Does anyone have experience with an 80/10/10 "piggyback" loan (in the context of a house hack is even better)? I just heard about this financing option from a real estate agent and would be interested in hearing about your experiences! 

The reason buyers use the 80/10/10 loan is to avoid mortgage insurance. If you have 10% down, then the 1st mortgage is a conventional (Fannie or Freddie loan) at 80%, followed buy a simultaneous HELOC up to 90%. With that set up, you avoid mortgage insurance because the 1st is no more than 80%. This generally results in a lower monthly payment versus a 90% first mortgage with MI.

These types of mortgages are common place, and a good tool to look at when buying a home. 

HELOC I thought the other ten percent came from a secondary LOAN

@Dwayne Bartoin Oops, I wasn't keeping tabs on this thread. Sorry it took me so long to respond. A HELOC is a 2nd mortgage lien. You can also use a closed end 2nd mortgage as well, but most borrowers want the advantage of having a line of credit as the 2nd.

So again, here is the structure:

1st Mortgage for 80% with no MI

2nd Mortgage or Heloc up to 90%

Your 10% down payment to make 100%

This structure, allows you to avoid MI, get the best rates and have a line of credit that can be used in the future to draw on if and when needed. 

I hope this helps?

One of the "10s" can also come from the Seller, if they're willing to carry back.  Some will for a short period.  Check if that affects the underwriter's ability to make it work though.  Some demand you have 10% "skin in the game".

@Erik W. when you say, "carry back," do you mean seller financing?

@Jacob Seim , correct.