Ridge vent on mobile home?

I’ve got a double-wide mobile home job that is wanting ridge vent. Currently it has 4 square vents, and cathedral ceilings. Unless the mobile homes are built with cross-ventilation designed in, there are only 4-8 rafter bays being vented here. I’d like to remove them and use ridge vent. Is there any problem cutting the slots in a double-wide for ridge vent?

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it depends on the pitch.

Pitch is 4:12 . ShingleVent II is spec’d for down to 3:12 .

But the question is, does the roof structure of a double-wide (particularly at the ridge where the two halves of the house join) preclude ridge vent or is it okay to cut the vent.

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.

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The halves are constructed of trusses. The center piece of each half is usually plywood and some 2x4. I’ve vented 2 without any trouble. If i remember correctly, there is space between the two halves.

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If there are no soffit vents present then you can not use ridge vent without eave vent product. Also like stated earlier the ridge will have double ridge beams and might not work with ridge vent. Hence we forget you will need to use baffles if there are soffits.

Here is a thread link to my photo storage forum that shows a 3/12 pitch manufactured home, that not only has Shingle Vent II Ridge Vent installed continuously, but also Smart Vent along the Eave Edge on one side and as a Mid-Roof Application on the other side, due to the garage modular section not allowing continuous upward air flowage from that eave to the ridge.

rightwayroofing.freeforums.org/m … 07-t6.html

I work on a lot of manufactured homes and always use Shingle Vent II Ridge Vent on them.

Ed

[quote=“ed the roofer”]Here is a thread link to my photo storage forum that shows a 3/12 pitch manufactured home, that not only has Shingle Vent II Ridge Vent installed continuously, but also Smart Vent along the Eave Edge on one side and as a Mid-Roof Application on the other side, due to the garage modular section not allowing continuous upward air flowage from that eave to the ridge.

rightwayroofing.freeforums.org/m … 07-t6.html

I work on a lot of manufactured homes and always use Shingle Vent II Ridge Vent on them.

Ed[/quote]

Now, really, Ed… “flowage”???

Anyway, the pics are great, and thanks for the info. I don’t understand what was so confusing about my question that about half the responses related to things I didn’t ask.

We did the roof today. I could never get the manufacturer/model info from the HO so I could call the company, so I took full ridge vent as well as replacement low-profile vents just in case. When we pulled off the old roof, and peeked under the strip of 10" galv. over the ridge, we discovered … NO lumber at all running along the ridge, and a vent slot already “cut” (i.e. the decking didn’t even come close to meeting at the top). Did the whole main ridge in ShingleVent II. If that SV-II had the fully overlapping interior baffles and end-to-end overlaps from TAMKO Cool Ridge, it would be the cat’s meow.

Only trouble with the job was a junior roofer who didn’t chalk any guide/recovery lines for the 3-tabs, and we ended up having to tear off 1-1/2 squares because they were so crooked. (I left during tear-off to go check out another house - bad idea with a new crew.)

Looks like junior just lost 2 days pay.

Chalk it up to experience. Thats how they learn what is acceptable or not.

Ed

[quote=“ed the roofer”]Chalk it up to experience. Thats how they learn what is acceptable or not.
Ed[/quote]

Yeah, no point in being punitive. The crew boss took over and re-did it. The crew is a sub, so I’ll pay for what got done right, not how many shingles got used, and they’ll sort it out internally. The young guy will do better next time.

I was gonna say that most double-wides you don’t even have to cut the ridge as its already cut.

I am tearing off the current roof and putting on a new roof on my cathedral ceiling mobile home, made in this year 2000. One roofer has suggested using a ridge vent.

It has approximately a 3/12 pitch.

can anyone provide updated photos or diagrams of how this would work?

If you have cathedral ceilings inside (ceiling sloped, attached to the bottom of the rafters) then you will certainly have insulation filling the space between the rafters, ceiling, and roof. No way to ventilate that with major reconstruction (e.g. build a new roof on top of the current one).

-neville


CORRECTION AUGUST 8TH
THIS IS FOR A REROOF
I am not wanting to build a new roof just install a ridge vent in the existing one. MISLEADING AND NOT ACCURATE

I cannot find any diagrams of what my existing roof structure looks like.
Here is a picture of the inside of the house with the 2x8? Running the length of the house.

I’m not sure if I’m interpreting your photo correctly (I think I am, but not positive). Let’s try this:

Are the ceilings flat (parallel to the floor)?
If not, then the ceilings slope up toward the center (where the two halves of the home are bolted together), right?

If the ceiling slopes up, and appears to follow the same angle as the roof, then just give up on the ridge vent idea. You will only have available the 6" (nominal) space between the ceiling and the roof deck and it will be (certainly should be) filled with insulation to protect the interior of the house. This protection comes at the expense of the roof, though. Unless you pull off the roof and the roof deck and pull out the insulation, then put back the deck and new roof, you can’t ventilate that roof in any workable way.

If the ceilings are flat (parallel to the floor), then you have an attic space where air can flow which means you can ventilate (with ridge vent, if you like).

I corrected the previous picture and it’s rotated at a 90° angle. It is a cathedral ceiling. Not a flat ceiling that’s parallel to the floor. There’s that beam that you can see near the peak of the roof, which are probably 2x8s that runs across the house.

if you look at the street view of the house you can see the 2 square vents, but there are actually four, near the peak of the roof, and then under the eaves are four intake vents on each side.
So there are four intake vents and four exhaust vents on each side of the roof.
One of the proposed roofers wants to eliminate those square vents and install a ridge vent. Personally I don’t think it’s a very good idea because of all the things that could go wrong and screw up my house which is also in earthquake country.
If you haven’t been in a strong earthquake it’s hard to imagine how much shaking there is and how much strain that puts on the house.

This description (and the photo) are strongly reminiscent of the mobile home that started this thread 11 years ago. We do not roof very many mobile homes, but a few years ago we did an entire park (304 squares in one day; it was quite a sight) and there were such differences between methods of roof framing that I cannot confidently tell you what to expect with yours. I think the very best thing you can do is to call the manufacturer and speak to a tech service rep to find out whether those 8 vent pairs vent the entire roof or just 8 rafter bays (or perhaps 16, if each vent straddles a rafter).

Either all the rafter bays have to be baffled (great design), or else it would need to have no insulation in the bays (horrible design). In either case, you could probably use ridge vent (if it is wide enough to reach past the wall structure / beam-half / etc. at the ridge, to reach the airflow. If, however, the bays are insulated and not baffled in some way to allow air flow, then there is no point in attempting this project (unless you build a new vent-able roof atop the current one, which you (quire reasonably) rejected.

Do you have, or can you get, the manufacturer’s contact info and your home’s model info?

-neville

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Fleetwood went out of business in 2009 and was bought by Cavco which renamed it Fleetwood Inc.

I did talk to a guy from cavco the other day he was very knowledgeable.

He did not know the roof design of that particular model that I have, which is called a suncrest 5604B, which was built in November 2000, at the woodland California plant near Sacramento.

Why is it that no new expensive $300,000 to $400,000 range mobile homes near me that I have seen installed in the last year or so use ridge venting? They all use the same square venting like my mobile home does and most of the other ones in our neighborhood.

Since there is so much uncertainty about my roof, and I have more to lose than to gain from a poorly done job, I’m going to skip it at this point and just go with a regular contractor using the existing venting system, unless someone can convince me otherwise.

Also the GAF salesman is an idiot. First he wanted me to do a roof over my existing roof which isn’t allowed in mobile homes. Then he was trying to sell me on a LowE rereflective barrier for an additional $2,000.

Then he changed his mind and said that he couldn’t do a ridge vent, then he changed his mind and said that he could do a ridge vent.

He says to trust him, because he knows what he’s doing or the company knows what they’re doing. I did call of several of their referrals which seemed to be happy with their work. If I did not get this particular salesman maybe I would believe that.

I’m sorry that I can’t help you more. If I was there, and doing the re-roof, I would plan for both types of venting (existing vs. ridge vent) and pull up 2-3 sheets of decking once the old shingles are off. That would allow me to see the construction and would immediately answer all the open questions.

Don’t judge GAF by your roofer’s salesman. Even if GAF connected you with this roofer, they can’t control the hiring or salesmen. This fellow might have been a hairdresser 6 months ago and is now out of work and needs an income so he turned to selling roofs. It is unfortunate for the homeowner, but that sort of thing happens a lot. I will take referrals from the few other roofers that I know and respect, but have had and known of so many problems with salesmen that I don’t use them.

As for the heat barrier (sounds like Polaralum or possibly a copycat) I don’t want to get into a debate with anyone about the efficacy of that material, but I will tell you that I like it a lot and have good pre-vs-post reports from several customers that it transformed certain parts of their house from unlivable to quite comfortable. It is approved by most shingle manufacturers to not void their warranty, BUT unless you determine that your roof has an adequate ventilation system AND you are NOT using modified-bitumen-based Class 4 Impact Resistant shingles, then steer clear of it. If you don’t meet those conditions, then i promise you that your shingles will blister and there will be a finger-pointing-circle when it comes to determining who is going to fix it.

Please post a followup here when the project is completed and let us know how it all worked out.

-neville

jgcec
August 5

Fleetwood went out of business in 2009 and was bought by Cavco which renamed it Fleetwood Inc.

I did talk to a guy from cavco the other day he was very knowledgeable.

He did not know the roof design of that particular model that I have, which is called a suncrest 5604B, which was built in November 2000, at the woodland California plant near Sacramento.

Since there is so much uncertainty about my roof, and I have more to lose than to gain from a poorly done job, I’m going to skip it at this point and just go with a regular contractor using the existing venting system, unless someone can convince me otherwise.

Also the GAF salesman is an idiot. First he wanted me to do a roof over my existing roof which isn’t allowed in mobile homes. Then he was trying to sell me on a LowE rereflective barrier for an additional $2,000.

Then he changed his mind and said that he couldn’t do a ridge vent, then he changed his mind and said that he could do a ridge vent.

He says to trust him, because he knows what he’s doing or the company knows what they’re doing. I did call of several of their referrals which seemed to be happy with their work. If I did not get this particular salesman maybe I would believe that.

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