How did you all calculate the cost of specific items such as; window, doors, roof, HVAC, cabinets, etc?

So I just have her do everything but the solo 401K specific items such as annual compliance.  

There are standards of practice and specific items that they are required to address and note as deficient or missing. 

Before they moved out, I sent email twice on their lack of maintenance on the garden, and specific items that were totally lack of maintenance, upon which they never replied.

Then you can start asking questions that have you confused about specific items.

In addition, I wouldn't list charges for specific items.

They typically have a "designer" or "consultant" for free that can give advice (or research in your case) specific items.

I give tenants time to explore and discuss by themselves before reviewing specific items with them.

If you are doing the demo yourself, look into the protective gear you need so you don't breathe it in or get it in your eyes (I'm not a contractor but my understanding is that asbestos fibers are very tiny and there are specific items you will need to properly protect yourself). 

If it is new construction, your need for cost segregation is MUCH less actually, because your have a predetermined cost of specific items.