Air Movement

[cdnred]

We bought a new to us 4x8 teardrop that had no roof vent. The side doors have sliding windows that allow for some air movement by cross ventilation. After buying this teardrop I realized the importance of having a roof vent whether it was powered or not for air movement..

I inquired at my local RV shop on the cost of having a roof vent installed. They told me that without knowing what or where the cross members and electrical runs where that they'd need to remove the inner ceiling panel. They gave me a rough estimate of 6 hours labor for the install coming close to $1000 at the high end. The same cost would apply if I chose to go with side wall vents..

I haven't actually used this teardrop yet since I've been working to upgrade it for shore power and paint it so I can't tell on what conditions I can expect. I had thought about leaving the side windows cracked and using a small fan to help circulate the air. Reading about roof vents here that others have commented on, it seems to be much needed for comfort..

Do any others have any simple solutions for improving air movement in my case..? I'd love to add a roof vent but see it as maybe becoming a major problem to get installed..

[cdnred]

Looking from the inside, the previous owner had installed a screened opening to the rear hatch area. It maybe simpler to install a powered vent in the rear hatch cover to minimize the rework needed to install in the roof. Thoughts.?

[Tom&Shelly]

On our first trip east from dry New Mexico, I was surprised one morning, in Ohio, to see the dew condensed on our walls where I had not hogged out the 3/4 inch plywood core and added foam. Not sure how that would work with an aluminum roof, but it might be a way to see where the cross members are. You might also try a stud finder from the interior. Some good ones might even be able to tell where the wire runs are.

Another thing to consider: The first teardrops (in the 30's and 40's) didn't have roof vents. Instead, they had vents on the walls near the roofs with louvered metal plates to keep the rain out. I wouldn't do that--I'd at least have something that would close, but computer fans there might be an alternative to consider.

Just some ideas. Hope they might help!

Tom

[Tom&Shelly]

Looking from the inside, the previous owner had installed a screened opening to the rear hatch area. It maybe simpler to install a powered vent in the rear hatch cover to minimize the rework needed to install in the roof. Thoughts.?

Possibly a very good idea. Perhaps the original builder/owner kept the hatch open at night to improve circulation? Honestly, I think you need to camp in it once or twice and see how it works as is.

Tom

[MickinOz]

The first teardrops (in the 30's and 40's) didn't have roof vents. Instead, they had vents on the walls near the roofs with louvered metal plates to keep the rain out. I wouldn't do that--I'd at least have something that would close, but computer fans there might be an alternative to consider.

Just some ideas. Hope they might help!

Tom

I did the vents in the side walls, One down at head level, one up as high as I could go, further back in the cabin, on each side wall. 4 vents in total. I installed butterfly vent covers on the inside so I can close them off, and louvred vents on the outside.
Never had rain come in, though that isn''t a major feat when you consider that if we get 12 inches of rain for the whole year we've done well.
One recent trip in the rain, the cross flow/convection wasn't enough to deal with the exhaled moisture of two of us sleeping in the cabin.
So I have installed a computer fan under one of the butterfly vents. Still a work in progress (it's a bit noisier than I'd like), but last trip it most definitely kept the cabin dry.
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[Pmullen503]

+1 on venting through the side walls or under the hatch. I'd hate to cut a hole in an intact roof.

[cdnred]

I was surprised one morning, in Ohio, to see the dew condensed on our walls where I had not hogged out the 3/4 inch plywood core and added foam. Not sure how that would work with an aluminum roof, but it might be a way to see where the cross members are. You might also try a stud finder from the interior. Some good ones might even be able to tell where the wire runs are.

Tom

Good method for finding where the cross members might be located, thanks..

Honestly, I think you need to camp in it once or twice and see how it works as is.

Tom

I agree it's best to try it out for a few days or trips to see if there's really a need for it. Was just reading a few posts about venting and planning ahead on what's needed to further update the tear. I'd really rather stay away from modifying the roof if possible. We're not much for cold weather camping and at my age (73) I've begun to favor the hot weather more..

[tony.latham]

I bought my first teardrop from Hunter. It was a little 4 x 8' without a ceiling fan.



The doors had two screened windows. It had two 4" louvers in the galley walls and a computer fan in the bulkhead. Without the louvers, there was no way the fan could move air.

It wasn't enough. I added a second computer fan in the bulkhead. It still wasn't enough.

I wish I had an answer, but I can tell you this: when we got a tour of a 5'-wide with a ceiling fan, I was making sawdust three weeks later.

Tony

[working on it]

...Another thing to consider: The first teardrops (in the 30's and 40's) didn't have roof vents. Instead, they had vents on the walls near the roofs with louvered metal plates to keep the rain out. I wouldn't do that--I'd at least have something that would close, but computer fans there might be an alternative to consider....

Here are three posts on other threads where I show my rain-proof side vents that I use in four positions on my 4x8 trailer:

• 1)https://www.tnttt.com/viewtopic.php?f=2&t=73669&hilit=+wall+vents#p1275943,
  
  
• 2) https://www.tnttt.com/viewtopic.php?f=42&t=73684&hilit=+side+vents#p1276214%20,%20 and
  
  
• 3)https://www.tnttt.com/viewtopic.php?f=2&t=75355&hilit=+side+vents#p1297575

The front two vents have 12vdc computer case fans (mounted on piano hinges) that enable me to use them to suck air in/blow air out (they're reversible) or swing away from the vents and aim them towards the inside.

There are two vents in the galley/storage area walls:

• 1) one ended-up just becoming a lift-up cover for the A/C exhaust duct (it required unimpeded airflow, and there's a 240 cfm axial fan used inside the ducting https://www.tnttt.com/viewtopic.php?f=21&t=54945&hilit=duct+fan&start=15#p1014620), and
  
  
• 2) on the other side, the vent admits ambient air to cool the A/C chassis (there's a 110vac computer case fan moving the air thru the chassis).

[tony.latham]

where I show my rain-proof side vents...

Out of curiosity, why didn't you install a ceiling vent fan?

Tony

[working on it]

where I show my rain-proof side vents...

Out of curiosity, why didn't you install a ceiling vent fan?

Tony

Several reasons:

• 1) My wife's business trailer (20ft Puma) had (a) a ceiling vent cover (plastic) break, and also (b) a leak around the cover. I was looking for a metal covered vent when I found the type I chose to side-mount, instead.
  
  
• 2) I was in shipping/receiving at the time, and saw the vents I was choosing on many semi-trailers every day, some on their roof, and some on the front wall; neither placement site showed signs of water leaks.
  
  
• 3) My trailer roof already had over a dozen holes in it already (though sealed with PL adhesive and silo paint, with clear acrylic laquer over that), so I decided not to cut a BIG hole up there.
  
  
• 4) I was initially after an automotive/industrial look for my squareback, and those big, ugly, galvanized vents were just right, IMHO.
  
  
• 5) I had thought I'd be going offroad at some point (never did), and wanted my vents "armored" as not to be broken by limbs or branches (I was fabricating hard window covers to protect the side glass, but never added them), so those vents were surely sturdy enough to withstand contact.
  
  
• 6) Since those vents are proven rain-proof, I'd never have to close them ever at camp, unlike an overhead vent fan (my wife's vent had a "rain-proof" add-on cover, which didn't work). My vents don't leak.

[cdnred]

The doors had two screened windows. It had two 4" louvers in the galley walls and a computer fan in the bulkhead. Without the louvers, there was no way the fan could move air.

It wasn't enough. I added a second computer fan in the bulkhead. It still wasn't enough.

I wish I had an answer, but I can tell you this: when we got a tour of a 5'-wide with a ceiling fan, I was making sawdust three weeks later.

Tony

Good points.
My next tear will definitely have a roof vent already installed. The best spot would be directly overhead in the cabin but without knowing the location of the framing makes it a costly venture with having to take the interior headliner down. I'll take another look at how the headliner was installed to see if I can't find a simple solution to drop it on my own. I was debating placing it in the rear hatch cover but that would make it difficult for opening and closing as needed. I'm not much in favor of side vents, preferring to have them on top..

[tony.latham]

The best spot would be directly overhead in the cabin but without knowing the location of the framing makes it a costly venture ...

I think it was Tom who said there are some stud finders that will show you where they are, and I'm sure he's right. And I don't think they're the $10 ones that find drywall nails.

If you could find a 14"-wide spot, I think it would be possible to make the cut and insert framing from inside the hole.

Tony

[cdnred]

I think it was Tom who said there are some stud finders that will show you where they are, and I'm sure he's right. And I don't think they're the $10 ones that find drywall nails.

If you could find a 14"-wide spot, I think it would be possible to make the cut and insert framing from inside the hole.

Tony

I've got one but not sure if it'll be accurate enough for what I want, if not I'll check out HomeDepot next week and see what I can find.

Thanks for the help..
Helmuth

[rjgimp]

+1 on venting through the side walls or under the hatch. I'd hate to cut a hole in an intact roof.

Yep. +2