Note: This answers assumes this is your personal residence, not used as a rental or for business, and that you don't have insurance.
See publication 547.
https://www.irs.gov/forms-pubs/about-publication-547
In general, the amount of your loss is the loss in fair market value of the property. This generally requires an appraisal. Because the loss in FMV is sometimes difficult to determine, the IRS allows you to use the repair cost as an estimate in the loss of FMV, but only if the repair meets certain conditions. The IRS does not require you to use repair cost to determine loss in FMV, it is only one option, and it would not be appropriate in this case if, as you say, the repair did not restore the property to its previous condition.
Assuming you have a before and after appraisal documenting the loss in FMV of $100,000, you can declare a $100,000 casualty loss on form 4684. Because of the 10% deductible and the $500 per incident deductible, and because losses are an itemized deduction on schedule A, you will not get the full tax benefit of a $100,000 deduction. Your actual tax benefit will depend on your income and other tax situations. For example, if your AGI is $500,000, there is a $50,000 deductible on your loss, so your actual deduction would be $49,500.
Next, you have to reduce your home's cost basis by the amount of the loss deduction. In the example above where your net loss deduction was $49,500, you must reduce the home's cost basis by $49,500. This means you will have a larger capital gain and may pay more capital gains tax if and when you sell the home.
Next, you have the repair cost. Home improvements add back to the cost basis of the home (which reduce your future capital gains) but repairs do not. (You get no tax help for repairs.) An improvement is a betterment, it adds value, or extends the useful life of the home. Only you can determine if the "ugly fix" can count as an improvement, to increase the basis, or a repair, which does not. If you do include it in your basis, keep records of the work for as long as you own the home plus 3 years after you sell, in case of audit.
Finally, you can't claim any loss if it would have been covered by insurance, even if you chose not to make a claim. Suppose your insurance would have covered $50,000 of the damage. You can only claim a loss of $50,000. Then, the 10% deductible and $500 deductible will further reduce the amount you can deduct on your taxes.
The fact that your $10,000 "ugly fix" raised the value of your home by $70,000 is peculiar, and I wonder about the competence of your appraiser, but it doesn't change the tax position. You had a $100,000 loss, and then you made either a $10,000 improvement, or a $10,000 repair. It's similar to if you had invested $10,000 to remodel the kitchen, but It made the home so much more desirable that it raised the value by $70,000. You only get a cost basis adjustment equal to what you actually spent, not how the market values that spending. And as noted above, the $10,000 might not even be an improvement.
