For quite a few years now those "screws" (bolts actually) have generally been made of a nylon or plastic material, with large thumb type wing nuts to secure them from the bottom while the head is held with a large straight blade screwdriver.

If you own the house you could either install one or attach plastic to front opening for one rain storm and see if the problem persists. 

I understand leverage and utilized about $15k in plastic to remodel my current primary last year. 

[Case Study: Our bubble bath loving tenant who burned tea candles in the soap dish of a plastic tub surround and burned a hole through it.

If you put foam board in, make sure you peel of the sheet plastic, you'll get condensation that may run down dripping off in the wall cavity causing problems.The much better solution would be a metal roof over the old.

An effective way to check for moisture in the slab is to tape down a 2' square piece of plastic on the slab and leave it for a day or so.

I just had another tenant (on a 2 year lease) ask me if it's OK to have a new high end black plastic coated chain link fence professionally installed with permits at his cost so their Lab doesn't need to be on a 'stringer' anymore.  

@Todd Fry I am truly sorry for your experience.

the tenants are also cool with covering the windows in plastic wrap i the middle of winter to eliminate any draft...none of these tactics did the previous owner do.  

If your worried about the planet Google "plastic island"