I’d start by reaching out to local portfolio lenders (credit unions are great for this) or a broker (me) who does investor loans – they usually have products designed exactly for this situation and do a 2nd position that'll allow you to tap into the equity without touching your 1st. 

So, the foundation engineer designs the slab and on the annotations, he provides for the amount of concrete in Cubic Yards, including a schedule for the cables (we're doing post tension slabs) and the minimum PSI threshold for the quality of the concrete. 

Everything in there is designed to work against you.

Also, how much time do you spend on design?

You're right, ground-up construction is capital intensive and does alleviate some unknowns (but only when you have a strong design team). 

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The issue you have as you scale is that these are not designed for business use, and if they flag you as a business they will shut you down pretty quickly. 

Without significant apprection that could allow some extraction of value, the negative cash flow on some of these purchases at some point will go through most newbies reserves forcing a sale,   They are adults and made adult decisions and took adult risks.  

As mentioned above Im not sure which listing you want feedback on - but I did notice some typos and design flaws on your site, I recommend going through it with a fine tooth comb. 

Cheap materials, contemporary designs (again, cheap) that are not compatible with the area, horrendous locations.4.