would heavy trucks be helped by Steve’s LFRolloff filter?
You can see it working.

Steve’s Rolloff changes with the “Length” setting. The actual activity is the thin green line, not the heavier blue one. The green line “tightens up” with higher lengths, but the possibility of sound damage goes up.
The filter is designed to suppress both 50Hz and 60Hz, the base power frequencies in Europe and the US, and in effect, elminate everything below them.
85Hs is too close to 100, so no. It won’t have any significant affect.
Is it trucks? Does it come and go with traffic? It might be good to go looking for it rather than throwing in the towel and fix it in post.
Is there a straight line hardware path from your microphone to the floor? That’s generally not a good thing.
For a long time I had Magic Spot in my studio where the hum and noises went away. It was remarkable. A couple of inches any direction—up, down, sideways—and the hum would come back. One day I climbed into my headphones, fired up my tiny field sound mixer, taped my microphone to a stick and went around the room like that guy at the beach with the metal detector. Found it, too. Turns out my powered music bass cabinet doesn’t go off when I switch it off. It stays running spraying low level hum both electrical and sound.
85Hz doesn’t sound important other than possibly that’s the frequency your house “likes.” Rooms and buildings like certain tones. When just the right tone comes by, the room rings like a bell at that tone. It doesn’t have to be metal and it doesn’t have to be shaped like a bell. Rooms and buildings ring, too.
Los Angeles has done some very serious research on making buildings ring in such a way that earthquakes don’t turn them into expensive debris in the street.
Post some of the room noise (Room Tone). 10 second WAV should do it. Scroll down from a forum text window > Upload Attachment > Browse. No filters or effects and don’t “help it.” Just the noise as you normally experience it.
Koz