I am having trouble with my web service in ASP.NET - sql

Question

I have written a webservice to access my SQL database.
[WebMethod]
public void getRoomByBuildingID(int buildingID)
{
string cs = ConfigurationManager.ConnectionStrings["vetDatabase_Wizard"].ConnectionString;
List<Room> rooms = new List<Room>();
using (SqlConnection con = new SqlConnection(cs))
{
SqlCommand cmd = new SqlCommand("spGetRoomsByBuildingID", con);
cmd.CommandType = CommandType.StoredProcedure;
SqlParameter param = new SqlParameter()
{
ParameterName = "#buildingID",
Value = buildingID
};
cmd.Parameters.Add(param);
con.Open();
SqlDataReader rdr = cmd.ExecuteReader();
while (rdr.Read())
{
Room room = new Room();
room.ID = Convert.ToInt32(rdr["ID"]);
room.Name = rdr["Room"].ToString();
room.buildingID = Convert.ToInt32(rdr["Building"]);
rooms.Add(room);
}
}
JavaScriptSerializer js = new JavaScriptSerializer();
//Serialize list object into a JSON array and write in into the response stream
Context.Response.Write(js.Serialize(rooms));
}
I keep getting an indexOutOfRangeException at
room.building = Convert.ToInt32(rdr["Building"]);
I've been looking at my sql table, and the column names and types are correct (i.e. ID, Room, Building). I am totally clueless at this point and would greatly appreciate the community's feedback. Thank you!
EDIT:
ALTER PROCEDURE spGetRoomsByBuildingID
#buildingID int
AS
BEGIN
SELECT ID, Room, Building FROM tblRooms
WHERE Building = #buildingID
END
EXEC spGetRoomsByBuildingID