Just want to exhaust this option before I go to a cash-out refi.

I do not unless it is an emergency so the pipe bursting recently was flooding their home and unfortunately they didnt know how to turn the water off regardless that I told them how before etc! 

I've had so many deals fall through this year and am feeling exhausted from putting in a lot of time and energy to deal I thought were going to be solid an they ended up falling through. 

It's probably a vent pipe for a furnace, water heater, or something similar.

By no means is this an exhausted list.

You have to keep your eye on the total market cap and compare that to news that is being announced in real time, it can be exhausting.

Assuming adding a vent isn't unduly difficult, i.e. the dryer being in an interior room far from an exterior wall and/or no good access to run dryer pipe, I would put it in on my own.

Some that come to mind but not an exhaustive list in/around the city are Brighton Heights, Bellevue, Avalon, Carnegie, Crafton, Ingram, Beechview, Brookline, Troy Hill, Millvale, Etna, Sharpsburg, West View, Greenfield, Brentwood, Coraopolis, Bridgeville. 

There were exposed water lines and pipes in the rooms and missing doors.

I had an estimate done ($7k) because at this point the sprinkler piping is exposed and I'm afraid that could lead to an even greater problem.