As for repairs on the purchase of a home prior to auction there are some professionals utilized by the professionals for costs to repair the home in best and worst case scenarios.

I am purchasing STR insurance and have all licenses, but if something happened would HOA cover outside costs. 

What can I do to ensure there are no surprises after closing and avoid a costly eviction? 

Determine the most likely sales price of the build (factor in the cost of the land also) and include all selling costs to arrive at your net profit and ROI. 

This deal taught me the importance of overestimating rehab costs and always having a solid team of professionals on How did you find this deal and how did you negotiate it?

My condition was that they rent the house for 1% of the costs and sign a 3 year lease.

I wouldn't build the ADU just yet because like it was mentioned it cost more than you can really make a good return on.

Heating costs and interest rates dont help the numbers but demand is high and resale numbers have been impressive

It sounds like you might be doing a little eraser math (making a deal work from not estimating enough for costs) so beware of that.

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