There are partner/ownership concerns, liability issues, entity structures, is there a demand for the houses, zoning, surveys, appraisals, VOM, VOE, labor costs, infrastructure, county hearings, ROI, taxes, more taxes and yet more taxes, real estate agents and their fees, delays, Sub contractors, (who don't show) insurance, and on and on and did I say delays and more delays. 

I'm a retail net leased investment broker based in Los Angeles, and I specialize in single and multi-tenant retail properties leased to the national credit "daily needs" tenants ranging from the top grocers (The Albertsons Companies, The Kroger Company/Ralphs, Wal-Mart Neighborhood Center, Trader Joe's, Sprouts, Whole Foods), to the drug stores (Walgreens Boots Alliance/Rite Aid, CVS), to the discount retailers (Dollar Tree/Family Dollar and Dollar General).  

That's great Joe and wish you all the luck, i would definitely try and get it for a little less if you can, that's where you start to make money.  

@Del M. the price seems pretty high. sounds like you could be getting a bid from a GC or the company that provided you a quote uses Union Labor.

We will be using a combination of a refi (likely with a bit of cash out to bring us to 80% ltv) and/or second mortgage to fund the addition, but will be doing all the labor possible ourselves.

Thanks Joe and Iverem for the warm welcome!

Worst case you can at least offer to pay for the cost of the materials on a credit card which would leave you only having to pay cash for the labor.

Based on your thoughts @Russell Brazil @Stanley Parsley @Joe Delaney @David Dachtera @Joe Villeneuve, I started looking at less expensive houses in DC.

Originally posted by @Joe White:Your keywords - Chestnut Hill stands out as being different than the others.

Please see below for the breakdown: Current state appraisal value: $270,000Value after renovations: $330,000 (using a 2 mile radius)Mortgage debt: $78,110.34Credit line: $130,000Credit line fee: $100Interest rate on credit line: 3.5% (can freeze rate three times) Labor quoted by contractor: $50,000 (doesn’t include window replacements as not yet quoted)Materials: ???