I'm happy to share my two cents with you.Buying rentals and doing wholesale deals will deliver you with two very different types of results.  

Delivered with tenants and cash flowing.

Then two hours later, my tenants delivered an invitation to their mountain wedding in May--it felt good to know that I rented a very nice living space at below-market rent, to a lovely young couple who where able to save up to buy their own place. 

It's my first time inheriting tenants and I don't like feeling like I'm not in the driver's seat. 

Property manager delivers notice to 6 tenants that rents will be increasing between $25-$50 (based on #BR) and we require security deposits. 

If numbers is your driver, you would sell the current primary and take the equity as tax free and then use it for down payment on some better cash flowing rental properties (perhaps a four plex or two duplexes).

Have an Uber driver drive by and take a couple of pictures for you.

I’ve not used these myself for metal roof projects yet, but can report good things from this brand.https://www.lowes.com/pd/Teks-9-x-1-1-2-in-Zinc-Pl...The ones with small washers tend to be used for metal applications and the ones with large washers for spreading the load across surface area (probably ideal for translucent material of a greenhouse).As others have mentioned, the key is to have a decent coating that resists oxidation and a good seal.If these are used for penetrating metal, It’s sometimes helpful to give the screw a light tap with a hammer to keep the screw from wandering, potentially scratching or denting the roof when the driver gets wobbly.

@Johan Yang  Mother's maiden name is a red flag, as well as the driver's license number. 

The best part is getting it delivered and the old one taken away.Then again, you could just fix it if your handy.As far as who is responsible, read your lease and find out!!!