Actually it's not a dormer. A ridge perpendicular to the main body ridge. Anybody got a pointer to a web doc that shows the proper way to apply felt?
Here's a sky view of it:
First run Ice and Water shield in the valleys, adhered directly to the roof deck, per the package instructions. Then simply lap the felt well onto the ice and water shield.
On May 3, 4:39 am, marson wrote:
In my area, the ice and sheid in the valleys isn't to code. Metal is needed, and I would recommend that it be galvanized. If the dormer roof slope is above 4 inches per foot than skip the ice and shield altogether. This stuff is mainly useful along the rakes, eves, and on low slope roofs, and in my opinion whether you follow the package instructions to glue it down to the deck or over the paper is up to you. I can't see any reason why it would make any difference after the shingles are nailed down. For the felt, layer from the bottom up, as would shingles, but otherwise paper down anyway you want, making sure that drainage will flow over and off, and not into the roof deck. Vertical rolls are OK, especially along the valley before the metal goes down. Use two layers of 15lb or 30lb, and then nail the metal valleys over the paper. Leave the bottom ends of the metal valleys without nails so that you can put the asphalt shingle or wood shake under before nailing it down. This will allow the drainage off the metal valley to drain onto the roof. Don't nail any closer than two inches from the center of the valley, rather nail the metal down along the edges. Later, you can nail through the valley (still at least 2" away from center though) to hold the shingles down. A little neopreme along the underside of the valley edge of the asphalt shingle will help ensure moisture doesn't get up under the shingles, but it's not strickly required by the shingle manufacturers.
On more thing, put either ridge vent along both ridges, or a galvanized steel roof vent high on the side of the dormer that's hidden from the ground view, close to the junction with main ridge, to ventilate the attic space. You may want more than one of these in the roof. These can be cut in with sawsall after the paper is nailed down. The thermostatically controlled heavy duty electric ones are nice, but for many homes the passive rain protected vent will work wonders.
Do you live in a snow area? The purpose of the ice and water shield is to seal the nail holes. This is required by code where I live. . Ice dams in valleys result in standing water in the valley. Two layers of felt and metal flashing alone will not seal the nails. We too use flashing in the valleys (later covered by shingles, since most people around here use a woven valley), but the OP was asking about how to run felt, not how to shingle a valley.
"Alan" wrote
Oh me lord, we have a hack posting.
"Alan" wrote
Dude, you really are a bozo.
For one, it's not if someone wants more than one vent, there is a formula to figure out proper ventilation.
Another thing, those thermostatically controlled vents don't work in the winter!
Before attempting to give out information on passive venting, please look up exactly what it is. At least you will have a clue next time. Hint: It's not just venting you install on the roof.
Right, Larry. A guy asks how to lay down tarpaper and he starts explaining venting.
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