Proper ventilation has a significant effect on the lifetime of the surface. Improving the ventilation of your roof helps regulate upper temperatures during the summer and reduces the accumulation of moisture in the winter. Ask the contractor whether it will include features such as gullies and hills http://businessinfo.over-blog.com/2019/06/some-most-important-things-to-consider-before-planning-re-roofing/roof-replacement.html