Ventilation in extra small Teardrop

[mreidsma]

Hello! I'm building a *really* small Teardrop for use in my backyard (2' wide by 6' long, no galley). I'm making it primarily from things laying around the shop or wood the carpet place down the street throws out. I'm building in a single door on one side, with a fixed 25" square window from the ReStore opposite. I have some Lexan I was going to use for the door window, but I'm also trying to make sure I have enough ventilation in case I have the door closed, especially since the big window won't open.

I'm thinking an 18" x 24" window in the door (or smaller), and I could add another 8x10 to the "foot" end, but because of my extra small interior space a Wiley window won't work. Will top hinges with some sort of drip channel and/or gasket keep weather out? Anyone ever build a plexiglass sliding window like they use in Deer blinds? I don't have to worry about water tightness at highway speeds (or any speed, really. The "trailer" is 2 pneumatic casters with wheelbarrow style handles on the opposite end).

Would it be better to also add some soffit-style vents to the side, so I don't have to rely on windows to get ventilation? I have a bunch of these, the same that I've seen in some homeless shelter designs, but I don't know how much air will flow through them.

Thanks for any advice you might have!

-Matthew

[tony.latham]

Hello! I'm building a *really* small Teardrop for use in my backyard (2' wide by 6' long, no galley). I'm making it primarily from things laying around the shop or wood the carpet place down the street throws out. I'm building in a single door on one side, with a fixed 25" square window from the ReStore opposite. I have some Lexan I was going to use for the door window, but I'm also trying to make sure I have enough ventilation in case I have the door closed, especially since the big window won't open.

I'm thinking an 18" x 24" window in the door (or smaller), and I could add another 8x10 to the "foot" end, but because of my extra small interior space a Wiley window won't work. Will top hinges with some sort of drip channel and/or gasket keep weather out? Anyone ever build a plexiglass sliding window like they use in Deer blinds? I don't have to worry about water tightness at highway speeds (or any speed, really. The "trailer" is 2 pneumatic casters with wheelbarrow style handles on the opposite end).

Would it be better to also add some soffit-style vents to the side, so I don't have to rely on windows to get ventilation? I have a bunch of these, the same that I've seen in some homeless shelter designs, but I don't know how much air will flow through them.

Thanks for any advice you might have!

-Matthew

Matthew:

I think you need to plan on having a fan. We had a 4x10' teardrop for several years. It had a computer fan in it and I added a second one. They weren't enough. (I've read that there are computer fans that should push enought CFM but I don't know from experience.) It was a big deal, with our new 'drop to have a 12V Fantasic fan with a reversable switch. I think even if you have two big windows, the heat is going to build up along with the humidity. Since you'll have access to an extension cord, it shouldn't be much of a challenge.

T

[48Rob]

Matthew,

Soffit vents are a good idea, it is easy to fall asleep and "forget" something as simple as cracking a window.

I'm with Tony on the adequete ventilation issue.
Some parts of the year just a cracked open window will do, but other times it could get very steamy inside just from your breathing in the enclosed space.

I like the wheelbarrow handles idea, good thinking!

Rob

[skyl4rk]

A vent near the ceiling and an opening in the floor seems to work well to draw fresh air in without a fan.

[mreidsma]

Thanks for all the advice. I also emailed Paul Elkins of elkinsdiy.com, as he has built a few shelters of roughly the same footprint without fans. He gave me some good advice on vent placement (down low near your head as you sleep, he recommends) as seen in his latest Airstream-style bicycle camper. I did notice on his bicycle camper page he mentions wanting to install a fan, though.

I think after Rob and Tony's advice, I have a plan: I'll use 4-6 passive round 3" soffit vents to start, but run wiring for a fan to two of the vent locations. If the soffits don't cut it on their own, I'll swap two out with small fans (possibly enlarging the hole if needed). I did a lot of work on my attic last year, getting ventilation in, and the numbers seem to say that the passive vents will work. However, you can't breathe numbers! I'd rather be prepared and comfortable than scientifically correct.

I'll let you know how the ventilation turns out, and thanks again for the advice.

-Matthew

[48Rob]

Matthew,

It is good to have a plan!

I just completed a 4600 sq' building that I designed.
I chose to use passive ventilation, but also installed a powered backup system.
So far the passive works very well.
There is an (operational) cupola up high which draws air from vents located down low in the building.
It works so well that I've had to push the employees who smoke farther than 30' from the building as the smoke is drawn in by the system...

On my camping trailer, I have passive and active.
We put a 3" hole in the floor with a computer fan (nice enclosure, metal grill) and of course we have a roof vent, and it has a fan also.
The lower vent with fan off, along with the upper vent, fan off, brings plenty of fresh air into the trailer.
On pleasant days, it helps to cool the trailer by venting the hot upper air.
On warm days with the fans running it will keep it comfortable.
On hot days we use the air conditioner.

Rob

[Shadow Catcher]

We have a large teardrop 6X10 and it has two Antec 80mm Tricool (three speed) fans in the opening of a Fantastic fan along with two windows.
each of them will move 100CFM on high and we seldom have them set at more than low or middle speed.

[deleted]

Hi Matthew,

My 4'x6' trailer has two Soffit vents located higher (above) the two side windows. It was a detail my builder insisted on. They're good so that I don't accidentally asphyxiate myself but they provide very little relief when it comes to air flow or circulation.

That said I did't realize how essential it was to have two windows on opposite walls to create a pleasant draft through the cabin when the ceiling fan is turned on in warm or hot weather. With no windows open it gets stuffy quickly. With the vent fan blowing out and one window open it's better. But with both windows open it's comfortable.

Surprisingly (to me) the time the ceiling fan/vent has been most important is in inclement weather (rain/cold) to release the humidity created inside the trailer. I rarely have had a problem with condensation as long as both windows are cracked or the vent/fan is on. On very hot days it helps to keep the door open as well along with the windows and the vent/fan blowing out.

[mreidsma]

Staci,

Thanks for the feedback! I had been starting to lean towards adding a fan now rather than waiting, and hearing your experience definitely makes the case. Your trailer is much closer in size to mine (although I could fit two of mine in yours! Eek!) so I suspect I'll get even toastier. But the humidity thing, especially in inclement weather, was something I hadn't considered. And I'm right down the road from you, so I'll get the same kind of weather you've experienced. I'd rather have a way to get that humid air out.

My current thinking is to add a few soffit vents (but not the 4 or 6 I had initially planned), a ceiling or wall-mounted fan, and build the door window to open up. I'm also considering adding a few small (11x14) windows in the "galley" end, under my storage shelf, that would also swing open and help with cross-ventilation. Since my 4yo daughter has claimed that end as "hers," she'd enjoy the view, too.

I had decided to build a sort of "fake" tongue box (since I am not building on a trailer). The box will have access like yours, from the inside, and will now house the DC setup in a sealed (but vented) compartment along with room to put shoes and boots when I get in. I realized that if rain or snow hits (which, let's be honest, is 60% of the time here in Michigan), I wouldn't want to haul my shoes up into the nice clean cabin, nor would I want to leave them outside. So the fake tongue box will give me a place to stash shoes while keeping them out of the weather. Now, after seeing your setup, I think I can put my DC setup there as well, instead of taking up valuable space on my storage shelf.

I also saw that your round soffit vents have both an inside and an outside cover. The package I have (left over from a project around the house) are just for outside, so I think I'll replace them with the kind you have, which it seems have insect screens and will look much nicer installed. What kind of material is your interior wall covering made of? It looks like it holds up well!

-Matthew

[deleted]

Hi Matthew,

I ran into the possible humidity problem in Wisconsin, California, Oregon, South Dakota, Iowa, Montana it happens anytime it's cooler outside than inside the trailer.

So cute your daughter has claimed her space

I think you'll love the interior tongue box access. I have no regrets about doing mine that way.

My interior wall is made of 1/8" birch plywood that is painted. It does hold up well. When it gets dirty I've been able to clean it. But, it does have one small, shallow dent in it from something banging against it. I didn't realize it is kind of soft (I guess because it's so thin) so now that I know I use care not to let things hit it hard enough to leave a mark.

[pchast]

I'd suggest you consider adding a couple of small floor level vents too. They can be opened or covered as needed.

[mreidsma]

Pete, that's good advice. Current thinking is to have a floor level vent near the back, with ceiling level vents at the front. In the middle, near the ceiling, I'll have the fan, like in this quick sketch:

ImageUploadedByTapatalk1424284248.361143.jpg (94.95 KiB) Viewed 1990 times

I think the combination of passive and powered vents will be enough even when I don't have the windows open. But if not, I can always crack a few windows!

-Matthew