I've tried to figure out how to aligh that methodology into the STR world.

@John Dais  I would recommend a good engineering-based study so you can sleep at night knowing you are using the IRS' preferred methodology.

What's your methodology for determining the quality of the roofing replacement?

Wouldn't mind getting a copy of that for myself if he doesn't mind sharing.Materials are actually much easier to estimate (and generally a smaller percentage of the total cost) than labor.I just finished up writing a book on how to estimate costs (labor and materials), and will hopefully have it available soon...it should at least provide a methodology for determining your local prices.While I do have a SKU list, it's just the basic finishing materials -- light fixtures, plumbing fixtures, appliances, water heaters, doors, etc.

While the name sounds a little fluffy, it was an amazing class that really put a methodology and true strategy to the art of negotiating. 

@Bernard Reisz Another important question to keep in mind is what methodology is being utilized for the report as there are six commonly used methodologies that are recognized by the IRS.

If you have hired a specialist to perform a cost segregation study of your real estate property, they will likely use one of the six most common methodologies recognized by the IRS.

@Phil Shelton  The IRS' recommended methodology is an engineering-based study.

I've recently been introduced to the Profit First for Real Estate Investing methodology and I'm excited to implement it! 

Now via methodologies such as BRRRR (or any value add associated with a refinance that extracts value), the $100k property can be owned with $0 investment producing infinite return.