roof ventilation question

[blackmon1]

We have a 1987 Homes of Merit Doublewide. It is a 28' X 64' Pine Manor. Several years ago, we put a new shingled roof on the home. We have also added vinyl siding over the existing siding.
My question relates to the roof. When we had some work done on a deck we added, the contractor also helped me with a problem we were having with some kind of moisture stain on a bedroom wall. The staining was at ceiling level where the two sections join. He said we needed to caulk because what was happening was there was such a build up of heat overhead, it was meeting the cool air when the air conditioning was on and because there was a gap, there was condensation happening causing the moisture to build up and run down the wall. Well we caulked and that did stop the problem.
However, he said there was no venting installed when they put in the new roof like there is on most homes. I know in the summer, you can put your hand up near the ceiling and feel the heat. We are in the South and the afternoon sun just beats down on one side of the home in the afternoon, the hottest part of the day. None of our attempts at shading have helped with the heat we feel near the ceiling.
My question is about adding some type of ventilation to the roof. I don't think there is anyway for the heat to escape from what little space is in the overhead. Would adding some type of ventilation help this? If so, what should we add. Our home is comfortable and we have had very few problems with it. It still looks new and is obviously well built. I don't remember having these issues with the old roof, so I think the problem is with the newer one and ventilation.
Thank you for your help.

[email protected]

[rmurray]

My memmory tells me that even in 87 HOM had passive roof vents standard...Maybe the roofing crew took them out to save time...Of course you can and should vent the roof....Any good home supply should have a product for you...The parts stor here has one that is not too expensive..

mobilehomepartsstore.com

The big box stores will have power roof vents which cost more and require much more work to install...

[blackmon1]

I think that is exactly what happened. The roofing crew took them out because the contractor we had later said there was no venting and that was unusual. I'll look at the parts store. How difficult are the vents to install and will that possibly help with the heat I feel coming from the overhead in the summer?

[rbonnie]

Roof ventilation is code required to the formula of 1/300 of the roof cavity floor area (ceiling). At least 50% of the required free ventilation area shall be provided by ventilators located in the upper portion of the space to the ventilated. At least 40% shall be thru eaves, soffit or gable vents. That being said, at the time your home was built, several manufacturers were utilizing a mechanical ventilation system that works off the furnace circulation motor. There were two types. On simply provides air exchange from the outside to inside the home. The other incorporates attic ventilation as well. Generally called a P.O.S. system or Ventilaire. It could have been the later installed in your home. If this was the case, there is a small roof stack immediately above the furnace, which has a flexible duct that runs from the stack to the top of the furnace. You will have to look at your old paper work of get the model from on top of the stack to see which system you have. In any event, if it is not functioning, it must be repaired.

[blackmon1]

Your reply sent up yet another red flag. A few years ago, we replaced our heating/AC system. The person we bought the new one from sold us an all-in-one unit that is located outside the house. It is a gas furnace an electric AC. The old furnace and it fan were inside the house and were removed. I think there may have been a roof stack above the furnace. It so it was sealed off.
We had lots of problems with the new system until we finally got someone from another company to come out and reconfigure the ductwork. The company that initially installed the system also used too small a return according the second company. It is only a 14" X 20" located in the hall.
Anyway, if the ventilation was tied to the furnace, it is probably gone and that explains why we are having such a heat buildup.
Now the question is how do we fix this problem? What type of ventilation do we need to install on the roof. Any suggestions would be appreciated

[rbonnie]

Assuming that you have sufficient eave, soffit ventilation, a series of holes and or vents in the soffit. Soffit is the covering for the portion of the eave that extends out from the home. This ventilation allows fresh air to enter the attic area. The next step would be to install sufficent roof ventilation to provide the 50% of the 1/300 formula. This type of vent is available from any home store. They can be installed only on the rear portion of the roof, as opposed to both sides, for appearance purposes. This will allow fresh air to enter thru the soffit, and exhaust thru the newly installed vents. Position them along the entire length of the home, so that there will not be unventilated pockets.

[blackmon1]

Not sure about the soffit ventilation because of the original was replaced when we put new siding on the house. I'm thinking I need to get a professional to look at that and to install the vents. I looked at the mobile home parts store to see what vents are available through there. What type would be best if I purchase from that source? Thank you so much for your help.

[rmurray]

Your house did have vented soffits...They were aluminum with hundreds of breather holes or vinyl with holes much like vented skirting..You are right you should have a pro check it out and advise your best options..

[blackmon1]

I checked and yes there are hundred of holes in the vinyl on the soffits. So my question now is what would be the best kind of vents to put on the roof? I want to purchase them myself and have them installed because this doesn't sound like a do-it-yourself job.

[rbonnie]

Purchase low profile vents. They are about 12" square, with a flange attached to go under the shingles. They will be marked with their net free ventilation area. Come in various colors to match your shingles.