Landfills make me think: odor, smoke, noise, bugs, and water supply contamination.Construction on top of landfill: additional costs, abnormal settling, off gassing, heavy metals, and surface leaching if a capping fails.

@Sam Booth Yes to the Oil based Kilz on the sub flooring or something similar to help kill the odor.

If there's no odor, tell him there's no odor and you're not going to pay a plumber for nothing.

On inspection I found newspapers and stuff stacked over my head; an overpowering but vaguely familiar odor; and a thick grey dust on everything.

One thing I would be concerned about however how often do other people around your place smell tobacco/ vape odors.

The house I bought had a strong pet odor, cat urine, and as part of the scope of work, I asked contractor to eliminate that odor, however house was repainted and work 99% complete, but odor came back.

They still would have the ability to call foul on you, which you would have to defend yourself.

Easier to clean, don't hold odor, and they hold up better.

Also, ODOR is a huge issue.

Then go ahead and place that document (LOI and PoF) in an envelope and mail it to the PO Box in Pennsylvania, again dated the current date. 9 times in 10, this is where all their other bills go, so it's a mailing address they actually check.If the listing broker is doing their job, then there's no harm and no foul.