Air Intrusion under siding at highway speed

[Monrow]

I've noticed a recent development that has me confused and concerned. When towing at highway speed, above 55, the siding at the left front of the trailer expands out up to 2". The expansion is easy to see in the driver's side mirror.
From the picture, the expanding area is in front of the window and up near the top. There were some small (pencil lead size) holes in the front trim silicon, so more silicon was added to seal. But no change after the added silicon.  Also checked was the window seal, basement seal, and the roof area and can find no place where air would be getting in behind the siding.

The problem seems to be primarily caused by headwinds - meaning, when traveling at highway speed with a stiff wind from the opposite side of the trailer (side wind from passenger side) there is no expansion, or only intermittent expansion... 

Thanks for any advice or direction.

2014 Jayco JayFlight Swift 26' Travel Trailer.

Monte

 

[Monrow]

Refresh..

 

[lynnmor]

For the siding to bulge out, it may not be attached properly.  I would pull off the trim corner and the siding, then you should see the problem.  Reinstall correctly.  It is not as bad as it sounds, but you should have a dry place to do the work.

 

[glen54737]

I had 1 that did this too. I put it down to pressure differential due to pulling through wind. I think if air was getting behind it it would tear off.

 

[Quillback 424]

It could simply be that air is getting into the RV and creating a pressure differential between the inside and outside. This extra pressure may be venting from the inside to out behind the panel that is bulging.

Before I pulled the outside skin off I would check inside behind the bulge area for wires entering the siding or other holes or access points where a positive pressure could be vented to the outside. Then, I would seal every hole, pipe or cable run going into the RV. Only then would I consider reworking the outside skin.

However, I'd find the problem before that outer skin rips off and creates a very expensive problem.

 

[Rene T]

It could simply be that air is getting into the RV and creating a pressure differential between the inside and outside. This extra pressure may be venting from the inside to out behind the panel that is bulging.

Before I pulled the outside skin off I would check inside behind the bulge area for wires entering the siding or other holes or access points where a positive pressure could be vented to the outside. Then, I would seal every hole, pipe or cable run going into the RV. Only then would I consider reworking the outside skin.

However, I'd find the problem before that outer skin rips off and creates a very expensive problem.

Maybe shutting the roof vents and close the range hood door and latch it shut if you can.

 

[Monrow]

Thanks for your replies

On the last pull home it did seem to be spreading, so it may be the siding separating due to not being attached properly. When it's happening it looks like the siding could pull off, it's like a balloon inflating...

We have some time before the next trip so will take your advice and check other areas to seal any air that may be getting into the rv. Up until now I was looking only around the area where the problem is. The roof vents and range hood are good suggestions too, thank you!

How is the siding attached? Is it simply put on like house siding, or is it glued to a backer board.

Many thanks,
Monte

 

[glockholiday]

Each layer of siding is attach to the one above and below it with clips, at least every foot. Some of those clip are broken is your problem. My trailer was fixed under warranty and I saw it while they had it apart and it didn't look like a job I wanted to do.

I've seen some older trailers that the bottom of one section of siding is stapled to the framework of the trailer and the top of that section is just wedged into a slot of the section above it.

My concern about the job wasn't the actual siding replacement but the sealing of the window and the front corner of my trailer.

 

[glockholiday]

Found a video, it's different than my 2007 with clips but you get the idea. https://www.youtube.com/watch?v=lkkjFYB9hV4

 

[lynnmor]

The video should be a great help to the OP.  He can see that the siding is not attached if it pulls away, and it will need to be pulled apart and done properly.  A cheap Harbor Freight stapler would really be an asset.

A mobile repairman might be an option if he doesn't want to tear it apart.

 

[Monrow]

Thanks for the video link and advice. will pull the siding down and reattach.