capping a garage roof with NO ridge vent?

[Ironman1079]

i have one last row of shingles to install on my garage....the final cap.

i am gonna start at the non weather side and work towards it.

my book says cut the tabs 12" wide and narrow them down to 10" and overlap them.

is this correct, some people are telling me its not?

[AllanJ]

When you cut the typical shingle at the slots to get pieces for the cap row, you will end up with three pieces each 12" wide. You don't have to cut them again to be 10 inches wide unless the roof will look better that way. Do a trial fit with two or three of the pieces. Note: The cap shingles when folded over must go down each side at least 4 to 5 inches even if that makes the topmost row of regular shingles look thinner.

I trust that there is 5 inches or less of black (ungranuled) portion of shingle exposed all along the top ridge. Otherwise you need to add yet another regular row of shinges. When you fold the pieces for the cap row over (half of the black and half of the granuled part going down each side) and nail them on, there should be enough overlap so they too do not have exposed vertical strips of black.

"Pardon, your slip is showing!"
On some installations it is possible you may wish to trim the black part of a cap piece to be a little less than 12 inches while the granuled part remains at the full 12 inches so you don't see a thin horizontal line of black below where the next cap piece is installed. This is cosmetic only; since the granuled part of the topmost regular shingle is underneath, there is no leakage problem.

In addition the very first cap piece should have something under the granuled portion to make a total of at least two layers over the thin gap along the peak. Customarily the granuled part is cut away from a cap piece and the remaining black part put up there to start the cap row with. If more than a few inches of excess material from the topmost rows of regular shingles got folded over at the peak leaving no gap, that would suffice as a second layer.

(Clarification added 9/7/06) "Granuled part" here means the part, typically no more than 5 inches high, meant to be exposed when the shingle is installed on a normal horizontal row of same. (After visiting a building supply store and discovering that most shingles have granules over the entire surface although only the exposable portion might have the correct color.)

[iain]

place the ridge cap so that they will go with the most common direction of wind in your area it will save some fixing after a good wind storm