plan down now!

Just need to pick up the screen roller tool, butyl tape and CCBR today.

Quick questions:

What’s the best type of butyl tape to use for aluminum windows with steel frames (if there are different types of tape)?

And:

Will this product be okay to use as our sealant instead of the Silka? We just bought two tubes of that stuff (Loctite PL S30 Polyurethane Roof and Flashing Sealant) cuz it’s what we’re planning on using to patch the holes in our metal floor and we figured it’d be fine for sealing the outside of the windows too. Any opinions about using that stuff instead of the Silkaflex? And could we use the Loctite PL sealant for inside and outside or should we find a different type of caulk for interior use instead? Thanks in advance!

[zen builder]

I see this thread is a couple weeks old, and if you still need advice, go to Youtube and search "Navigation Nowhere" . I think the guys name is Daniel , not sure. Anyway,he has a 5 window Collins that he is doing, and in one of his posts , he removed the windows , resealed and reinstalled.