Roofing Question from New Commercial Investor

[Eric Hamm]

I just purchased my first commercial property.  19,200 square feet with a restaurant, 2 retail spaces, and 3 offices.  It needs a new roof.  I got two bids when I was doing my due diligence.  The first roofing contractor proposed spraying over the existing roof with polyurethane foam.  The second contractor gave me two bids.  The first was to roof over the existing roof.  The second (which was twice as much) included tearing off the existing roof, fixing all the dry rot, then re-roofing.

The dry rot isn't horrible, but there are a number of areas where dry rot exists.  The price to fix the dry rot and re-roof was $96K.  The price to spray the polyurethane foam OR roof over the existing roof was roughly $45K.

I intend to keep the building for about 5 years then sell it.

If I roof over or spray polyurethane, will that come back to haunt me?