Rehab costs - tax deductions?

[Tony Kempisty]

We are starting our rehab next week on my 1st rental property. The house is in rough shape so we'll be doing a good bit of work:  new roof, windows, flooring, cabinets etc. 

How much of this can I deduct as repair costs?  

From some basic googling I understand improvements are not deductible?  How do you differentiate?  

Example; Roof is shot and leaking so it will improve the value but also very necessary. 

Edit- as I continue reading roof would be cap ex so not deductible.