When re-roofing in WA state with 20 year asphalt shingles what is my roof venting requirements, where can I look that up, and what is the best way to go about installing that venting?

A 20 year shingle is the lowest warranted shingle, thinner and less able to stand up to the environment than all others, If you can get a better grade( 30, year) you will be a lot happier with this product in the long run, and the price difference is nominal.

As to venting, ridge venting is the latest craze... an opening cut through the ridge to allow air to escape throughout the entire building, capped off with ridge.

The packaging will show how to install it( if your home doesn't have ridge venting already, you'll need to cut the ridge, preferably before the shingles are up to that point)

Otherwise, a power vent has ratings for how many square feet you need to ventilate, and how many units you might need, Washington State is a very moisture laden state and you might look for a moisture/heat activated power vent to accommodate your local.

If you want to look it up, look for roof venting in a Google search.

Are you east or west of the Cascades? Western Washington needs about 1 square foot per 300 square foot (50% high and 50% low) and Eastern Washington can get by with less. The inspector at your county building department can give a definitive answer. Haven't talked to the local building inspector? Most counties and municipalities require a building permit for re-roofing. Even if they don't require a permit:rolleyes: , you are still required to re-roof according to their standards. Not following local codes and standards could result in lowering the re-sale value of your home:eek: .