From the Desk of Juan Diaz

Every investor has a moment that changes their career. For me, one of my biggest real estate investing mistakes happened in Oakland back in 2007—yet it also became one of the most valuable lessons of my life.

I purchased a home built in 1902 on 82nd Street. The property looked promising, and like many new investors, I relied heavily on what appeared “fine” on the surface. I sent two guys from my team—Sam and Vincent—to inspect the property. They came back with the famous line that every buyer hears at least once:

“Looks like it’s remodeled.”

That one sentence became the beginning of one of my most expensive real estate investing mistakes.

Lesson 1: Never Assume—Inspect Everything

The facade of the house looked great—fresh paint, new lighting, and updated siding. But the moment I walked inside, the issues began:

  • Floors were uneven

  • The house felt like it was leaning

  • The roofline sagged

  • Odd smells came from the crawlspace

A deeper inspection revealed:

  • Rotten subfloor

  • Failing foundation

  • Water intrusion

  • Poor-quality past repairs

  • Hidden damage covered by cosmetic upgrades

This wasn’t a small fix. It was a complete rebuild of the bottom half of the home.

Lesson 2: Falling in Love With a Property Will Cost You

One of the most common real estate investing mistakes is emotional attachment.
Because the street was familiar to me and the outside looked great, I let my guard down.

Never fall in love with a deal.

A seasoned contractor later told me:

“If you don’t know construction, hire someone who does—or you will learn the hard way.”

Lesson 3: Your Circle Matters — Choose Wisely

Your network can either elevate you or blind you.

  • Some people will tell you what you want to hear

  • Others will save you thousands by telling you the truth

  • You need people around you who challenge you, not comfort you

Before buying ANY home—especially older California homes—verify:

  • Foundation replacement dates

  • Permit history

  • Roof life

  • Plumbing and electrical condition

  • Soil issues

  • Pest or dry rot damage

Due diligence is not optional. It’s survival.

Lesson 4: Budget for the Unknown

The repairs on this one Oakland home easily added six figures to the total investment.

As one mentor told me:

“You don’t need to know construction—but you must respect it.”

Always budget for hidden problems, especially when purchasing:

  • Homes older than 50 years

  • Fixers

  • Properties with previous renovations

  • Tenant-occupied homes

Surprises WILL come. Plan for them.

Lesson 5: Slow Down. Investigate More. Decide Wisely.

Before you buy:

✔ Double-check who inspected the property
✔ Ask for photos and videos of crawlspaces, attics, roof framing
✔ Evaluate the reliability of your team
✔ Make sure the numbers make sense even in a worst-case scenario

Real estate rewards the prepared—and punishes the careless.

Final Thoughts: Every Investor Pays for Their Education

Some pay through seminars.
Some through mentors.
Others—like me—pay through experience.

This Oakland deal became one of the most expensive but important lessons of my career. It taught me the true cost of skipping due diligence and the danger of trusting appearances.

If you want long-term success, learn from my real estate investing mistakes instead of repeating them.

And as my grandfather always said:

“You are who you hang out with—choose your people wisely.”