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How to seal roof A.C on trailer with corrigated metal roof?

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Im new to the forum, Hope this isn't a stupid question?

I just purchased this trailer last week, not even realizing that

the roof is not flat??? It's a 19 ft V nose trailer ( bought it new) in Dallas

The metal has a slight corrigation to it, not like a R panel or nothing, maybe

1/4 to 1/2" rise on the humps maybe 1" apart. I want to install a roof A.C. and have installed them on other trailers before but never on an uneven roof panel like this. Will there be any way to seal this? Will a standard seal gasket work or will i have to resort to another method? There is already a 14" vent opening, just need to add the bracing?

Any suggestion???

Thanks: Big D

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My trailer is fairly new (2008 Model) and the vent was already braced, so that was not an issue for me, you might want to see if yours is not already braced as well. As far as the corrigated roof, the A/C I installed had roughly a 2" thick piece of foam attached to the bottom (Carrier 13.5 BTU) and it sandwhich's to the interior unit. My roof was pretty flat but I would think a 1/4 gap would have been sealed by the foam after sandwhiching the interior and exterior units together. If not, I would use good quality UV rated outdoor caulk and apply it liberally to the gaps under the A/C until it is sealed.

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you can get plastic foam strips that are designed to go on corrigated roofs. They have the waves on one side with a flat side usually with some sort of sticky material to seal it off. Just put them on and caulk them up and you should be good to go. Try home depot or lowes. Btw, this is what we have to seal off the roof on our chicken house which has corrigated plastic roofing

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you can get plastic foam strips that are designed to go on corrigated roofs. They have the waves on one side with a flat side usually with some sort of sticky material to seal it off. Just put them on and caulk them up and you should be good to go. Try home depot or lowes. Btw, this is what we have to seal off the roof on our chicken house which has corrigated plastic roofing

I've never seen the plastic/foam type only wood. It is used (sounds like in your case) to raise the corrugate on one end to direct rain "run-off".

I would think the spay on foam would do the trick, just make sure to block it off so it doesn't spread and become too thin. If you can visualize that!

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I've never seen the plastic/foam type only wood. It is used (sounds like in your case) to raise the corrugate on one end to direct rain "run-off".

I would think the spay on foam would do the trick, just make sure to block it off so it doesn't spread and become too thin. If you can visualize that!

It's a foam used as a closure strip to prevent bugs and wind from blowing up under the raised portion of the tin. They make it to go under the tin (at the soffit), and over the tin but under the ridge cap (at the peak).

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Im new to the forum, Hope this isn't a stupid question?

I just purchased this trailer last week, not even realizing that

the roof is not flat??? It's a 19 ft V nose trailer ( bought it new) in Dallas

The metal has a slight corrigation to it, not like a R panel or nothing, maybe

1/4 to 1/2" rise on the humps maybe 1" apart. I want to install a roof A.C. and have installed them on other trailers before but never on an uneven roof panel like this. Will there be any way to seal this? Will a standard seal gasket work or will i have to resort to another method? There is already a 14" vent opening, just need to add the bracing?

Easy to do. Cut your 14" opening and frame it in with steel. In my case, I spread the weight (95 lbs) over 3 roof bows. Then add a second layer above the framed support which will lift the flange up or frame it with metal that is already taller then you roof bows. My roof bows was 1 1/2" thick, so maybe some 2" box tube. Then trim the metal and bend it over the inside of the opening after you cut it out, then with a rubber mallet, hammer the corrugation out of it so its flat where is fits over the framing. You could also just shim it with even strips of wood, and anchor it in place by screwing through the roof sheating just around the AC opening and through the wood and into the metal frame. Does this make sense? The foam seal on the AC will seal the screws too. Raising it slightly will keep the unit from setting low in a hole pulling in water. The AC unit will have a huge thick foam seal and it crushes when you tighten the AC unit down.

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Thanks for the info!!! I purchased a unit today, a friend is bringing it from Houston tommorow.My salesman said that the gasket seal will work, so Im gonna give it a go

Thanks again: Big D

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That does make sense, That would keep the air unit up enough that a pooling rain would not affect it. Thanks for your help!!!

Big D.....

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