I am in Houston with a 2 story, 47sq, 10/12 slope roof and getting bids to replace my 20 year old composition roof. I'm studying the bids from two highly rated roofer and notice some discrepancies. Both of the estimators seemed knowledgeable, but I'n not sure of which way to go on some options. Hoping someone might give me some input.

Do I need 15# or 30# underlayment?

I have 2 large power vents near the top ridge that quit working and we are going to replace them with ridge vents. One roofer suggested taking out the motors, but leaving the vents in place to allow more air flow. The other says this would disrupt the desired air flow from soffit vents to the ridge vents.?

On GAF shingles, is "Stainguard" a feature of the product or something that is added during construction?

I've had a leak problem where the breezeway from my detached garage connects to my home. Both agree that it's a problem with the rather flat valley that feeds into the breezeway roof. There is currently an open metal flashing in the valley. They both suggest replacing it with the "Stormguard" leak barrier and one would even add a "low-slope" material. Does this seem proper and adequate?

Thanks for any information you might have.

I think I would remove the power vents if they are not working. They provide some natural ventilation but if the ridge vent is adequate they are probably not worth the distraction in appearance. I doubt that they affect the air flow to the ridge vent however. Not familiar with the Stainguard but sounds like something that is a feature of the product. Anything applied after installation would disappear as the granulars of the composition material washes away. Not familiar with the Stormguard but any thing you can do in the valley to reduce the possibility of a leak there is probably well worth the money.