Which area will you be building and what estimate cost per sqft ?

We are purchasing a SFH as a STR requiring work and need budget estimates and someone reliable to do the work as we are out of state investors. 

My initial thought is the best case scenario would be to cash out refinance my current home (i'm estimating $30,000 in equity) and buy another house to do a live in flip so I can rent my current house and use the cash to put towards another house.

So, a quick rough estimate of my expected usage: portland cement to water ratio is 2:1 with no aggregate added, foam to slurry ratio roughly 4:1.

I have an estimated $100k in equity that I could pull out with a cash out refi if I wanted to refinance again and increase my savings to around $150k. 

The quick and dirty formula for a BRRRR isPurchase price = 0.75 * ARV - Rehab CostsIn your case, you would need to acquire the property for ~$156.25k to make it a complete BRRRR deal.Side note, rehab costs are very hard to estimate so make sure you verify that estimate and/or allow for a significant margin of error in your calculations.

For example, if lite rehab is needed estimate X per square foot (i.e. maybe paint, carpet, small touch ups and improvements).  

If you are just starting out, then also know that your estimates are going to almost always come in too low.

Ask your mother and Father what they want done about the house--he has been living there free for a reason--maybe they will just deed it over to him.Maybe they like him more than you--or maybe he's the kind of person that needs more help than you (in your parents estimation).He has been living there free and clear for a long time.Here's an odd thought--maybe you were adopted and don't know it (seriously).Somehow he received a free house and you did not.Also you might want to look into living trusts (done by an attorney). 

I’m going to offer 90k using a conventional loan 20% down and cover the rehab myself(estimated 40k).