condensation

[DcsEAdE]

I have a 12/54 1974 mobile home with new vinyl window vinyl siding a pitched roof. The pitch roof was put over top of the old roof which was a tin roof .Recently I discovered I have soft spots in the ceiling along the exterior walls i pulled down one of the ceiling panels and cut open the vapour barrior and took out the insulation and notice that there was condensation on the tin how can I fix this problem any advise would be greatly appreciated

[JD]

It sounds like the sun is heating up your add-on roof causing the metal under it to condensate. Does your added roof have adequate ventilation? These are guesses on my part. I have no experience working mobile home roofs in cold weather areas. Hopefully Rod will see this post and give you some advice from actual experience.

JD

[DcsEAdE]

The new pitched roof has a large vent at either face of the peak do you think its possible I need a vent at either end to circulate the air between the old tin roof and the ceiling to eliminate the condansation

[JD]

It would be good to know how your roof was built to answer that question. When you said "The pitch roof was put over top of the old roof which was a tin roof", it made me think you now have a shingle roof. If this roof is built with trusses, you may be able to go with eave vents as well as a second roof vent. If there were just nailers and sheathing put down, (besides being a bad idea for shingles) vents may not help. Is there insulation in this added section? Can you describe how it was built?

But again, let's see what an experienced cold region repair person would have to say for you. The coldest temp on record for my area is 30.4F. This year, we may not have even seen a freezing temp. It certainly does not stay that way long.

JD

[DcsEAdE]

I don't know exacty how the new roof was built I bought the place with it already on

[blbrade1]

u said there is a vent at either end is it an actual roof vent or a siding vent if it just a siding vent then your roof isnt vented if this is the case one option could be vented soffit panels u dont want to remove the siding vent cuz u could end up with the same problem on the walls if they sidded over the tin

[DcsEAdE]

i just went out and checked i do have soffit panels

[Rod]

Hello!

I've got questions and some suggestions!

What kind of space between the original roof & the new peaked roof?

Was there any insulation added? If so where was it put?

You mentioned soffitt panels, are they vented.

Is there a vented ridge at the peak or are there just gable vents.

In northern climates the roof cavity should have 1 sq foot of free air venting per 150 sq ft of roof. At both the eaves and ridge. In warmer climates a 1/300 ratio is more common.

So with your 12x54 you should have a minimum of 4.3 sq ft of free air space at the eaves and at the peak.


OK thats the exterior. Now the interior.

With the new windows & siding your home is probably tighter than
before. So more of the escaping air will be through the roof if it wasn't insulated.

What is the humidity level in the house? Get a hygrometer. Typically anything above 38-40% humidity level can cause problems. In a older MH with little roof insulation that number could be lower.

When the warm moist air in your home hits the underside of the cold metal a frost will form. When it warms up it thaws and you have condensation.

Insulation installed on the top of your original metal skin roof may help.

lowering the humidity level may help. The air in your home will gain humidity from many areas. Hot showers, cooking, even more when cooking with gas, unvented gas heaters & fireplaces, pet water bowls, lots of plants, your skin, etc etc etc.
Try to lower the humidity in the house.

Hope this helps

Rod

[Rod]

1 more question.

Was there any kind of vapor barrier (plastic) between the ceiling panel and the metal??

Rod

[DcsEAdE]

they are gable vents
there was vapour barrier
i had a contractor here today and he said that he thinks i should get a turbine what do you think

[Rod]

Turbine will draw more air through the eaves and out the vent.
On very calm days & nights I'm not sure this will help. Or help at all for that matter.

The concern is the condensation is under the skin of the original roof not the new roof so I'm not convinced airflow is the problem.

You could try that.

But get a humidity reading in the house first.

Rod

[DcsEAdE]

Provided I get the humidity reading and it is high, how do I get it down? My wife and I don't think it seems humid in here. I know I'm not an expert but I think the problem is that there is no air circulation in the old roof. Also we borrowed a dehumidifier and it was not getting any water in it.

[Rod]

If you not getting water, your probably ok there. You're not going to feel humidity levels until they are higher than the levels I mentioned.

Your old roof probably never had any circulation. So now after after 35 years it has started to condensate. So something has changed and is causing your problem.

Have you figured out if there is adequet ventilation at the eaves & ridge of the new roof? If there is than I dont believe it should affect the old roof

Is this codensation problem in one area of the home or is it throughout?

[DcsEAdE]

it is through out the place on exterior wall ceilings i would say the new roof is like 10 years old myself my wife and i have only lived here for two years this problem could have been going on for a long time

[Rod]

Hey there!

So its only along the outside walls? Not that center are of the ceilings its that correct?

If the problem has been there for a while I would suspect you would have mold & mildew in the roof cavity?

Possible to get some pics both in & out. And some detail on the new roof. I know you said it had soffitt but is it vented soffitt. Is there a vented ridge?

Rod