For most people, that’s foundation and structure issues.

I'm willing to bet 99.9% of them have never been involved in excavating for a foundation, preparing the forms, footings, ensuring the underground plumbing is set up correctly, and pouring a brand new foundation into the Earth.Good luck! 

Great foundational advice on REI for sure.

Also anything that is build in the early 1900 usually has serious plumbing issues and foundation issues.  

I’m currently looking a mentor to help set my Real Estate foundation.

The shed is not cool if it really is one, but my guess is it does not have a foundation, so it's no really a building.On the bright side, sounds like you have long-term tenants, which greatly reduces your turnover expenses.

It explains the team that you should develop to have a strong foundation under you when your investing virtually.https://www.biggerpockets.com/blog/core-four-real-estate-team

If you trust him, and have a solid foundation from the beginning ( which you should, otherwise don't use him ) ask him what his compensation is, and compare it to others to see where he stands.

Signage may be controlled by building codes in your area or special signage codes regarding heights, foundations, electric Lighting Etc...

Building a solid foundation through networking is crucial for overcoming any obstacles that may arise.