Mobile home Cathedral Ceiling designs

[jgcec]

Even though this topic was started 11 years ago, and discussed in some detail, there have never been any pictures that are still available to view.

All past pictures or links to those pictures are no longer functioning.

Basic question
Is the structural half of the mobile home home a closed structure or an open structure.

CLOSED
A close structure would be one would be fully self-contained, and altering it would probably affect the structural integrity of the unit. I assume this is how most of them are since mobile parts are shipped down the highway, and then left for days or weeks at the job site, in two parts, before they are linked together.

Also I recently called mobile home manufacturers and asked if I could get a ridge vent as an option. I have yet to find a mobile home manufacturer that offers it.

OPEN
I find it hard to imagine that it could be an open type system, unless it was designed that way.
An open structure which is similar to the above picture, although it is hard to tell, is designed to allow cross ventilation from one side to the other.

I can’t find an american mobile home that offers a ridge vent and cross ventilation.

If anyone has any pictures of cathedral mobile home designs that would clarify this discussion, please post them.

Is there anyone from coastal California that has any experience with this and how it relates to earthquake codes.

[rooferama]

If you want to know if your home is stuffed with insulation and has no attic area, take a tape measure. Measure the sheetrock inside, then measure outside. You have an airhawk so it might have a truss system. I have probably shingled a 1000 mobile homes in my life. I’ve installed ridgevent on maybe 2, that I can remember. I only did it because the customer wanted it. Doublewides use a 6" piece of flashing, the whole length of the home. It’s purpose is to prevent shear stress. The lag bolts can’t be trusted. Any movement of the home can and do, rip ridge shingles apart, when the metal is left off. When I reroof one and the metal is missing, I place 8x8 tin shingles, every 2-3ft under the ridge.
If you look at the ridge pole of a doublewide, almost all will be stacked with double 2X framing, plus 2 pieces of OSB. They are never bolted tight so you have an inch gap there. Add that up and you have 5 inches before you cut ridgevent. You would have a 7 inch hole in the roof just to get ventilation. That’s a recipe for disaster.
I see many with vents on the gable siding.

[jgcec]

How did you install the ridge vents?

Did you cut 2 slots, one slot on each side?

What did you have to change or cut out for it to work?
I am worried that changing the structure of the mobile home would make it more susceptible to earthquakes, since I live in San Jose CA.

[rooferama]

I think you missed the point. You would have to cut the decking back, past the framing to get airflow. It will leak. Single wides will end up with a 1x8 for the ridge pole. I do not advise you to put ridgevent.

[jgcec]

@Premium_Roof_Service

Ridgevent may work, but on a mobile home they may not be WIDE enough.

Here’s the reason: Because the two halves of the house are joined, and the common wall/joint is at least a double layer of 2x8 or such. So your cut would need to be down below that, on each side.

With your widest ridgevent material at 10", allow for 5" on each side. Give up 2" on each side for the 2x8, etc., you are left with 3". Figure 1" for the vent slot-cut, now you are down to 2" to lap onto the shingles and keep the weather out.

That’s not a lot of coverage for a low-slope roof. It can work, but is also very susceptable to wind and rain infiltration. Remember too, as has been mentioned, that the plywood deck is actually a part of the structural integrity of the “house”, so cutting it back could be risky.

Personally, I would stick with the can vents. Yep, they’re ugly, but less of a risk in this case.

What your saying is similar to what was said in the original discussion.
To Clarify, I have a doublewide, see picture below.

Here’s a picture of my mobile home. Sorry for the confusion with the original picture.

[jgcec]

@rooferama

You have an airhawk so it might have a truss system. I have probably shingled a 1000 mobile homes in my life. I’ve installed ridgevent on maybe 2, that I can remember. I only did it because the customer wanted it.

A contractor with Certainteed said that In his experience any roof that is below a 4/12 pitch and uses a ridge vent will have leaking problems.

If I installed a ridge vent it would have given me about 500 square inches of NFVA on each side of my house.

Currently I only have 200 NFVA on each side, so I am looking for ways to increase the exhaust capacity without using a ridge vent.

My current soffit intake capacity on each side of the house vents is about 900 square inches and my exhaust capacity is only 200 with 4 air hawk events.

What about using a few power vents, or replacing the 4 air hawk vents there are 50 square inches with the larger vents that are 150 square inches?

My living room and family room is basically all one room in the middle of my house, so what about just replacing the vents that are over that area?