Like others have said, you cannot claim the tax losses until the funds are sold and "realized". 

Given the fact that if  there is a gain a future year the prior year loss can offset it, it seems that one would want to file the loss so they can offset that gain.

I can imagine this is a challenging decision to make.My thoughts:When hope is a key component of the plan of action, it is time to cut losses.

If you spend the entire $300k restoring the property, then here is the end result:- deductible casualty loss of $50k- no current tax- the restored property has $0 basis and cannot be depreciated- when it is later sold, the entire sale price is taxableMechanics and reporting are tricky, and I would not recommend to DIY it, especially since my scenario is over-simplified, and your real scenario is likely to involve more gotchas.Thanks so much. 

It's absolutely crucial investors know if they can or cannot use losses. 

But ultimately the responsibility lies in my hands.I jumped on a seesaw of risk hoping that the momentum would catapult my bank account into six figures only to find out the hard way that flipping houses isn’t as easy as I had predicted.This house was purchased for $64,000 with an expected rehab of $100k to $120k depending on how much work the dilapidated and neglected house needed.The midwest is lovely but the houses carry the weight of weather storms nearly a century old leading to more damage than a beginning investor could expect.The appraisal came in at $225k for my lender meaning our all-in cost would be around 85% of the sales price worst case.

Also what towns do you primarily rent in and how much of a loss do you take vs renting market rent?

First - Have a discussion if the rental loss will immediately help your tax situation. 

I'd recommend looking at costs. your build cost is going to be well over other homes because of the fixed costs like slab, Hvac, roof, etc. check the market drivers and weight the benefits of short term versus long term. long term is no furniture and help pays mortgage but at this size it doesn't really cover everything. we didn't find a lot of economies of scale in single family detached. can you build more than one unit?

Sure I have doubts now that I’m midway through renovations…but I feel the contacts I’ve gained in a new city (electricians, plumbers, etc) are worth their weight in gold.