Don't go talk to a buddy or a friend, you got to find somebody who can show you their performance.

Hello BP, brand new to real estate investing here and hoping to start somewhere.

If you've delivered a lease to the new tenant and they've signed and paid (there can be no legal contract without exchange of real and valuable goods and services), that person can sue you for performance and costs.

Make sure you let them know if you are performing any of the work, or if the repairs will ALL be made with contractors.

Verify income, credit score, and perform a background check.

As mentioned above you could just act as lender and record a mortgage/deed of trust with promissory note and personal guarantee from all parties in the deal would be the cleanest way to structure the deal.Another option which could potentially yield higher returns on your money is to become an equity partner in the deal, this could put your money in a riskier position and in the case of a default or failure to perform of other partners. 

My current builder has been not performing on a project I have and it is clear they are not doing anything to change their posture and improve or make up schedule.

I am brand new to this platform, and I may not be using it effectively?

Having a poor understanding of business, contracts, state and federal laws, negotiations, maintenance costs, etc. will continue to result in poor performance and finger pointing on both sides of the table. 

Carpet should last 7-10 years and I've seen some last for 20 and look like brand new.