let's talk about ventelation

[rustytoolss]

So I've been thinking about my future Foamie build. And was planning to in stall a RV roof mount crank up vent (with/or with out a fan). But then I got thinking ,instead of cutting a big hole in the roof (potential leak). What would be the harm of installing a few small non closing (always open/with screens) vents at the upper edge of the walls, and some at the floor level. By having them at the top and bottom you should has a good flowing system. That would always be moving air. Or would this cause unwanted moisture in the cabin of the camper ?

[Tomterrific]

I feel a roof vent is the best to get air flowing. You will not have any problem with leaks as there is a metal flange with plenty of screw holes. I used Mortite brand rope caulk, which is an easy to use non hardening caulk, between the flange and roof. Mortite handles like modeling clay. I used finish washers under the screw heads to widen the load on the sheet metal flange. A tip is to fill the under side of the finish washer with a ball of caulk, this caulk is forced against the screw and excess is forced out the sides for an absolute seal around each screw.

I made a post about a giant roof vent that would be almost the entire width of the roof. I've given some more thought to this and it seems easy enough. One can't have too much ventilation.

I also feel open windows and doors are the best for the sides. A breeze is needed and/or a roof vent will draft up to pull air through the windows. I wish I had more roof vent rather than the single vent I have now which is why I'm dreaming of multiple and larger vents. You may want to plan dutch doors if you are making your own doors. Dutch doors are as easy as cutting a door in half and hinging the top and bottom. Swinging open the top let's in air but keeps the bottom private.


T

[TimC]

Another option, not necessarily the best, but, I like how it came out. You can see how I dealt with the ventilation topic in my build journal on page 5...

viewtopic.php?f=50&t=63575&start=60

It was fairly complicated to accomplish, but, I have no chance of roof leaks and with two quiet 44cfm case fans I have plenty of air movement as long as my windows are open. There is a "duct" space above the cabin cabinets and that is closed off in the back of the cabinets. Of course I had to add a couple vents on the hatch walls to allow for air movement. The hatch is very air tight and would stop all air movement when closed. Looking back I think I would put in higher cfm fans and vent them down through the floor, maybe through the wiring raceway.

[tony.latham]

We had a factory-built teardrop that had screened windows on the doors and a 4" computer fan that vented into the galley. The galley had two always-open vents.

That computer fan even with the windows all the way open frequently wasn't enough. (There's higher volume computer fans out there these days.)

But... our current 'drop has a Fantastic fan in it and it's a big deal. We always have it cracked open a couple of inches at night along with our Vintage door windows up about 4". When needed, we turn the fan on for a bit and it's amazing. (If you install it correctly it shouldn't be a source for leaks.) I don't think you can build a passive system that will work for you 100% of the time. Teardrops are tiny little cabins for two.

Me? I'll stick to that top of the ceiling vent fan. There's a reason the industry puts them there.

Tony

[GPW]

Either you want basic ventilation ( breathing ) , or you want air conditioning (cooling) ....

[bonnie]

I would like both


Sent from my iPhone using Tapatalk

[S. Heisley]

I have 4 small low windows where the bottom of the windows is at about 3.5' and one large window where the bottom of the window is at about 5'. That system works pretty well most of the time. When it gets up into the 90's and beyond, I use an O2Cool fan to help. I also have a non-fan ceiling vent but find that I haven't used it in the past 4 summers. If I had it to do over, I would not put a vent on the roof. If I did, I'd put it on one of the side walls, near the top of the wall. (If you're building a foamie, you can make this decision later.)

In parts of the Midwest, you can still camp until the snow flies and maybe even after that, if it's not too much snow. So, depending on where you are, you may want to have something that you can close up when it gets down around freezing at night or it may be too drafty. Even then, you'll still want one window or something open a tad, though, to help keep condensation down.

[rustytoolss]

Either you want basic ventilation ( breathing ) , or you want air conditioning (cooling) ....

Well I'm thinking of moisture buildup and ventelation.

[TimC]

Another option, not necessarily the best, but, I like how it came out. You can see how I dealt with the ventilation topic in my build journal on page 5...

viewtopic.php?f=50&t=63575&start=60

It was fairly complicated to accomplish, but, I have no chance of roof leaks and with two quiet 44cfm case fans I have plenty of air movement as long as my windows are open. There is a "duct" space above the cabin cabinets and that is closed off in the back of the cabinets. Of course I had to add a couple vents on the hatch walls to allow for air movement. The hatch is very air tight and would stop all air movement when closed. Looking back I think I would put in higher cfm fans and vent them down through the floor, maybe through the wiring raceway.

I should qualify my statement that 88 cfm (2*44) is "plenty of air movement...". Ventilation (air changes) is completely different than cooling, and, ventilation was my primary concern. At 88cfm my air completely changes about every four or five minutes. I guess if you camp more in the "off-season" like I have been doing ventilation is the more important consideration. I live on the WI/MI border and do most of my camping in my area or north of here. It is rare to have night-time temps much above 70 degrees. Even the last two weeks with temps in the mid to upper 80s it cools to the 60s most nights. I feel that most of the folks on here don't experience those conditions much, so, take my suggestion that 88 cfm is sufficient with a grain of salt. Tony is correct, you will likely need/want more movement.

I designed my vents to allow for when I may be away from the TD and it begins to rain my Wiley windows and fans can be open and operating without fear that wind/rain will soak my sleeping quarters.