Can Fan solve water condensation issues in attic?

[q0987]

Hello all,

We found water condensation in the attic and the roofing company suggested that we should install an attic fan and said the ventilation of the house is not enough. The house is townhouse and with several vents on the roof. When the builder built the community, none of the houses have attic fan.

Question 1> Should I install attic fan to solve the water condensation issues?

Question 2> I started to look for holes/air pathway in the attic and use expansion foam/caulk/aluminum tape to seal them. I hope I can cut the heat/moisture air into the attic.

I also see this article which says attic fan is NOT good.
http://www.energyvanguard.com/blog-...c-Suck-Power-Attic-Ventilators-Are-a-Bad-Idea

What is the better way to solve my water condensation issues?

Thank you

 

[oldognewtrick]

I really don't think you have a condensation issue, you have a roof leak at the static vent. A fan will help draw out moist air, but you will need to block off any other static vents on the roof for the vent to function properly.

Oh yeah, to House Repair Talk!

 

[q0987]

Hello Sir,

Thank you for your feedback.

Originally, I also thought my house has roof leaks but here are some facts.

We don't experience any leakage during heavy/storm rain fall. The only time we experience some dripping/water mark in the top floor ceiling is during the time when temperature goes above freezing point where the freeze ice on the inside of the roof melts.

The picture I caught is during the time when the temperature is above freezing point and the ice has melted.

In the extreme cold weather, I can see frost in my side walls of attic and also see frost built up around roofing nails and plywood.

Another fact is that my top floor has humidity of 47% which the roofing company said it is way too high. I talk one of my friends who control the humidity in the house around 20% during winter time.

Question 1> Is my humidity too high and will it damage my house? I have set my furnace humidity level to 10%. My wife always complains that decreasing humidity lever makes here feel uncomfortable.

Question 2> What is the better humidity level in the house during the winter time?

Question 3> Should I seal the pvc venting pipe up to the roof? I saw lots of ice/frost built around that area?

Question 4> "A fan will help draw out moist air, but you will need to block off any other static vents on the roof for the vent to function properly." Why should we block all other static vents? That will increase the cost of the whole job, right?

Thank you

 

[oldognewtrick]

Things to check for:

-How many exhaust vents do you have on the roof?
-Do you have intake ventilation along the eaves to introduce air into the attic?
-If so, can you post a pic of that?
-Is the area around the eaves stuffed with insulation, thus restricting the air flow?
-Does your bathroom exhaust ventilate out through the roof deck or does it terminate into the attic?
-Have you noticed ice formed on the underside of the roof deck during freezing temps? Can you post pics of that?
-Do you have standing water in a crawl space under the house?

The reason you want to close off the other vents, if you have any, is it will short cycle the attic exhaust. Meaning, when the fan comes on, it will draw air in through the exhaust vents and not pull warm, moist air out of the attic from the soffit area.

If you have a power vent installed, make sure it has a humidistat control and a temp control.

 

[nealtw]

The moisture in the house should not effect the attic unless you are loosing lots of air from the house.
Where do you exhaust leave the house , bathroom fan, range hood fan, dryer vent. If these vents are near the soffet moisture will be sucked uo into the attic. This kind of moisture is usuall caused by something pumping moisture into the attic.

 

[AU_Prospector]

-Does your bathroom exhaust ventilate out through the roof deck or does it terminate into the attic?

THIS^^^^^^

I would lay a Jackson on the table and say your bathroom exhaust fans vent to the interior of the attic. Cold roof = condensation which freezes inside the attic. An attic fan will do only one thing...

Suck the desirable air inside your house through ever nook and cranny and into your attic. You dont want to pull your air conditioned air out of your house and into the attic in the summer. This will increase your energy bills according to TVA.

Also you state you are plugging every vent hole in your attic. You will make the situation worse doing this.

 

[user 4883]

too high up to be "ice damming", gotta be exhausting something into the attic, possibly soffit vents are covered with insulation ?

 

[oldognewtrick]

Another post where you wish the op would come back and give an update...

 

[AU_Prospector]

By now he has either....


Question 1> Should I install attic fan to solve the water condensation issues?
Sucked most of the conditioned air from his living space into the attic

Question 2> I started to look for holes/air pathway in the attic and use expansion foam/caulk/aluminum tape to seal them. I hope I can cut the heat/moisture air into the attic. Or initiated mold growth on the interior roofing frame and sheathing

 

[Perry525]

People create water vapor by washing, cooking, breathing - for a start.
Water vapor is pulled into the roof by the passing wind and sometimes because warm air rises.
When the inside of the roof is below dew point, condensation forms on roof.
Solution.
Use an exhaust fan in the kitchen and bathroom to push warm wet air outside.
this will pull colder drier air in to your home through all the cracks and holes.
Block all holes between living space and roof.
Paint ceilings with either gloss paint or latex paint = both are water vapor proof.
Note:
Most roofs get very hot in summer, the heat dries the wood, mold tends to dry up and disappear. Mold needs wood as food and water from the air to live.

This may help someone else.