You need to make sure that the scope of work on the estimates from the different roofing companies is the same, otherwise you will be comparing apples to oranges.

1. Make sure that your roof measurements on estimates are the same.
   Don't assume each estimate is for the same square footage. Ask each roofer what all the measurements are. They may not want to give you a copy, but at least ask for total measurements - total square footage of the roof, plus all of the lines - the ridges, the eaves, the gable ends, the flashing.

2. Decide on the shingle manufacturer and shingle model in advance.
   Look for what roofing contractors recommend. Ease of installation and warranty are also important. I recommend CertainTeed - excellent warranty and excellent quality overall. Tell the roofing contractor what shingle manufacturer/model you want.

3. Decide on Ridge Profile.
   After you decide on the manufacturer - decide on a standard or high-profile look. Ask for it in the estimate.

4. Specify the underlayment type.
   Tar paper used to be standard, but it is very inferior and is rarely used now. Synthetic underlayment is now standard. Each manufacturer makes their own. Extended manufacturer warranties will usually require using underlayment from the same manufacturer.

5. Ice and Water Shield. How much will be used and where on your roof will it be used.
   Ice and Water Shield is required by Austin code. Specify the brand that you want. Ask where Ice and Water Shield will be used - how many inches (usually 24-72 inches) past interior wall lines, will the roofer also use it at the eaves, the valleys, along walls? Regardless of what is required, you can ask for extras if you want.

6. Ask for Drip Edge at All Roof Edges.
   Drip edges are required at your eaves and also at the gable ends (also called rakes) of your roof. Make sure you get both.

7. Replace Wall Flashings.
   Replacing Flashing is the best practice with each roof replacement. You can not warranty the roof against leaks otherwise, because bad flashing may cause it (and you did not replace it).

8. Specify the Pipe Flashing Type.
   Aluminum or plastic are typical. Upgraded Pipe Flashin is aluminum skirt with silicon boot. But aluminum base is standard - it's called three in one neoprene pipe flashing.

9. Starter Shingle Locations.
   At the eaves only is required (for warranty, but only up to 110 MPH wind warranty). If you also include them at the gable ends - that may increase the warranty to 130 MPH wind.

10. Number of nails per shingle.
    That also affects your wind warranty. 4 nails per shingle may give you 110 MPH wind warranty. 6 nails per shingle may give you 130 MPH wind warranty. Always ask for 6 nails per shingle.

11. Ventilation amount and type.
    Ask for input on if you need more ventilation. You can also download Net Free Ventilation Area Map and figure out ventilation yourself - Shingle manufacturers will have it (it will depend on square footage of the attic). How much exhaust ventilation and how much intake ventilation.
    
    Email me if you have any questions about your roofing estamates.