Common Rodent Access Points for rats: -

1] Holes near cabinets  
2] Holes around sink  
3] Cracked foundations in the basement  
4] Holes around windows or doors.
5] Attic
There are many entry points wherein Rats can easily get inside the house and can damage everything. To get rid of such rodent issues, one should take some help from professionals like Rodent exterminator NYC.