It has taken me time and I am ok with building long term wealth vs spendable dollars today.

This does not align with buying most buildings in cash.Once you progress in your investing efforts you may come across more UHNW individuals, family offices and institutions who would take the lower return for limiting risk (all cash deal).

Instead of platforms like Angi, try building relationships directly with contractors, architects, and developers.

IF it is a real problem, then yes, fix it.I would build a fir-in wall out of 2x2s and insulate it heavily (Rockwool comes to mind https://www.rockwool.com/north-america/) There is also drywall that is made for this.

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.

HighLevel - plenty of build outs for LOs or brokers.

Then, start building your connection with local agents, contractors and property managers.2. 

I've seen estimates of $200 to $400 per square foot for SoCal with $700 sq ft for something higher end and building up a hill and but possibly higher for San Francisco Bay Area (lhigher labor costs, etc.).  

I began shopping for a large construction loan to build a new car wash on the land. 

My goal is to build a successful flipping business while keeping family time a top priority.