In my market, which is a fairly economical place to build, I am friends with full time builders that are in their properties about $150k/door for construction level finishes.  

A reserve is unnecessary, but I still keep around $15,000 - $20,000 in my account.The point is, that you should sit down and assess your finances to determine what the worst-case scenario may look like, how much you would need to cover it without impacting your life, and whether you will need to build a reserve.

Chris answer is spot on.I'll add "quick closing".You won't find investors easily, you have to go to a lot of meetups to build them.

The options are, demo the lot, split the lot and then sell 2 lots to the builder or build myself.

It is very messed up and I am trying to remove it from the building to avoid and further mess.So she started arguing and I gave her one week to remove her stuff.

Personally, If I could pull out a HELOC, I would use it to fix and flip which will typically make sense as you shouldnt be keeping the money out for that long and you can recycle it or pay it back and build off the capital that you got from. the flip.

Is this a new build?  

If it could even break even, I'd be fine not cash flowing as long as I was building equity.

Other most common factor: Family Size increases due to marriage or having a child. 

I have seen people buy non-existant properties, bottom of lake (literally underwater), slivers of land too narrow or small to do anything, Army bombing range, expired leases, cell tower now removed, property with 30 year lease and prepaid rent for 30 years, condemned buildings, toxic waste sites, land under railroad tracks, cliffs, landlocked property, wetlands, flood zone, unbuildable property, endangered species habitat, ....I have three rules for buying at Tax Sale:1.