Moisture Lines on the Ceiling - March 20th 2003


Moisture Lines on the Ceiling



Hi Mr. Busey,

Our home is 5 years old. We have noticed grey lines on the vaulted stippled ceiling. These are wet lines. Doug has gone into the attic, has noticed no leaks around the air vents but when he pulled back the insulation, under the plastic covering the drywall he could see 'grey areas'. We need help in directions where to begin on getting this problem fixed. Questions we have, is the builders responsible still? Do we get an inspector in first? How do we find why this is happening? We will appreciate any directions & or suggestions you could give us.

Thank-you in advance for you help,

Deb & Doug




Hi Deb & Doug,

Your problem is probably caused by excessive relative humidity in your home plus very poor exhaust ventilation (usually caused by inadequate use of a bathroom fan the range hood or the lack of a heat recovery ventilation system (HRV).

The moisture will show up on the bottom of your truss cords where the grey lines show.

First have your home draft proofed.

Next upgrade your insulation in your attic to a value of R40.

Lastly control your relative humidity in your home consistent with the advice provided within the Natural Resources Canada booklet called "Keeping the Heat In".You can obtain this and other information "on-line" by clicking onto the Natural Resources Canada link at the bottom of the home page of my website.

It's Just That Easy!

Shell