Raining In The House

oldfrt

Here's one I haven't seen before:

A client calls me up to help with his moisture problem.I figure it's an walk in the park kind of job.When I arrive he tells me that he has had droplets forming on the ceilings of the house and in his garage they actually drip to the floor like rain,his words .not mine.
The house is a basic 40x24 ranch with attached garage and a full basement.The foundation is a poured wall as apposed to block which was sometimes problematic for leaking.There is a concrete floor in the cellar.
There is a ridge vent and gable end vents and about 3.5 in of insulation between the ceiling joists.and there is an access door to the attic space through a scuttle hole in the gable end of the house where it meets the house.The garage has a plywood ceiling .
The only time he notices this problem is when he runs the wood stove,which is in the cellar of the house.
I'm thinking that the heat from the stove is carrying the moisture from the cellar up past the insulation into the attic area.The existing insulation is the old double faced bats,used back in the 40's and 50'saround here.
It probably no longer has a functioning vapor barrier because of its age.

My fix(if I get the job) was all new insulation w/vapor barrier,nix the gable end vents and add soffet vents,waterproof the interior of the basement walls,possibly the floors also,repair gutters to get water away from foundation.There is no visible drainage pipe to account for curtain drains ever being installed.Most of the property slopes away from the house.
A lot of work just so the guy can fire up his wood stove,it'll probably cost as much as a couple seasons of heating oil.

I was curious as to whether anyone else has come across this situation before?

concretemasonry

He must have a horrible humidity ptoblem. - Did he even check the humidity.

The only way mositure will form droplets is by condensation on a cold surface. The ceiling surface must be below the dew point.

Apparently, the ceiling insulation is not sufficient for cooler weather. When he heats, the warm, humid air rises, forming the condensation. The moisture is not being carried into the attic area.

Never get rid of the attic ventilation!

__________________
Dick

Engineer, designer and consultant recently active domestically and internationally on construction and design in about 35 countries.

oldfrt

Never get rid of the attic ventilation!


Actually,I was going to add soffet vents in lieu of the gable end vents so the air would vent up from the lowest point in the attic.

So,because this only happens with the wood stove in use,wouldn't this mean the damp air from the cellar is the root of the problem?It doesn't happen when he uses his furnace(baseboard heat).

So,if the ceiling was kept warmer by the use of added insulation,this should remedy the condensation problem,even though it doesn't happen while running the furnace.
The biggest problem seems to be on the ceiling of the unheated garage.The scuttle between the gable end of the house to the garage attic area is always open.

neolitic

Get rid of the vapor barrier in the attic. And don't even try to retro fit one.
It'll just cause a problem, not solve it.
Does he have bath vent fans, and use them?
How many people? Lots?
Vented range hood?
One of those idiotic dryer vent diverters? Those things will turn a house into a freakin rain forest.
Maybe just a dryer vent so plugged up it's non-funtional.

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(Sorry....it seems there really are dumb questions)

Tom M

Concrete masonry is right. You have a vapor retarder that is keeping the water from passing through. So either remove it and put Batt insulation in to allow moisture to pass through this well ventilated attic or introduce ventilation down by the burner to dilute the moisture with addition air.

oldfrt

Thanks guys,
I'll double check that dryer vent situation.The bathroom and kitchen fan are properly installed.

Michaeljp86

I think the problem is the attic is cold and there isnt enough insulation. The cold air in the attic makes the ceiling cold. Then he fires up the wood burner and gets its about 90 deg in there and the warm moist air floats up and hits the cold ceiling and condensates.

Tom M

Also check out the vent pipe itself. Single wall pipe is not allowed to pass through a cold attic. It will condense, rust and drip as well. It should be a B-vent.

oldfrt

Well,I called the HO,gave him a verbal estimate after telling him what needed to be done.He wants me to mail him an estimate.
He only lives about 2 miles away so now I feel he just wanted to find out what had to be done so he could do it himself.

So now he's waisted my time and yours.
Thank everyone for your response.
I guess I'll just mail a bill for the estimate first!!!

Michaeljp86

Post his name and address on here so we can all send him a bill.