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000brunswick · 06-13-2020, 06:16 AM

I've posted prior to this with respect to a major reno I'm performing on my TT. I'm about to close up the back-end interior after a lengthy roof repair, and completely replacing the back wall. With the ceiling exposed inside I notice something a little odd. I have what appear to be 3 identical roof vents. One is definitely for the plumbing as I can see the stack exposed inside from the reno. The other 2, 1 at the front, and another near the back, are from what I can tell..... for show lol. They don't vent anywhere. There is no hole in the roof at their position. They're just attached to the exterior of the roof, and for the life of me I cannot figure out why. On a home we have roof caps to vent the space between the roof substrate and the insulation. Should these vents be actually vented??

van-gogh · 06-13-2020, 06:55 AM

Quote:

Originally Posted by 000brunswick

I've posted prior to this with respect to a major reno I'm performing on my TT. I'm about to close up the back-end interior after a lengthy roof repair, and completely replacing the back wall. With the ceiling exposed inside I notice something a little odd. I have what appear to be 3 identical roof vents. One is definitely for the plumbing as I can see the stack exposed inside from the reno. The other 2, 1 at the front, and another near the back, are from what I can tell..... for show lol. They don't vent anywhere. There is no hole in the roof at their position. They're just attached to the exterior of the roof, and for the life of me I cannot figure out why. On a home we have roof caps to vent the space between the roof substrate and the insulation. Should these vents be actually vented??

The roof vent is not just to help the odor, but to keep the water flow as low as possible. If you took a straw and put into water and caped the top with your thumb you hold in water and STOP FLOW. The only water meant to stand in a pipe is sinks, toilets, washing machines, etc. But for anyone who has any ordo inside your RV should use a cyclone plumping vent to extract all ordo while driving or dead stop. The outside pass wind will put the ordo out. I hope all of this is helpful. JUST DON'T CAP them.

bddadles · 06-13-2020, 07:02 AM

I understand the vents with no pipe on them but are you sure the others do not have a hole through the roof? I would expect attic vents (don't have a better name for them) above the ceiling and through the roof.

Spk64 · 06-13-2020, 07:08 AM

Some pictures would help. Sometimes there are holes added in roofs for prep on other options, Solar, satellite etc.
What are the holes capped with on the outside?

000brunswick · 06-13-2020, 07:09 AM

Yes I totally understand plumbing vents. But these other 2 vents aren't anywhere near any plumbing. They are attached to the roof but seemingly have no purpose. I'm wondering if I should be at the last drilling out a home underneath them to vent the "attic" space if you will.

000brunswick · 06-13-2020, 07:13 AM

Here's a pic. The vent circled in red is the plumbing. The two in green go nowhere

bneukam · 06-13-2020, 09:10 AM

Manufacturers did start installing these so called attic vents a few years ago. Units with trusses and batten insulation have had moisture trapped and mold issues.
They don’t use any vapor barrier, so water vapor can easily enter this space.
If you haven’t had any issues to this point I am not so sure I would cut holes in the roof. Venting requires air in, and air out, so installing these is really a joke. Personally I like manufacturers that laminate their roof with the use of foam board, which eliminates this issue.

000brunswick · 06-13-2020, 12:31 PM

Quote:

Originally Posted by bneukam

Manufacturers did start installing these so called attic vents a few years ago. Units with trusses and batten insulation have had moisture trapped and mold issues.
They don’t use any vapor barrier, so water vapor can easily enter this space.
If you haven’t had any issues to this point I am not so sure I would cut holes in the roof. Venting requires air in, and air out, so installing these is really a joke. Personally I like manufacturers that laminate their roof with the use of foam board, which eliminates this issue.

Yes I agree. In talking with some friends with TT's most have a laminated roof. Mine however does have this "attic space". There are 2 vents. One at either end. Sooooo in a way there would be airflow would there not? I'm a little perplexed with the subject. I've put a lot of man hours, and money into this reno so the possibility of the roof rotting after putting it back together is not something I'm interested in.

St8-e · 06-13-2020, 01:31 PM

This is an interesting thread...I was kind of under the impression that these roof vents were coming from each of my tanks (2 grey, 1 black). I put Camco cyclone vents on all of them and it now makes me wonder if I, pointlessly, put a cyclone vent on an “attic” vent...

bneukam · 06-13-2020, 11:02 PM

The attic vents will reach just under the roof sheathing, so it should be easy to see.

Personally I don’t think they do much, but I guess it wouldn’t hurt to go ahead and cut them out.

Cold weather camping is when the water vapor will escape through this attic space. Being mindful of how much water vapor your creating will be most helpful, not these vents. If you don’t cold weather camp then I wouldn’t worry about it. It’s the warm moist air that rises to escape to the colder drier air. Just like a house needs adequate venting, and proper vapor barrier. The greater temperature difference, the greater the draw.

000brunswick · 06-14-2020, 07:30 PM

I pulled the roof and front cap off today and I can say that the vent at the front was not vented at all. With respect to cold weather camping I guess it depends on what your consider cold lol. We're in South Eastern Ontario and camp until the end of September sooooo it gets chilly. We use the furnace I'll put it that way. I'll likely just use a hole saw and vent them both. I'm definitely putting some screen over the hole before attaching the vent cap again though. The front cap had a nice wasps nest in it. Not a fan. Thank you to everyone for their input. This site is very helpful. I'm hoping to be done the reno by the beginning of July. I'll likely stay a new thread and either link to pictures, or I'll make multiple posts and walk through all the steps we took. I've been taking quite a few pictures along the way.