F.U.B.A.R.
Bluelight Crew
Yes!! I deffo want that T-shirt 

Pennywise trying to steal your sanity and make you his minion?
Almost certainly surface water entering the foul water sewer (if they're even distinguished in your area), and pushing more air in front of itself than could escape via any vent pipes between it and you.
Re. the loft project. After a chance encounter with one of my lovely neighbours this evening, I have been given a metric shitload of Canadian hardwood tongue & grooved floorboards for free.![]()
Tell ya what, give us a tenner and I'll take it off yer hands for ya. I'll even let you off the tenner if you deliver....