However, the recreated roof did not replicate the Madison-era shingle fragments in every detail.  The Madison-era shingles found in the house were made out of both heart pine and American chestnut while the shingles used for the restoration were cypress.  Why would the Restoration Team blatantly disregard the historical evidence?  As it turns out there were problems with both historical wood types.  Heart pine was rejected because it is not weather resistant and so would have rotted in twenty or thirty years.  By failing so quickly, the heart-pine shingles would have potentially resulted in damage to the surviving, and irreplaceable, ca. 1764 and ca. 1797 roof framing.  Chestnut on the other hand is a very rot resistant wood and so would have been an ideal choice for the new shingles.  However, because of a devastating chestnut blight that killed almost all of the American chestnuts by 1940 there was not enough suitable wood left to produce the 80,000 shingles needed for the mansion.