Hi, I hope this is right section I am new. I have rats entering my house, I have searched everywhere for entry point and find nothing, all that is left is to inspect where the waste pipe for the downstairs toilet enters the house but this is underground. How deep will it be and is it easy enough for a fairly competent DIYer, and if this is the problem what is the best way to seal entry point and what should I use to backfill. And do you guys reckon that this might be the favourite point of entry? I don't really want to excavate until everything else exhausted, no gaps at surface level and the gutter downspouts have now been covered.Thanks