Roof ventilation change

[kfvoth]

Hi I have a 1997 single wide that I will be reroofing soon. It has the ridge ventilation system now.I do not see any vents other than maybe a small vent on the roof. There is no gable end vents and no soffits as there is no overhand on the roof. I have a flat ceiling in the unit so there is some attic space. I was thinking of putting in three turbine type vents and cover up the ridge vent. I live in a northern climate and wonder if the turbines would work better with snow fall on the roof. Any suggestions would be appreciated.

[Steve S.]

Seems to me that a ridge vent without a soffit vent in a northern climate seems like a very poor design for a mobile home. I think your idea of turbine vents would be a better solution, maybe even a central powered turbine. My MH (1985 Champion) has 5 mushroom-style exhaust vents thru the roof along with the soffit vent inlets. I used to have a central powered exhaust vent but I removed the motor when it burned out and I never replaced it...attic space still seems to vent adequately. I don't know how a ridge vent would work without soffit vents. Where does the cool replacement air come from...inside the house?

[Greg]

What type of roof are you planning on installing? Depending on the style you may be better off incorporating a better vent system in the new roof such as a soffit/ ridge vents. Turbines seem to work ok until the bearings start to go bad then they get very noisy, plus they may be over kill.

Greg

[ponch37300]

Ridge vents are about as good as you can get as far as efficiency of venting, lots of good info out there on ridge vents compared to traditional vents. Yes they do work best in combination with soffit vents that draw air outside air in and vent threw the ridge vent. But even without soffit vents as long as there is an intake of air somewhere the ridge vent is still pretty efficient. There are a few different ways to get this intake of air, adding soffit vents, gable vents, or traditional roof vents down lower. They even make a soffit vent that is round and you can just use a hole saw to drill a hole and pop it in. One thing to keep in mind is that you don't want your insulation touching the roof sheathing anywhere. So if you did decide to add soffit vents you would have to make sure that you have a clear path from the soffit into the attic for the air to flow, the problem comes when the insulation is piled up to the roof sheathing by the walls preventing air flow, they make Styrofoam vents for this that keep the insulation away from the sheathing but those would be pretty hard to install on a MH.

In the cold weather the main problems are from cold air not being able to get into the attic and poor insulation letting warm air out threw the ceiling of the living space. You will notice some people's roofs melt snow faster or you will see the roof trusses outline on the roof when it frosts over. You want your attic air temp to be as close to outside air temp as possible. Most any kind of vents will accomplish this. Doesn't take much to let the little bit of warm air that gets up there out and cold air in.

The real problems I've seen have been from warm weather during the hot months. All sorts of problems can come from the attic air getting to hot. This is where the ridge vent really works. Hot air rises, so the hottest air is going to be at the peak and can get out with ridge vents. With a turbine or other standard roof vent they are usually place down from the ridge a foot or two and have to work harder to get the hottest air out. This may or may not be a huge deal in mobile homes with a lower pitch roof since the peak isn't to much taller then a foot down from the peak. No matter what you decide you need a good "flow" of air, intake and output. Turbines also need an intake to work effectively. Otherwise they are just like a ridge vent with no intake. So no matter if you use ridge or turbine vents you will need to figure out your intake air, otherwise both of them wont' be efficient. If you have the attic space I would add gable vents, easy to do and look nice. The problem will be the middle of the trailer won't have any fresh air intake but it will be better then nothing.

Sorry for the long post, was just trying to explain how the vents need to work as a system for any of them to work good. Lots of great info out there from the manufacturers websites.

[kfvoth]

I would like to thank everyone for the info. I think I will put in gable end vents and go with the turbine vents Thanks again I will be putting up asphalt shingles