With Wave heaters and I am guessing more efficient propane/electric refrigerators, do I need to recreate this vent at all? Will the wall vents suffice for any new appliance? I cannot see exactly where it runs, but I gather the small round vent towards the back, which I've not removed, is for the toilette.
Only other vent is for the plumbing, it runs between the sink and shower, and runs up the back of the now empty cabinet. I cut out a whole for this when I installed the ceiling. As I guess this vent is for grey water only would I still need to vent to the outside? If so, can I install a less substantial round vent just for the grey water pipe? That is back to my original question, with the wall vents and more efficient appliances, do I need a roof vent here at all or can I go with something smaller... or should I just recreate the vent I had? newceilingtop by Tom Myers, on Flickr
They were like that. All in pretty good shape so I was able to re-use. A bit of rot on a couple where they were toe-nailed, but I went with screws this time, through curbing down to frame, and then curbing into rafters. Seemed to lock things down sufficiently. I think I will still raise any vent framing, but I've not seen the arc on others' ceilings so hoping that helps some with run-off.
Post by John Palmer on Dec 17, 2020 10:39:41 GMT -8
So........try this experiment.
Take two pencils, lay them on your flat table in a "+" pattern. Now take a piece of letter head paper, place it covering the pencils. Place a glass on each corner of the paper.
The paper will not bend smoothly in both directions. It will lay down smoothly (curve) in one plane, but not bend smoothly in both planes at the same time. When you get to the stage of laying down your new aluminum roof skin, it will behave exactly the same way as your paper/pencils experiment. It will lay down nicely either side to side, OR front to back, NOT BOTH, without puckers in the four corners.
The curved rafters were common on many different brands of trailers. and IMO they are basically a good idea. BUT, they are problematic when laying down a new roof skin. At todays cost of new roof skin over $700 (with shipping about $1000) it's very frustrating to have puckers in each of the four corners.
The problem is called a compound curve. It's the reason car body builders have to use English Wheels to stretch the metal in the middle of a panel (roof/hood) to get it to lay down.
My advice is to NOT raise your roof vent, if you already know your going to fight puckers due to the curved rafters. Don't kill yourself with more issues.
You can easily raise the roof vent AFTER THE ROOF SKIN IS INSTALLED. Just slide the 3/4" spacers between the framing and the skin, before you screw down the vent assembly.
The 1" Mule Tape, ratchet straps, and nice flat 2 by 4's are your friends when pulling down on the new roof skin.