Credit requirements seem to indicate that 10' long compliant mats are to be located at all "regularly used exterior entrances". Now, what do we need to do regarding connections to an existing building that is not part of the LEED project? We are trying to get a School Addition certified, and one of the points of entry (not the only one) to this addition is a door from the main corridor of the existing building. The existing building has mats in all its exterior entrances, but not as long as required by LEED. Do I still need to provide a 10' long mat between existing and new buildings? please take into account that this connection is purely through interior spaces.