In simple words, an attic is a physical space between your ceiling and outer roof, built with wood components mostly. As inspectors, we look for any water damage, condensation (the conversion of a vapor or gas to a liquid), and moisture in the attic area, plus any structural damage.

How water can penetrate your attic?

Roof: any damage, missing roof components, and/or labor skills would be a source of water penetration to your attic. This is the reason you should evaluate your roof regularly especially if you live in an area like Seattle by having long raining seasons.

House: Yes, we know water cannot defeat gravity and go up in liquid or solid forms but in gas form, it can. It is good to know the source of water mostly coming from us as occupants of the house. See a normal house with a family living there who have normal activities inside of the house. Cooking, taking bath, or even breathing all produce water vapor (in form of gas) which based on physics rule they tend to move up to the ceiling and then to the attic. On their way up to the attic, their temperature and energy will drop and their form changes from a gas to liquid, moisture. In a badly designed attic, there is a high chance that the moisture does not leave the attic and as a result, affects the wood components there. One sign of moisture damage in the attic would be dark or black wood sheathing (YELLOW ARROW) in the attic which shows moisture intrusion and in some cases, the sheathing should be replaced.

But what you should do about it?

First of all, regular evaluation and maintenance for your roof.

Second, you cannot stop cooking, or breathing in your house so you should make sure all these vapors after passing your ceiling and attic have an exit way to out of your house which in this case Ventilation can be helpful. Insulation in the attic can help you by energy-saving in your house if installed in the proper way and right place which we explain more in another blog.

And how you can provide Ventilation for Attic?

There are techniques to help water vapor produced from the house to exit the house without any harm. By Creating hole and gap in roof and soffit area you will help vapor to pass attic and leave your house, in a passive way, means no energy is required. Sometimes by adding a cardboard named Baffle (RED ARROW) in the soffit area you will create smooth ventilation by removing obstacles like insulation residual on the way of vapor movements. Also, in worse conditions, adding Fan can be helpful to transfer water vapor outside.

Overall, the best practice to remove water vapor from attic without wasting energy, would be using soffit holes and roof ridge ventilation to direct water vapor from ceiling to outside, again in passive way.