The HELOC has doubled this past year or so, due to variable rate, but fortunately the rent still covers costs at the moment.  

Construction cost a fortune in the Bay Area, not to mention design/engineering fee and permit process.

I hear a lot of talk about how wonderful and how easy the SW belt is at making big fortunes with huge cash flows and multiplying profits, but never hear about the realities of investing here and what the market is actually doing "today", which is a far cry from what I'm reading about.

I've fortunately not had this specific scenario yet, but my two options I've given myself are 1) if it is totally unusable I'll offer to rebate the number of days for the tenant at a prorated rent on next month's rent they can choose to spend their savings on a hotel or they can stay with someone else it's 100% their choice (I don't want to pay for a hotel since then we have to agree on what standard of hotel is acceptable) 2) If it is partially useable and they are willing to be accommodating like Nathan said I'd provide a gift card or two for dinner etc. 

We were fortunate to buy when the market was at its low; currently it’s at an all time high.   

Home to The Ohio State University with nearly 60,000 students, 5 fortune 500 companies, over +25% population change since 2000, 2016 smart city challenge award winner gaining 50 million dollars in funding from the government (https://www.columbus.gov/smartcity/), Intel is spending 20 Billion dollars to build two semiconductor plants, and many many more great things presently and coming in the future.

I've heard great things about all and fortunately, they aren't all identical.  

Fortunately, prices have gone up recently so I should be able to make a profit and put this all behind me.

Fortunately, California provides this if a CA-licensed broker is used, who follows the rules for originating fractionalized loans.

Fortunately we have been in the same area for 12 military years, but hoping to rent to the more temporary military members in our area.