- A 30 year roof will cost about $.065 cents per square foot per year if the roof is overlaid, and about $.09 cents per square foot per year if the roof is torn off.
- A 40 year roof will add ten years to the roof life, at a cost of $.025 cents per square foot per year. If you adjust for the time value of money with a two percent difference between investment and inflation your 40 year roof will cost $.045 per square foot per year.
So the only reason not to buy a 40 year roof is because you are going to sell your home soon or you just don’t have the money. There are other legitimate reasons not spend money on your roof, however the economics of a 40 year roof are sound.