Instead I have decided to add some extra electrical outlets and put in lights and rent it as a workshop.

I haven't seen anything under 200-250k all in cost  Part of it is detached garage and using existing structure + existing electrical.

It will be dependent on how much cutting they have to do and coordination with other MEP systems such as electrical and HVAC.

They said the building would need to be updated for plumbing and electrical as it was 65 years old. 

When it comes to anything major like electrical, plumbing, or structural...I think you need a permit.

Electric baseboard heat is a cheap way to replace an old furnace that feeds several units which you pay for.8.

If any of the "Big Five" systems (HVAC, plumbing, roof, electrical, water heater) haven't been updated recently, they still should be budgeted, even if you expense them later.Also, if you're primarily buying for cash flow, then this seems like a whole lot of work for just 7.75% CoCR!

Here's what the quote covers:- Conversion of 2 bedroom, 1 bath main house to 3 bedroom, 2 bath (~1040 sf footprint)- Demolition of existing walls (existing dining room wall, wall between kitchen and living, bathroom closet)- Finished Shell (Reframing opening to living room and kitchen, shifting openings for bathroom/bedroom, new walls at bathroom and dining, level - Replace all aluminum windows with fiberglass windows and screens- Upsizing plumbing, and relocating fixture locations as necessary- Upgrading electrical panels- Assume heat pump and ductless mini-split for heating and cooling- An allowance for kitchen appliances including combination range, hood, dishwasher, microwave, refrigerator, and washer/dryer- An allowance for mid-grade plumbing and lighting fixtures (Delta, Kohler, or equivalent)- Mid-grade plumbing and lighting fixtures (Delta, Kohler, or equivalent)- Ikea cabinets or equivalent with solid surface countertops, includes island- Assume solar system to be installed on the house including battery storageFor the garage ADU, the garage would need to be demoed and rebuilt, but we would benefit from building within the setback since the garage is on the property lines.

By the time it reaches the tax sale, the property has often been vacant for many years, with all the electrical, plumbing, and HVAC components having been stolen. 

Turns out the the electrical company was repairing a down line and once it was restored it sent a huge surge to the electrical panel.